Determination of the δ(

34S/32S) of 

Low-Concentration Sulfate in 

Water: RSIL Lab Code 1949

Chapter 8 of 

Book 10, Methods of the Reston Stable Isotope 

Laboratory 

Section C, Stable Isotope-Ratio Methods 

Techniques and Methods 10-C8 

U.S. Department of the Interior 

U.S. Geological Survey

Determination of the δ(

34S/32S) of 

Low-Concentration Sulfate in 

Water: RSIL Lab Code 1949 

By Kinga Révész and Haiping Qi 

Chapter 8 of 

Book 10, Methods of the Reston Stable Isotope 

Laboratory 

Section C, Stable Isotope-Ratio Methods 

Edited by Kinga Révész and Tyler B. Coplen

Techniques and Methods 10-C8 

U.S. Department of the Interior 

U.S. Geological Survey 
U.S. Department of the Interior 

GALE A. NORTON, Secretary 

U.S. Geological Survey 

Mark D. Myers, Director 

U.S. Geological Survey, Reston, Virginia 2006 

Revised July 2007

For sale by U.S. Geological Survey, Information Services 

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products: 

Telephone: 1-888-ASK-USGS

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Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Although this report is in the public domain, permission must be secured from the individual copyright owners to

reproduce any copyrighted material contained within this report. 

Suggested citation: 

Révész, Kinga, and Qi, Haiping, 2006, Determination of the δ(

34S/32S) of Low-Concentration Sulfate in Water: RSIL Lab 

Code 1949, chap. C8 of Révész, Kinga, and Coplen, Tyler B., eds., Methods of the Reston Stable Isotope Laboratory: 

Reston, Virginia, U.S. Geological Survey, Techniques and Methods, book 10, sec. C, chap. 8, 35 p. 
Foreword 

The Reston Stable Isotope Laboratory (RSIL) provides stable isotope analyses on a routine basis 

for a large user community within the U.S. Geological Survey (USGS) and elsewhere. The RSIL 

also serves the USGS National Research Program (NRP) through its project on Stable Isotope 

Fractionation in Hydrologic Processes. The NRP conducts basic and problem-oriented hydrologic 

research in support of the mission of the USGS. The stable isotope project conducts research on

the use of isotope-ratio measurements in studies of water resources and environmental quality. 

One objective of this project is to develop new techniques for isotopic analysis of H, N, O, C, and 

S in environmental samples. New analytical techniques expand the range of tools available for 

studying the movement of those elements in hydrologic and biogeochemical systems. Another 

objective of the project is to test new applications of isotope measurements in specific field 

settings. Field studies of isotope behavior have contributed to understanding of water-supply 

sustainability, ground-water/surface-water interactions, paleoclimate history, biologic cycling of 

nutrients, ground-water contamination, and natural remediation. This project also contributes to 

the improvement of measurement science and the development of isotope databases. 

Book 10 of the Techniques and Methods Series of the USGS contains detailed descriptions of 

methods of the RSIL, including routine analytical methods called standard operating procedures 

(SOPs), along with safety guidelines, maintenance procedures, and other information about the 

operation of the RSIL. Section C of Book 10 contains the SOPs for a variety of methods to 

measure stable isotope ratios, each of which constitutes a chapter. Each chapter is limited to a 

narrow field of subject matter to permit flexibility in revision as the need arises. 

Pierre Glynn 

Chief, Branch of Regional Research, Eastern Region

 iii

Contents 

Foreword........................................................................................................................................................iii

Conversion Factors, Acronyms, and Abbreviations ..............................................................................vii

Summary of Procedure.................................................................................................................................1

Reporting Units and Operational Range ....................................................................................................1

Reference Materials and Documentation.................................................................................................2

Reference Materials Used, Storage Requirements, and Shelf Life......................................2

Documentation ..............................................................................................................................2

Labware, Instrumentation, and Reagents .................................................................................................2

Sample Collection, Preparation, Analysis, Retention Times, and Disposal.........................................4

Sample Containers, Preservation, and Handling Requirements ...........................................4

Sample Preparation and Time Requirements...........................................................................6

Performing the Analysis and Time Requirements ...................................................................6

Problematic Samples....................................................................................................................7

Interferences .................................................................................................................................7

Troubleshooting and Bench Notes ............................................................................................8

Maintenance and Maintenance Records .................................................................................8

Sample Retention Time and Disposal ........................................................................................9

Data Acquisition, Processing, Evaluation, Quality Control, and Quality Assurance ..........................9

Laboratory Information Management System for Light Stable Isotopes (LIMS-LSI) ........9

Quality-Control (QC) Samples......................................................................................................9

Acceptance Criteria for All QC Samples .................................................................................10

Corrective Action Requirements ..............................................................................................10

Responsible Parties for All QA/QC Functions for Procedures Covered in RSIL SOPs.....10

Data Management and Records...............................................................................................10

Health, Safety, and Waste-Disposal Information...................................................................................10

Applicable Health and Safety Issues.......................................................................................10

Personal Protection....................................................................................................10

Electrical Hazards.......................................................................................................11

Chemical Hazards .......................................................................................................11

Gas Cylinder Handling................................................................................................11

Specific Waste-Disposal Requirements .................................................................................11

Revision History ...........................................................................................................................................12

References Cited .........................................................................................................................................13

Appendixes...................................................................................................................................................14

A. Step-by-Step Procedure to Log-in Samples to LIMS-LSI ..............................................14

B. Step-by-Step Procedure to Prepare Resin for Field Collection and Elute 

Sulfate from Resin after Field Collection ..........................................................................16

C. Step-by-Step Procedure to Precipitate BaSO4 ................................................................17

D. Step-by-Step Procedure to Generate an Excel Sample Workbook or to Print a 

Template and a Samples-to-Be-Analyzed List ................................................................19

E. Step-by-Step Procedure for Weighing and Storing Samples .......................................23

F. Step-by-Step Procedure for Zero Blank Auto Sampler Operation...............................24

G. Step-by-Step Procedure to Add Sample Information to Sequence Table..................25

H. Step-by-Step Procedure to Retrieve Data from ISODAT 2.0 for LIMS-LSI and for 

Data Back-Up ........................................................................................................................26

I. Step-by-Step Procedure to Transfer Data to LIMS-LSI, to Transfer Data to

Back-Up Computer, and to Reevaluate Old Data ............................................................27

J. Step-by-Step Procedure to Determine and Apply Correction Factors and 

Evaluate Data ........................................................................................................................28

K. Step-by-Step Procedure to Check Elemental Analyzer for Leaks................................29

 v 
L. Daily Checklist.......................................................................................................................30

M. Changing the Insertion Tube...............................................................................................31

N. Changing the Water-Trap....................................................................................................32

O. Changing the Reaction Tube...............................................................................................33

P. Step-by-Step Procedure to Report Data...........................................................................34

Figures 

 1. Diagram of the Carlo Erba Instruments NC 2500 E (CE NC 2500) Elemental Analyzer. ..................3

 2. Diagram of a Finnigan ConFlo II Open Split...........................................................................................4

 3. Schematic of a continuous flow isotope-ratio mass spectrometer (CF-IRMS)..............................5

 vi 
Conversion Factors 

Multiply By To Obtain 

Length 

millimeter (mm) 0.03937 inch 

centimeter (cm) 0.3937 inch 

meter (m) 3.281 foot 

Volume

micro liter (μL) 0.0610210

–3 cubic inch 

milliliter (mL) 0.06102 cubic inch 

cubic centimeter (cm3

) 0.06102 cubic inch

Mass 

nanogram (ng) = 10–3μg 3.527 × 10–11 ounce 

microgram (μg) = 10–3 mg 3.527 × 10–8 ounce 

milligram (mg) = 10–3 g 3.527 × 10–5 ounce 

gram (g) = 10–3 (kg) 3.527 × 10–2 ounce 

kilogram = 103

 g; 106 mg; 109μg; 1012 ng 2.205 pound 

Density 

gram per cubic centimeter (g/cm3) 0.5780 ounce per cubic inch 

Temperature 

Celsius (°C) °F = 9/5 (°C) + 32 Fahrenheit (°F) 

Pressure (force/area) 

kilopascal (kPa) 9.869 × 10–3 atmosphere, standard (atm) 

kilopascal (kPa) 1.450 × 10–1 pound-force/square inch (psi) 

kilopascal (kPa) 1.000 × 10–2 bar 

kilopascal (kPa) 2.961 × 10–1 inches of mercury at 60°F 

Acronyms and Abbreviations 

ANSI American National Safety Institute 

ASR analytical services request

CF-IRMS continuous flow isotope-ratio mass spectrometer 

DIW deionized water 

EA elemental analyzer 

GC gas chromatograph 

IAEA International Atomic Energy Agency

 vii 
IRMS isotope-ratio mass spectrometer 

LIMS-LSI Laboratory Information Management System for Light Stable Isotopes 

mg/L milligram per liter 

MSDS Material Safety Data Sheets 

NBS National Bureau of Standards 

NFPA National Fire Protection Association 

NWQL National Water-Quality Laboratory (USGS) 

PCM polycarbonate membrane 

per mill, ‰ 1/1000 

pF picofarad 

QA quality assurance 

QC quality control 

QC/QA quality control/quality assurance 

RSIL Reston Stable Isotope Laboratory

SOP standard operating procedure 

USGS U.S. Geological Survey

VCDT Vienna Cañon Diablo Troilite 

Symbols 

Ω ohm

< less than 

> greater than 

≥ greater than or equal 

≤ less than or equal 

 viii 
Determination of the δ(

34S/32S) of Low-Concentration 

Sulfate in Water: RSIL Lab Code 1949 

By Kinga Révész and Haiping Qi 

Summary of Procedure 

The purpose of Reston Stable Isotope Laboratory (RSIL) lab code 1949 is to determine the δ(

34S/32S), 

abbreviated as δ34S, of dissolved sulfate having a concentration less than 20 mg/L. Dissolved sulfate is 

collected on an anion-exchange resin in the field, eluted in the laboratory with 3 M KCl, and precipitated 

with BaCl2 at pH 3 to 4 as BaSO4. The precipitated BaSO4 is filtered and dried before introduction into an 

elemental analyzer (EA) Carlo Erba NC 2500. The EA is used to convert S in a BaSO4 solid sample into 

SO2 gas, and the EA is connected to a continuous flow isotope-ratio mass spectrometer (CF-IRMS), 

which determines differences in the isotope-amount ratios of stable sulfur isotopes (34S/32S) of the product 

SO2 gas. The combustion is quantitative; no isotopic fractionation is involved. Samples are placed in a tin 

capsule and loaded into the Costech Zero-Blank Autosampler of the EA. Under computer control, 

samples are dropped into a heated tube reaction tube that combines the oxidation and reduction reactions. 

The combustion takes place in a He atmosphere containing an excess of oxygen gas at the oxidation zone 

at the top of the reaction tube. Combustion products are transported by a He carrier through the reduction 

zone at the bottom of the reaction tube to remove excess oxygen and through a separate drying tube to

remove any water. The gas-phase products, mainly CO2, N2, and SO2, are separated by a gas 

chromatograph (GC). The gas is then introduced into the isotope-ratio mass spectrometer (IRMS) through 

a Finnigan ConFlo II interface, which is also used to inject SO2 reference gas and He for sample dilution. 

The IRMS is a Finnigan DeltaPlus CF-IRMS. It has a universal triple collector with two wide cups and a 

narrow cup in the middle. It is capable of measuring mass/charge (m/z) 64 and 66 simultaneously. The ion

beams from SO2 are as follows: m/z 64 = SO2 = 

32S16O16O; m/z 66 = SO2 = 34S16O16O primarily. 

Reporting Units and Operational Range 

Variations in isotope-amount ratios typically are small. Stable isotope–amount ratios commonly are 

measured and expressed as the relative difference in the ratio of the amount of the less abundant isotope 

(usually the heavy isotope) to the amount of the more abundant isotope (usually the light isotope) of a 

sample with respect to a reference. This relative difference is designated δi

E, which is a shortened form of 

δ(

i

E/jE) or δ(

i

E) and is defined according to equation 1: 

 

( ) ( ) ( ) ( ) ( ) ( )

n ( ) n ( )

n n n n δ = δ = δ = i j

i j i j

i i i j

E E

E E E E

E E E E

ref ref

X X − ref ref (1) 

where i and j are isotopes of element E, and n ( E)/n ( E) and n ( E)/n ( E) are the ratios of the isotope 

amounts in the unknown X and a reference ref

X

i

X

j

ref

i

ref

j

. A positive δiE value indicates that the unknown is more 

enriched in the amount of the heavy isotope ( E) i than is the reference. A negative δi

E value indicates that 

the unknown is depleted in the amount of the heavy isotope relative to that of the reference. Values of δ iE 

have been reported in parts per hundred (% or percent), parts per thousand (‰ or per mill), and parts per 

ten thousand. For stable sulfur isotope–amount ratios, δ S34 is defined as follows: 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 1 Effective: March 3, 2004
( ) ( ) ( ) ( ) ( ) ( ) ( ) S ( S)

S S S S S S S S 32

ref

34

ref

32

ref

34

ref

32

X

34

34 34 34 32 X

n n

n n n n δ δ = δ − = = (2)

The primary reference material for relative sulfur isotope-ratio measurements (δ34S) is IAEA-S-1, 

which has a consensus δ34S value of –0.3 ‰ relative to Vienna Cañon Diablo Troilite (VCDT)(Robinson, 

1995; Krouse and Coplen, 1997; Coplen and Krouse, 1998). By interspersing isotopic reference materials 

with accepted isotopic compositions among unknown samples, δ34S values can be determined. These δ34S 

measurements are made with a CF-IRMS, which measures the isotope-amount ratios of the sample SO2

gas and one or more injections of the “working reference” SO2 gas. Values of δ S typically are reported 

in parts per thousand (‰).

34

 

The system was tested by analyzing BaSO4 samples with known δ34S values. The routine analysis 

requires a minimum of 40 μg of sample as sulfur; however, the system is capable of analyzing samples as

small as 19 μg of S in one sample aliquot with reduced analytical precision. The δ34S values of test 

samples ranged from approximately –34 to +21 ‰, which covers the range of δ34S of most sulfate in 

natural water. The precision and accuracy of the results were acceptable (± 0.2 ‰), and no memory

effects were observed. 

Reference Materials and Documentation 

Reference Materials Used, Storage Requirements, and Shelf Life 

The primary reference material for δ34S measurements is IAEA-S-1, which has a consensus δ34S 

value of –0.3 ‰ relative to VCDT (Robinson, 1995; Krouse and Coplen, 1997; Coplen and Krouse, 

1998). Other internationally distributed reference materials that are used have a wide range of δ34S values. 

In the procedure reported herein, barium sulfates (BaSO4) that are used for isotopic analysis of inorganic 

samples include NBS127 with a δ34S of +21.1 ‰, IAEA-SO-5 with δ34S of +0.5 ‰, and IAEA-SO-6 with 

δ34S of –34.05 ‰. No locally prepared isotopic reference materials are used in this method. 

All of these reference materials are stored in the RSIL at room temperature in glass bottles capped 

with Teflon-coated or cone-shaped caps to keep moisture out. Their shelf life is indefinite. 

Documentation 

All calibration results are stored in the Laboratory Information Management System for Light Stable 

Isotopes (LIMS-LSI) (Coplen, 2000) under the following sample identifiers: S-1301 (IAEA-SO-5); S-97 

(NBS127); and S-1302 (IAEA-SO-6). 

Labware, Instrumentation, and Reagents 

Preparatory labware, instrumentation, and reagents, include (Amberlite IRA-400 (RN(CH3)3 + 

Cl–

) anion-exchange resin, 3 M KCl solution, 1 M HCl, 20 weight % BaCl2 solutions, beakers, a stirring 

hot plate with stir bar, a watch glass, a thermometer, a filtering apparatus with 0.2-μm Millipore GTTP 

polycarbonate membrane (PCM) filter, tin capsules, and a microbalance capable of measuring samples 

with 0.0001-mg precision. The analytical apparatus consists of four different segments: (1) EA, 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 2 Effective: March 3, 2004
(2) ConFlo interface, (3) IRMS, and (4) computer software. 

The EA is a Carlo Erba Instruments NC 2500 (CE NC 2500) system, and it has a Costech “Zero 

Blank” Autosampler that holds 49 samples enclosed in tin capsules (fig. 1). Each tin capsule falls into the 

reaction tube, which is kept at 1020°C and is under constant He flow (90 mL/min). The sample 

immediately reacts with a measured amount of oxygen from a 5-mL loop purged at 35 mL/min. The 

reaction of oxygen with the tin capsule is exothermic, resulting in localized temperatures of up to 1800°C, 

thus ensuring complete and instantaneous sample combustion. This is called “dynamic flash combustion.” 

Because the BaSO4 has a decomposition temperature of 1580°C, it is critical to synchronize the He flow, 

the oxygen flow, and the timing of the sample drop to achieve quantitative combustion (Révész, 1998; 

also see in the present report the section titled “Troubleshooting and Bench Notes”). To boost the 

combustion, 0.8 ± 0.3 mg V2O5 is added to each sample (Yanagisawa and Sakai, 1983). The combustion 

gases are first carried by He through an oxidative catalyst layer (tungsten oxide, WO3, on alumina) in the 

Figure 1. Diagram of the Carlo Erba Instruments NC 2500 E (CE NC 2500) Elemental Analyzer (used with permission from

Thermo Electron Co.). 

top of the reaction tube, where oxidation is completed, and then through a reduction agent (Cu) packed on 

the bottom of the reaction tube where any excess oxygen gas is consumed. At the outlet of the reaction 

tube, the gas mixture (N2, CO2, SO2, and H2O) enters a trap containing Anhydrone, which absorbs water. 

The gas mixture, now N2, CO2, and SO2, flows through a Teflon tubing gas chromatograph column

(0.8-m Poraplot W kept at 90°C), which separates the gases and ensures that pure sulfur dioxide gas 

passes separately through the thermal conductivity detector, through the ConFlo II open split, and into the 

IRMS. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 3 Effective: March 3, 2004
The Finnigan ConFlo II provides the means for coupling the EA to the CF-IRMS with an open-split 

arrangement (fig. 2). The principle of an open split is that it reduces the 90 mL/min He flow needed to 

operate the EA to a 0.3 mL/min He flow needed to operate the IRMS. This is achieved by placing the end 

of the capillary that leads to the IRMS directly in the flow of He coming from the EA. The narrow 

diameter and length of this capillary limit the flow of gas into the IRMS. Furthermore, extra capillaries 

carrying reference gas or He gas can be added to the open split, thereby making it possible to inject 

reference gas into the IRMS or to dilute the sample with extra He if the sample is too large (or to direct 

gases away by dilution if they are too large to ensure total separation).

Figure 2. Diagram of a Finnigan ConFlo II Open Split (used with permission from Thermo Electron Co.).

The IRMS is a Finnigan DeltaPlus CF-IRMS (fig. 3). The fundamental principle of the CF-IRMS 

technique is that a carrier gas transports the analyte through an initial stage of online chemistry for 

conversion to a form acceptable by the IRMS (Brenna and others, 1997). This is an automated system

generating online, high-precision, δ values of bulk solid and nonvolatile liquid samples. In the IRMS, gas 

molecules are ionized in a source by electrons emitted from a hot filament. The ions are accelerated into 

an analyzer, separated in a magnetic field, and collected in Faraday cup collectors. The ion beam

intensities are measured with electrometers. This IRMS has a universal triple collector with two wide 

cups and a narrow cup in the middle. The resistor–capacitor combination on the electrometer of the lowmass cup is 3 × 108 Ω and 680 pF. At the high-mass cup, it is 3 × 1010 Ω and 5 pF. The instrument is 

capable of measuring m/z 64 and 66 simultaneously. 

The Finnigan ISODAT 2.0 software is designed (1) to advance the autosampler carousel, (2) to 

control the ConFlo II interface to inject reference gases at the desired time and dilute the sample if 

desired, (3) to operate the IRMS, (4) to acquire data from the IRMS, and (5) to calculate delta values. 

Sample Collection, Preparation, Analysis, Retention Times, and 

Disposal 

Sample Containers, Preservation, and Handling Requirements 

Carmody and others (1998) discuss in detail sample collection of dissolved sulfate samples for 

determination of δ34S values. Sulfate and sulfide concentration should be determined in the field by ion 

chromatograph or spectrophotometer. Each sample that contains less than 20 mg/L of sulfate is collected 

on a column containing approximately 20 mL anion-exchange resin (Amberlite IRA-400 (RN(CH3)3 + 

Cl–

), which is provided by RSIL (see http://isotopes.usgs.gov/). The RSIL is responsible for removing any

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 4 Effective: March 3, 2004
Figure 3. Schematic of a continuous flow isotope-ratio mass spectrometer (CF-IRMS) (modified from Clark and Fritz, 1997). 

trace SO4

2– from the resin by rinsing 500 g resin with 2 L of 3 M KCl and rinsing it with 3 L of deionized 

water (DIW). The sample is collected in the field in a large 10-L bucket and acidified with 1 M HCl to pH 

3 to 4. The sample is then pumped by a peristaltic pump through the ion-exchange column at a speed of 

0.4 L/min. It is critical not to exceed the capacity of the resin. The resin column provided by the RSIL has 

the capacity of holding 2.3 g sulfate, which is substantially greater than the capacity needed. Thus, it can 

collect sulfate safely from 2 L of water with a sulfate concentration of 10 mg/L, 4 L of water with a 

sulfate concentration of 5 mg/L, and 20 L of water with a sulfate concentration of 1 mg/L. Resin columns 

must be labeled in the field with isotopes whose delta values are to be determined and with the respective 

laboratory code or schedule number. 

If a water sample contains dissolved sulfide, care should be taken during collection not to expose the 

sample to air to minimize oxidation of sulfide to sulfate. Alternatively, each sample that contains more

than 0.01 mg/L sulfide or has a sulfate/sulfide ratio less than 40 must be bubbled with N2 gas to strip 

sulfide from it prior to collection of sulfate. Trace oxidized sulfide could seriously alter the δ34S of 

sulfate. Sulfide is stripped by filling a 10-L bucket with the water sample, acidifying it to pH 3 to 4 with 

1 M HCl, immersing the outlet of the N2 flow into the bottom, covering the system loosely with plastic 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 5 Effective: March 3, 2004
wrap, and purging for 10 to 20 min with an N2 flow rate of 8 L/min until the sulfide concentration is less 

than 0.01 mg/L. 

No treatment, preservation, or special shipping is required. 

Sample Preparation and Time Requirements 

Sample preparation involves logging in samples to the LIMS-LSI, processing samples to precipitate 

BaSO4, creating a sample work-order sheet, and weighing samples into capsules. 

The logging-in procedure involves logging samples in batches to LIMS-LSI that could contain from 1 

to 100 samples per batch (also called a project), printing labels for each sample, and printing a summary

project report. Each sample label contains the Field ID (the identifier by which the sample submitter 

knows each sample) and the unique RSIL Lab ID assigned by the LIMS-LSI. The summary project report 

is inserted into a three-ring binder titled “Samples in Progress.” 

If samples are submitted through the USGS National Water Quality Laboratory (NWQL), the Field 

ID is a unique number for each sample assigned according to NWQL guidelines; this unique number is 

written on the analytical services request (ASR) form accompanying a sample, and the ASR information 

is entered into the LIMS-LSI system. This information is e-mailed to the submitter of the samples for 

identification of any errors and subsequently e-mailed to NWQL. Copies of the ASR forms are mailed to 

NWQL. Step-by-step procedures are given in Appendix A. 

The processing of samples involves (1) the elution of sulfate from resin, and (2) the precipitation of 

pure BaSO4 from the eluant (modified from Carmody and others, 1998). The resin is eluted with 150 mL

of 3 M KCl at a flow rate of 3 mL/min. Step-by-step procedures are given in Appendix B. The BaSO4 is 

precipitated by acidifying the eluant to pH 3 to 4 by addition of approximately four drops of 1 M HCl, 

heating it at 90°C, and stirring continuously for 45 min. This process removes all the carbonate as CO2

gas from the sample. If the samples contain organic material, 6 mL of 6 % H2O2 are added along with the 

acid to oxidize the dissolved organic sulfur to SO2 and oxidize any dissolved organic carbon to CO2, 

which are then degassed from the samples. At the last minute, 5 mL of 20 % BaCl2 solution is added to 

the sample to precipitate the BaSO4. The solution is cooled slowly to 50°C or lower and usually allowed 

to settle overnight. The liquid containing the BaSO4 precipitate is filtered through a preweighed 0.2-μm

GTTP PCM filter, rinsed with DIW, and dried in a sulfate-free oven at 90°C. After weighing the dried 

precipitate and the filter, the yield is determined for reassurance of quantitative precipitation of sulfate. 

The BaSO4 precipitate is scraped off the filter into a vial, homogenized with a spatula, and stored for 

analysis. It is recommended that samples be dried overnight at 90°C and be put into sealed vials as soon 

as they are removed from the oven. Before weighing, a sample in a vial must be homogenized with a 

spatula or with an agate mortar and pestle. If more than a single filter paper is used for the same sample, 

the precipitates must be combined and homogenized. The detailed procedure can be found in Appendix C. 

An Excel sample workbook is generated. The step-by-step procedures are shown in Appendix D. 

Sample weighing includes balance conditioning, weighing an appropriate amount of a sample into a 

capsule, recording the weight on the template, adding approximately 600 μg of V2O5 to the capsule, and 

closing the capsule by folding it. Step-by-step procedures are given in Appendix E. The time required for 

sample preparation is approximately 5 to 8 days. 

Performing the Analysis and Time Requirements 

All BaSO4 samples precipitated from water samples are prepared and analyzed in batches of a 

maximum of 80 per day, and all samples are analyzed in duplicate. Six aliquots of three internationally

distributed isotopic reference materials with different δ34S values are analyzed at the beginning of a batch. 

Four of them are depleted in 34S, one is enriched in 34S, and one has an intermediate value. A set of these 

three reference materials also is interspersed among the samples. At least one reference material set is 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 6 Effective: March 3, 2004
analyzed for every 10 unknowns. The amount of sulfur in the reference materials must be in the same

range as that of the samples. 

The procedure involves loading the autosampler carousel with capsules containing an appropriate 

amount of sample in sequence according to the “Template” (Appendix F), loading a new sample heading 

(including sample weights) into the “Sequence Table” in ISODAT 2.0 of the IRMS software, choosing 

the appropriate “Method,” and starting sequence acquisition (Appendix G). After the analyses are 

completed, data are exported (Appendix H) to a Zip disk or “memory stick” from the ISODAT 2.0 

database and transferred (Appendix I) to the LIMS-LSI system and Data Back-Up computer. Final daily

correction factors are determined by LIMS-LSI (Appendix J), based on the daily analyses of reference 

materials using equations 3, 4, and 5, below, which are presented with example numerical values: 

–34.05 ‰ = m × δ34S IAEA-SO-6 - workingref.gas + b (3) 

+0.50 ‰ = m × δ34S IAEA-SO-5 - workingref.gas + b (4) 

+21.10 ‰ = m × δ34S NBS127 - workingref.gas + b (5) 

The values –34.05 ‰, +0.50 ‰, and +21.10 ‰ are the assigned values of the international reference 

materials IAEA-SO-6, IAEA-SO-5, and NBS 127, respectively. The δ34Sref - workingrefgas values in equations 

3–5 are the daily mean delta values of the respective international reference materials relative to the 

working reference gas; b is the additive correction factor, and m is the expansion-coefficient correction 

factor. When two or more reference materials with different δ34S values are analyzed, the correction for 

sample blank does not need to be applied if the magnitude of the blank in the samples and reference 

materials is identical. However, if a single reference material is analyzed, only one-point calibration is 

possible; therefore, a blank correction must be applied. 

If replicates do not agree within acceptable tolerances, they are analyzed until acceptable statistics are 

achieved. The computerized LIMS-LSI will not release data until the statistics are acceptable. The time 

required for performing the analyses is a minimum of 2 days. 

No correction is made for the effect of sulfate δ18O value on the δ34S determination; V2O5 is added to 

each sample to buffer the δ18O of SO2 gas (Yanagisawa and Sakai, 1983). 

The systematic procedure is listed in the “Lab Procedures” binder at RSIL. The supervisor reviews 

suggested changes before they are adopted. 

Problematic Samples 

Problematic samples include those in which the sulfate concentration in the original water and the 

amount of water pumped through the resin are not provided. In this case, the sulfate concentration needs 

to be estimated after elution to be able to precipitate an appropriate amount of BaSO4 for the analysis. 

This is done by precipitating 2 mL of sample and comparing its turbidity with a sample series ranging 

between 5 mg/L and 30 mg/L, which is prepared ahead of time. All the bottles should be the same size 

and color for proper comparison. 

Interferences 

The δ34S of sulfate can be seriously altered if a water sample contains dissolved sulfide. The δ34S of 

sulfide can be as different as 65 ‰ from the δ34S of sulfate; therefore, trace oxidized sulfide could 

seriously alter the δ34S of sulfate. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 7 Effective: March 3, 2004
Troubleshooting and Bench Notes 

The most common problems with this analytical technique are (1) incomplete combustion, 

(2) leakage in the system, particularly in the EA, and (3) insufficient linearity of the IRMS. 

The fact that the melting point of the BaSO4 is 1580°C and the temperature of the reaction tube 

temperature is only 1020°C could create insufficient combustion. The “flash point” has a higher 

temperature, approximately 1800°C (because the tin oxidation reaction is exothermic); therefore, it is 

critical to create a sharp, sudden, bright, single flash. This can be done by coordinating (1) He pressure 

and flow rate, (2) oxygen pressure and flow rate, and (3) sample “start time.” The system is so sensitive 

that even a 1-second difference in the sample dropping time can make a difference in the brightness of the 

flash, peak shape, peak area, and, consequently, the δ34S result. The optimum set-up parameters of the 

RSIL EA are cycle = 100, oxy = 60 (O2 flow stops flowing into autosampler), sample start = 10, and 

sample stop = 40. The helium regulator is set for 150 kPa, and He flow setup is 95 mL/min, which 

actually measures 120 mL/min at the vent. The oxygen regulator is set for 150 kPa, and the oxygen flow 

rate is 54 mL/min at purge. The oxygen loop is 5 mL. Oven temperature of the GC is 90°C. Sample size 

is approximately 0.2 to 0.3 mg (BaSO4) (Révész, 1998). To improve analytical precision, 0.6 mg V2O5 is 

added to each sample (Yanagisawa and Sakai, 1983). 

Even a tiny leak can interfere with the result; it can create double peaks, an unstable analysis, and so 

forth. The high He flow rate makes the system more sensitive to leaks (Bernoulli principle). Leaks can 

cause uncontrollable changes in the flow rate, which could interfere in the quantitative combustion, in the 

peak shape, in the peak area, and consequently, in the δ34S value. Ash accumulation is also critical. 

Although tin oxide serves as a catalyst in the reaction, it also partially “clogs” the system, interfering with 

the flow rate, although not necessarily in a measurable manner. However, this assumes a nonrandom

interference that causes the shift in δ34S value. By frequently analyzing reference materials, this shift can 

be corrected. However, after approximately 50 samples (one carousel), it is advisable to remove the ashes 

(Révész, 1998). The leak-checking procedure is given in Appendix K. A leak is indicated in the IRMS 

when m/z 28 and 29 are high and the ratios of m/z 28, 32, and 40 (N2, O2, and Ar) reflect atmospheric 

compositions. Acceptable levels for m/z 28 and 29 are approximately 0.15 and 0.015 V, respectively, with 

typical IRMS settings. (See “Daily Checklist” in Appendix L.) 

The IRMS must be focused carefully. The analyst should start with the original factory setting. In the 

RSIL, the settings (in priority order) are as follows: Extraction = 7.00; X focusing = 4.8; Voltage = 8.00; 

Trap = 5.7; Electron = 7.8; Y1 focusing = 3.00; Y2 focusing = 3.8; X deflection = 6.4; Extraction = 5.6;

and X-focusing symmetry = 3. Emission current is critical. The higher it is, the higher the signal is but the 

poorer the linearity is. The IRMS is temperature sensitive; therefore, it must be operated in a temperaturecontrolled environment with all of the side panels on. The resistor–capacitor combination at the low-mass

cup is 3 × 108 Ω and 680 pF. At the high-mass cup, the combination is 3 × 1010 Ω and 5 pF. The 

instrument is capable of measuring m/z 64 and 66 simultaneously (fig. 3). 

An internal precision check needs to be conducted using the “Zero Enrichment” method (standard gas 

on/off 10 times), and it must give a standard deviation of ± 0.1 ‰ or better. The “Ratio Linearity” test 

must give 0.12 ‰/V or better linearity. An external precision check needs to be performed as needed, 

approximately every week or so; samples of the same amount need to be analyzed within ± 0.010 mg. The 

1–σ standard deviation must be ± 0.2 ‰ or better for n = 10. If either of these criteria has not been met, 

the IRMS cannot be used and must be refocused. 

Maintenance and Maintenance Records 

Routine maintenance is necessary for the upkeep of the IRMS vacuum system, including

(1) checking the pump performance from time to time, (2) changing the pump oil, and (3) changing the 

oil cartridge in each turbomolecular pump at 6-month intervals. Pump conditions, including date of oil 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 8 Effective: March 3, 2004
changes, problems, and repairs to the pump, are listed in the pump database (file path: LIMS 

C:\RSIL\vacuum pumps). Maintenance of the EA includes (1) changing the insertion tube every day 

(Appendix M), (2) changing the water trap approximately every 200 samples (Appendix N), (3) changing

reaction tubes approximately every 200 to 250 analyses (Appendix O), and (4) cleaning the sample 

carousel every week. The IRMS also requires a daily check (Appendix L). A logbook is kept for each 

IRMS, where notes of maintenance checks, history of normal settings, problems, and repairs are listed. 

Maintenance of ISODAT 2.0 includes importing (transferring) results from the ISODAT 2.0 database 

to the LIMS-LSI computer hard disk and the Data Back-Up computer hard disk (Appendix I). 

Sample Retention Time and Disposal 

Samples are retained in the RSIL for at least 4 months after reporting data. Samples are then 

discarded unless the submitter has requested that the samples be returned. 

The ISODAT sample files from the IRMS computer are kept indefinitely on two different hard disks 

of the Data Back-Up computer. Paper reports are kept for a few weeks. Analytical results from the IRMS 

are transmitted to LIMS-LSI and kept indefinitely. No data are entered by hand, and no manual 

calculations are performed on the data. 

Data Acquisition, Processing, Evaluation, Quality Control, and Quality 

Assurance 

Laboratory Information Management System for Light Stable Isotopes (LIMS-LSI) 

In the RSIL, the LIMS-LSI (Coplen, 2000) is used for data acquisition, processing, and evaluation. 

This system is a database program capable of (1) storing information about samples, (2) storing the results 

of mass spectrometric delta values of samples after importing from the ISODAT database, (3) calculating 

analytical results using standardized algorithms stored in a database, (4) normalizing delta values using 

isotopic reference materials, and (5) generating templates for convenient sample placement to facilitate 

loading of automated mass-spectrometer sample-preparation manifolds. With this system, the following 

can be achieved: (1) quality assurance (QA), (2) laboratory efficiency, (3) reduction of workload and 

errors owing to the elimination of retyping of data by laboratory personnel, and (4) a decrease of errors in 

data reported to sample submitters. This database provides a complete record of information on how 

laboratory reference materials have been analyzed and provides a record of what correction factors have 

been used. It provides an audit trail for the RSIL. 

Quality-Control (QC) Samples 

Samples are prepared and analyzed in batches—a maximum of 80 daily. Each batch contains 

approximately six reference materials at the beginning, four enriched in 34S, one with an intermediate 

concentration, and one depleted in 34S. One set of three (depleted, intermediate, and enriched in 34S) is 

analyzed for every 10 samples. The last analysis of a batch is one final set of the reference materials. All 

of these reference materials serve as QC samples. The preparation and analytical cost of these isotopic 

reference materials is the responsibility of RSIL. Both RSIL and NWQL monitor these results. Quarterly,

RSIL prepares a summary of results and makes them available to NWQL. 

Daily, the analyst (1) examines the computer printouts for indications of analytical problems, 

(2) determines the daily additive and expansion correction factors by the LIMS-LSI, and (3) applies 

corrections factors to isotopic data. These values with dates and analysis-number ranges are recorded 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 9 Effective: March 3, 2004
manually in the laboratory “δ34S Correction Factor” three-ring binder even though the data are already in 

the LIMS-LSI. After printing the list of isotopic results from the “Table of Samples in Progress,” the 

analyst reviews the results and determines which samples need to be analyzed a third time to achieve 

acceptable results (i.e., ∆δ ≤ 0.2 ‰). 

Acceptance Criteria for All QC Samples 

Acceptance criteria for QC samples are the same as acceptance criteria for the other samples. The 

rules are as follows: 

• If standard deviation is ≤ 0.2 ‰, use mean delta. 

• If there are three or more analyses, delete the outlier and recalculate. 

• If standard deviation of this recalculation is ≤ 0.2 ‰, use mean from this recalculation. 

• If none of the above is the case, the result is not accepted, and corrective action is required. 

Corrective Action Requirements 

If the analyst finds any problem with the daily reference-sample data, the analyst contacts the 

supervisor. This process requires an evaluation and reanalysis of certain samples to ascertain the origin of 

the problem. 

If samples do not give satisfactory results after three or more separate analyses, the analyst averages 

all the data and reports the mean value. Such analytical results are indicated with a comment, and the 

customer will be advised by e-mail or other means. If the sample was submitted through the NWQL, it is 

the responsibility of the customer to determine whether the data need to be qualified. If so, the NWQL 

will mark the result in USGS databases appropriately. 

Responsible Parties for All QA/QC Functions for Procedures Covered in RSIL SOPs

The analyst, with supervisory approval, is responsible for qualifying data and notifying customers. 

Data Management and Records 

In addition to evaluating daily sample analyses, every week an analyst evaluates the data project by

project, reports results to the customers, and files final project data reports in the laboratory

“Correspondence” binder (Appendix P). 

Health, Safety, and Waste-Disposal Information 

Applicable Health and Safety Issues 

Personal Protection 

Safety glasses and protective gloves are recommended whenever samples are handled, especially

when the samples are of biological origin. For other precautions and safety procedures, consult Material 

Safety Data Sheets (MSDS); they are on file in the laboratory; http://www.ilpi.com/msds/#Manufacturers

provides links to MSDSs of most chemical companies. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 10 Effective: March 3, 2004
Electrical Hazards 

Electrical systems must conform to the National Electric Code, National Fire Protection Association 

Code (NFPA 70-1971), and the American National Standards Institute (ANSI) Code (C1-1971). Consult

the U.S. Geological Survey’s Safety and Environmental Health Handbook (U.S. Geological Survey, 

2002). 

Shock hazards exist inside the instruments. Only an authorized service representative or an individual 

with training in electronic repair must remove panels or circuit boards where voltages are greater than 

20 V. The instruments require a third-wire protective grounding conductor. Three-to-two wire adapters 

are unsafe for these instruments. 

Chemical Hazards

The hazardous chemicals used in the process are Cr2O3 and Co3O4, which are used in the oxidation 

reaction tube, and V2O5, which is used to boost combustion. Sometimes the reaction tube cracks, and the 

packing material leaks out. When this happens, protective gloves and a full-face mask are required during 

the cleanup process. All the materials, including gloves and any cleaning towels, need to be collected in a 

plastic bag and disposed of as hazardous waste. When handling V2O5, protective gloves and a full-face 

mask also are required. All samples must be carefully inspected upon receipt for obvious indications of 

hazards. 

The SO2 reference gas is colorless and has a suffocating odor. Exposure to SO2 can cause respiratory

tract burns. Therefore, an appropriate ventilation unit must be installed in the ConFlo unit. A leak test on 

the tank of gas and the line carrying SO2 to the ConFlo must be performed routinely. 

Gas Cylinder Handling

Compressed gas cylinders must be handled and stored according to the Safety and Environmental 

Health Handbook (U.S. Geological Survey, 2002). Each cylinder must be (1) carefully inspected when 

received; (2) securely fastened at all times with an approved chain assembly or belt; (3) capped at all 

times when not in use; (4) capped when transported; (5) transported only by a properly designed vehicle 

(hand truck); and (6) stored separately with other full, empty, flammable, or oxidizing tanks of gas, as 

appropriate. 

Specific Waste-Disposal Requirements 

The chemicals Cr2O3, Co3O4, and V2O5 must be collected in a separate, closed container. Ba from the 

waste BaCl2 solution must be precipitated with Na2SO4 solution, and the solid BaSO4, along with the 

other hazardous chemicals, must be given to the safety, health, and environment officer for disposal. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 11 Effective: March 3, 2004
Revision History 

Publication Series and Series Number: Techniques and Methods 10-C8 (Book 10, Section C, Chapter 8) 

Publication Title: Determination of the δ(

34S/32S) of Low-Concentration Sulfate in Water: RSIL Lab Code 

1949 

Publication Authorship: Révész, Kinga, and Qi, Haiping 

First Version and Date of First Release: January 2006 

Current Version and Date of Current Release: July 2007 

Summary of Product Components 

Component Description 

Last Revised 

In Publication Version 

Date of 

Last Revision 

List of Revisions (latest version first): 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 12 Effective: March 3, 2004
References Cited 

Brenna, J. T., Corso, T. N., Tobias, H. J., and Caimi, R. J., 1997, High-precision continuous-flow isotoperatio mass spectrometry: Mass Spectrometry Reviews, v. 16, p. 227–258. 

Carmody, R. W., Plummer, L. N., Busenberg, E., Coplen, T. B., 1998, Methods for collection of

dissolved sulfate and sulfide and analysis of their sulfur isotopic composition: U. S. Geological Survey

Open-File Report 97-234, 91 p. 

Clark, I., and Fritz, P., 1997, Environmental Isotopes in Hydrogeology: Levis Publishers , 328 p. 

Coplen, T. B., 2000, A guide for the laboratory information management system (LIMS) for light stable 

isotopes—Version 7 and 8: U. S. Geological Survey Open-File Report 00-345, 121 p. 

Coplen, T. B., and Krouse H. R., 1998, Sulfur isotope data consistency improved: Nature, v. 392, p. 32. 

Krouse, H. R., and Coplen, T. B., 1997, Reporting of relative sulfur isotope-ratio data: Pure and Applied 

Chemistry, v. 69, p. 293–295. 

Révész, K., 1998, Carbon and nitrogen isotope ratios of organic and inorganic bulk samples: Instrument 

performance and intercalibration: The 5th Canadian Continuous-Flow Isotope-ratio Mass Spectrometry

Workshop, Ottawa Ontario, August 16–19, 1998. 

Robinson, B. W., 1995, Sulfur Isotope Standards: Reference and intercomparison materials for stable 

isotopes of light elements, Proceedings of a consultants meeting held in Vienna, 1–3 December, 1993, 

IAEA-TECDOC 825, p. 39–45. 

U.S. Geological Survey, 2002, USGS Handbook 445-3-H, Safety and Environmental Health Handbook,

435 p. 

Yanagisawa, F. and Sakai, H., 1983, Thermal decomposition of barium sulfate—vanadium pentoxide—

silica glass mixtures for preparation of sulfur dioxide in sulfur isotope ratio measurements: Analytical 

Chemistry, v. 55, p. 985–987. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 13 Effective: March 3, 2004
Appendix A. Step-by-Step Procedure to Log-In Samples to LIMS-LSI 

1. For samples submitted through NWQL: 

a. Match up information on sample bottles with information on ASR forms by spreading out ASR 

forms and placing each bottle on its respective ASR form. Check for broken bottles. 

b. Assign NWQL #s based on the Julian date of the Monday following the submission date. Check 

note on bulletin board for “Next NWQL #.” Write NWQL #s on ASR forms, then update “Next 

NWQL #” on bulletin board. 

c. Use “New Project Log-In” in LIMS-LSI to assign S-#s; field IDs are the Station IDs. Submission 

date is the date samples are logged in. 

d. Enter all ASR information into LIMS-LSI, sample by sample. 

e. Print out two Project Reports, Labels (two for each sample), and Sample Range forms. 

f. Put a label on a sample bottle and on the corresponding ASR form; crosscheck Field IDs between 

bottles and ASR forms. 

g. Make one photocopy of each ASR form. 

h. Enter S-# range into the appropriate template. 

i. Proofread information on Sample Range forms against ASR forms (recruit help if necessary). 

Make corrections in LIMS-LSI, if necessary and print out corrected Sample Range Forms. Initial 

and date both Project Reports to indicate that proofreading is complete. 

j. In LIMS-LSI, save NWQL Headings to a diskette. 

k. In ISOTOPES e-mail on the common-use PC, copy headings into new message from diskette by

opening headings-file in Notepad and copying/pasting to new message. Print copy of headings 

and e-mail to each project chief for information review and NWQL [Attn: Jeanne Hatcher 

(jhatcher@usgs.gov)].

l. Mail copies (not originals) of ASR forms and corrected Sample Range forms to NWQL [National 

Water Quality Laboratory, Attn: Jeanne Hatcher, U.S. Geological Survey, P.O. Pax 25708, MS

407, Building 95, Denver Federal Center, Denver, CO 80225-0608 (Tel: 303-236-3481)].

Envelope should be mailed every Friday.

m. Punch holes in original ASRs and put in “Central Lab” binder along with project reports and date 

on piece of tape. Punch holes in NWQL headings and other project report and place in “Samplesin-Progress” binder. 

n. Add samples to the “Table of Samples to Be Analyzed” in LIMS-LSI. 

i. Click the “Projects” button of LIMS-LSI. 

ii. Select the project that was logged in. 

iii. Click the “Templates” button. 

iv. Select “EA for S.” 

v. Click “Add” and close LIMS-LSI. 

o. Put samples in cabinets for storage until analyzed. 

2. For samples submitted directly to RSIL:

a. For sample submitter: 

i. Download “RSIL Excel Worksheet” from RSIL website at http://isotopes.usgs.gov/. 

ii. Fill out the requested sample information. 

iii. Send diskette and a hard copy along with the samples. 

b. For RSIL personnel: 

i. Match up information on sample bottles with submitted “Excel Worksheet.” 

ii. Enter all Excel Worksheet information into LIMS-LSI by loading diskette. Submission date is 

the date samples are logged in. 

iii. Use “New Project Log-in” in LIMS-LSI to assign S-#s; field IDs are the Station IDs. 

iv. Print out one Project Reports and container labels (one for each sample). 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 14 Effective: March 3, 2004
v. Put a label on a sample bottle and crosscheck Field IDs between bottles and Excel Worksheet 

forms. 

vi. Enter S-# range into the appropriate template. 

vii. Punch holes in original Excel Worksheet and all the information for the project and put in 

“Samples-in-Progress” binder. 

viii. Add samples to the “Table of Samples to Be Analyzed” in LIMS-LSI.

1. Click the “Projects” button of LIMS-LSI. 

2. Select the project that was logged in. 

3. Click the “Templates” button. 

4. Select “EA for S.” 

5. Click “Add” and close LIMS-LSI. 

ix. Put samples in cabinets for storage until analyzed. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 15 Effective: March 3, 2004
Appendix B. Step-by-Step Procedure to Prepare Resin for Field 

Collection and Elute Sulfate from Resin after Field Collection 

1. Prepare resin cartridge for field collection: 

a. Clean “sulfate-free” commercially available anion (Amberlite IRA-400 (RN(CH3)3 + Cl–

) resin: 

i. Add DIW to 500 g of resin and load it into a 6-cm × 50-cm column, cover with 2 cm of 

quartz wool. Make sure there are no air bubbles in the resin. 

ii. Prepare 3 M KCL solution: 

(1) Weigh 223.74 g KCl in 1000 mL volumetric flask; add DIW to male 1000 mL. 

(2) Pour 2 L of 3 M KCl through the resin at a flow rate of 10 mL/min. 

(3) Rinse resin with 3 L of DIW. 

2. Distribute clean resin into 1.5-cm × 15-cm column, plugged with 1 cm of glass wool to hold the resin 

in place. 

3. Elute sulfate from resin: 

a. Open the drying tube at one end, remove glass wool and transfer the resin to a 1.5-cm × 30-cm

glass column by DIW. Put the glass wool on top of the resin. Rinse with 20 mL DIW. Make sure 

there are no air bubbles in the column. 

b. Place a 250-mL beaker beneath the column and close the stopcock. 

c. Measure 150 mL of 3 M KCl solution and pour it into the column. 

d. Open the stopcock, and let the solution elute the resin at a flow rate of 3 mL/min. 

e. Collect last 1 mL eluant in a 5-mL beaker that contains a few drops of BaCl2 to check the 

completion of elution of SO4

2–. If small amount of BaSO4 precipitate can be observed, elute the 

column with an additional 10 mL of 3 M KCl. Repeat this step until no BaSO4 precipitate can be 

observed. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 16 Effective: March 3, 2004
Appendix C. Step-by-Step Procedure to Precipitate BaSO4

1. Acidify an amount of water to yield 50 mg of BaSO4 with four drops of 1 M HCl to convert carbonate 

to CO2 gas. (The 1 M HCl can be prepared by pouring 40.4 mL of 38 % commercial HCl solution 

into 500 mL of DIW.) 

2. Add H2O2 to oxidize dissolved organic sulfur and any resin in case it leaked trough during elution: 

a. Add 6 mL of 6 % H2O2 to sample. (The 6 weight % H2O2 can be prepared by adding 95.5 mL of 

30 % H2O2 to 404.5 mL of DIW.) Put beaker with sample onto the hot plate with stir bar and set 

temperature controller to 200°C. Cover the beaker with a watch glass. 

b. Remove all the samples from the hot plate after 45 min. 

3. Precipitate sulfate: 

a. Add 5 mL of 20 % BaCl2 solution. (The 20-weight % BaCl2 can be prepared by dissolving 

117.3 g BaCl2·2H2O solids in 441 mL DIW.) Let the solution cool slowly to 50°C or lower, 

usually overnight. 

4. Filter BaSO4 precipitate: 

a. Place a 0.2-μm Isopore PCM filter paper into an empty, clean, labeled sample bottle. Weigh the 

sample bottle with filter paper without the cap. Record weight on the Dissolved Sulfate 

Precipitation form. 

b. Set up filtration apparatus: 

i. Clean filtration apparatus equipment thoroughly with DIW and then set up the filtration 

apparatus. 

ii. Put a coarse-fritted glass support base (with stopper) onto a 1000-mL filtering glass flask. 

iii. Place tubing accordingly in a peristalsis pump. Attach the vacuum end of the tubing to the 

1000-mL filtering glass flask. 

iv. Moisten the coarse-fritted glass support base with some DIW. Place a 0.2-μm Isopore PCM 

filter paper (shiny side face up) centered on the coarse-fritted glass support base. 

v. Place a 300-mL graduated funnel onto the coarse-fritted glass support base and then clamp 

the two together with an aluminum clamp. 

vi. Turn peristaltic pump on. Add a small amount of DIW into the 300-mL graduated funnel to 

check for any leaking. 

c. Pour sample into 300-mL graduated funnel until the entire sample has filtered into the 1000-mL 

flask. 

d. Turn off pump. Remove the tubing attached to the 1000-mL filtering glass flask. Take off the 

clamp and remove the 300-mL flask from the coarse-fritted glass support base. 

e. Remove filter paper with precipitate and put it back in its container. 

f. Take the coarse-fritted glass support base off the 1000-mL filtering glass flask. 

g. Test the filtrate for sulfate by adding BaCl2 solution. If no turbidity shows, discard the filtrate. If 

there is some turbidity, filter the solution again on a different filter paper and combine the two 

precipitates. 

h. Clean all of apparatus thoroughly. Repeat procedure for the remaining samples. 

5. Dry each precipitate at 90°C in an oven overnight. 

6. Weigh the sample bottle with filter paper that has BaSO4 on it and record it on the Dissolved Sulfate 

Precipitation form. 

7. Scrape off the dried BaSO4 from filter into the vial and homogenize the sample with a spatula in the 

vial. Store them on the shelf for isotopic analysis. Discard the filter. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 17 Effective: March 3, 2004
DISSOLVED SULFATE PREPARATION FORM 

S-# Date 

NWQL-# Project Chief 

Field ID Location 

Reported SO4

2– concentration: 

Volume submitted: 

Volume used 

PRE-FILTRATION Comments: 

Pore diameter of polycarbonate membrane: 

ACIDIFICATION: (pH = 2.75 to 3.25) 

pH before acidification: approx._______ mL HCl used 

pH after acidification: 

Began heating sample at: __________ 

OXIDATION: 

Oxidizing agent: 6 mL 6 % H2O2 Comments: 

volume used: 

PRECIPITATION: 

Approx. ________ mL BaCl2 added at: __________ Comments: 

 

FILTRATION AND YIELD: 

Use 0.2 μ-pore-diameter polycarbonate membrane: __________ 

 

weight of PCM, BaSO4

, dish 

 Yield/Concentration: 

weight of PCM, dish 

weight of BaSO4 

[ ] 1 mL of 20 weight % BaCl2 added to ensure complete precipitation of BaSO4. 

[ ] No further precipitation observed after 10 min; precipitation complete.

[ ] Continued precipitation; further filtering required. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 18 Effective: March 3, 2004
Appendix D. Step-by-Step Procedure to Generate an Excel Sample

Workbook or to Print a Template and a Samples-to-Be-Analyzed List 

Excel Sample Workbook 

1. Use default template and add samples to be analyzed.

2. Fill the appropriate amount in the cells of the rows labeled “Set weight mg.” 

3. Print first worksheet in workbook. 

4. Write the tray ID and the date on both the diskette and paper template. 

5. Put them near the balance. 

Template 

1. Use “Print Template” in LIMS-LSI. 

2. Select “appropriate template” for EA and “Delta Plus” IRMS. 

3. Select “New Template” (dialog box informs you how many samples are waiting to be analyzed). 

4. Click “OK.” 

5. Click “Print.” 

6. Insert diskette to receive sample headings. 

7. Click “OK.” 

8. Write the day of the week that these samples should be analyzed on both the diskette and paper 

template. 

9. Put them near the balance. 

10. Exit LIMS-LSI. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 19 Effective: March 3, 2004
Worksheet 1. Weighing template.

[International reference materials are in bold font.]

1 2 3 4 5 6 7 8 9 10 11 12

Our Lab ID S-97 S-97 S-97 S-97 S-1301 S-1302 S-9031 S-9031 S-9032 S-9032 S-9033 S-9033

A Set weight mg 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual weight,

mg 

0.3 0.29 0.31 0.31 0.304 0.298 0.299 0.302 0.305 0.303 0.305 0.303

Comment NBS-127 NBS-127 NBS-127 NBS-127 IAEA-SO-5 IAEA-SO-6

Our Lab ID S-9034 S-9034 S-9035 S-9035 S-97 S-1301 S-1302 S-9037 S-9037 S-9038 S-9038 S-9039

B Set weight mg 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual weight,

mg 

0.301 0.302 0.295 0.303 0.299 0.295 0.301 0.299 0.293 0.304 0.301 0.304

Comment NBS-127 IAEA-SO-5 IAEA-SO-6

Our Lab ID S-9039 S-9040 S-9040 S-9041 S-9041 S-97 S-1301 S-1302 S-9043 S-9043 S-9044 S-9044

C Set weight mg 0.3 0.3 0.3 0. 3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual weight,

mg 

0.301 0.301 0.295 0.306 0.297 0.302 0.3 0.305 0.304 0.297 0.304 0.301

Comment NBS-127 IAEA-SO-5 IAEA-SO-6

Our Lab ID S-9045 S-9045 S-9046 S-9046 S-9047 S-9047 S-97 S-1301 S-1302 S-9049 S-9049 S-9050

D Set weight mg 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual weight,

mg 

0.295 0.303 0.32 0.299 0.298 0.296 0.303 0.305 0.305 0.297 0.302 0.296

Comment NBS-127 IAEA-SO-5 IAEA-SO-6

Our Lab ID S-9050 S-9051 S-9051 S-9052 S-9052 S-9053 S-9053 S-97 S-1301 S-1302

E Set weight mg 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Actual weight,

mg 

296 0.296 0.295 0.299 0.305 0.305 0.299 0.302 0.297 0.304

Comment NBS-127 IAEA-SO-5 IAEA-SO-6

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 20 Effective: March 3, 2004
Worksheet 2. Samples to be analyzed.

[International reference materials are in bold font]

Line Identifier Port Comment Amount Amt Unit 

1 S-97 A1 NBS-127 0.3 mg

2 S-97 A2 NBS-127 0.29 mg

3 S-97 A3 NBS-127 0.31 mg

4 S-97 A4 NBS-127 0.31 mg

5 S-1301 A5 IAEA-SO-5 0.304 mg

6 S-1302 A6 IAEA-SO-6 0.298 mg

7 S-9031 A7 0.299 mg

8 S-9031 A8 0.302 mg

9 S-9032 A9 0.305 mg

10 S-9032 A10 0.303 mg

11 S-9033 A11 0.305 mg

12 S-9033 A12 0.303 mg

13 S-9034 B1 0.301 mg

14 S-9034 B2 0.302 mg

15 S-9035 B3 0.295 mg

16 S-9035 B4 0.303 mg

17 S-97 B5 NBS-127 0.299 mg

18 S-1301 B6 IAEA-SO-5 0.295 mg

19 S-1302 B7 IAEA-SO-6 0.301 mg

20 S-9037 B8 0.299 mg

21 S-9037 B9 0.293 mg

22 S-9038 B10 0.304 mg

23 S-9038 B11 0.301 mg

24 S-9039 B12 0.304 mg

25 S-9039 C1 0.301 mg

26 S-9040 C2 0.301 mg

27 S-9040 C3 0.295 mg

28 S-9041 C4 0.306 mg

29 S-9041 C5 0.297 mg

30 S-97 C6 NBS-127 0.302 mg

31 S-1301 C7 IAEA-SO-5 0.3 mg

32 S-1302 C8 IAEA-SO-6 0.305 mg

33 S-9043 C9 0.304 mg

34 S-9043 C10 0.297 mg

35 S-9044 C11 0.304 mg

36 S-9044 C12 0.301 mg

37 S-9045 D1 0.395 mg

38 S-9045 D2 0.303 mg

39 S-9046 D3 0.32 mg

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 21 Effective: March 3, 2004
Line Identifier Port Comment Amount Amt Unit 

40 S-9046 D4 0.299 mg

41 S-9047 D5 0.298 mg

42 S-9047 D6 0.296 mg

43 S-97 D7 NBS-127 0.303 mg

44 S-1301 D8 IAEA-SO-5 0.305 mg

45 S-1302 D9 IAEA-SO-6 0.305 mg

46 S-9049 D10 0.297 mg

47 S-9049 D11 0.302 mg

48 S-9050 D12 0.296 mg

49 S-9050 E1 0.296 mg

50 S-9051 E2 0.296 mg

51 S-9051 E3 0.295 mg

52 S-9052 E4 0.299 mg

53 S-9052 E5 0.305 mg

54 S-9053 E6 0.305 mg

55 S-9053 E7 0.299 mg

56 S-97 E8 NBS-127 0.302 mg

57 S-1301 E9 IAEA-SO-5 0.297 mg

58 S-1302 E10 IAEA-SO-6 0.304 mg

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 22 Effective: March 3, 2004
Appendix E. Step-by-Step Procedure for Weighing and Storing Samples 

1. Samples should be homogenized and dried. 

2. Insert Template diskette in the computer connected to the microbalance. 

3. Condition balance (this step should be done once a day): 

a. Place empty capsule on balance and close door. Wait for reading to stabilize (the “mg” on the 

display appears). Tare the balance. 

b. Remove and replace capsule and make sure the stabilized weight is 0.000 mg. 

c. Repeat these steps until the balance is stable. 

4. Remove capsule from balance, add sample and weigh the filled capsule. Repeat until you have the 

desired weight (300 ± 10 μg). 

5. Enter sample weight on the template. 

6. Add 600 μg ± 100 μg of V2O5 to sample. 

7. Fold cup, secure sample in it. 

8. Repeat steps 4 to 7 for every sample. 

9. Note: 

a. Do not cross-contaminate samples. 

b. Make sure the spatula and sample area are cleaned using Kimwipes between each sample. 

c. Always allow balance to stabilize before removing capsule. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 23 Effective: March 3, 2004
Appendix F. Step-by-Step Procedure for Zero Blank Auto Sampler 

Operation 

1. Before opening lid, make sure the isolation valve (between sample chamber and reaction tube) is 

closed (arrow toward you), and make sure the He purge isolation valve (on the left) is closed. 

2. Open the purge vent on the top of the auto sampler to vent the sample chamber. 

3. Release the three fittings holding the lid close and open the lid. 

4. Place your samples and close the lid. Load 49 samples for 50-position carousel; leave the first hole 

empty. 

5. Secure the lid with three bolts. Start all three bolts, and then lightly tighten two at a time, moving 

around the lid until they are all completely tight. 

6. Open He purge isolation valve (slide to left); purge the sample chamber for 5 min at He flow rate of 

298 mL/min. Make sure the purge vent valve (on top) is open. Press your finger on top of the vent 

valve for 2 s, then release; you should hear the sound of a pressure release. 

7. Close the He purge vent valve (screw down), wait for 2 min for gas pressure at sample chamber and 

He flow rate to stabilize. Close He purge isolation valve. 

8. Open isolation valve (arrow toward up).Wait for 2 min for stabilized baseline. Normally when the 

emission current set at 0.54 mA/0.48 mA, with He carrier flow rate of 90 mL/min, one should see m/z 

28 on cup 1 at approximately 10 mV, m/z 29 on cup 2 at approximately 8 to 12 mV, and m/z 30 on 

cup 3 at approximately 140 mV to 1 V (Appendix L).

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 24 Effective: March 3, 2004
Appendix G. Step-by-Step Procedure to Add Sample Information to

Sequence Table 

1. Insert diskette with “Weighing Template” on it. 

2. Open “Sequence File” under “EA configuration.” 

3. Open “Weighing Template” in Excel. 

4. “Copy” and “Paste” the list of Sample ID, sample weight from template to sequence table. 

5. Select appropriate “method” for each sample. 

6. Define reference line and blank line. 

7. Start. 

8. Give Folder Name: Comment. 

a. Select pre: “Date.” 

9. Give File Name: leave it empty

a. Select pre: “Analyzes #.” 

b. Select post: “Identifier 1.” 

c. Select: “Print Result.” 

10. Click OK. 

11. Wait for first sample to be analyzed. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 25 Effective: March 3, 2004
Appendix H. Step-by-Step Procedure to Retrieve Data from ISODAT 2.0 

for LIMS-LSI and for Data Back-Up 

1. For LIMS-LSI: 

a. Select “Result” in ISODAT 2.0. 

b. Select the result folder you wish to export data from.

c. Select all the individual analyses you want to retrieve by right clicking the selected file. 

d. Select “Reprocess.” 

e. Assign a file name. 

f. Add export template previously designed.

g. Open. 

h. Click OK. (Reprocessing takes 1–2 min.) 

i. Open Excel. 

j. Find the file you reprocessed (E-drive, Finnigan, ISODAT 2.0, Global, User, CONFLO II, 

Interface, Result: File name). 

k. Open it in Excel. 

l. Save as: “A” drive. Keep in Lotus format. 

m. Define all reference peaks by adding #1 under column “Is Ref.?.” 

n. Now the file can be imported to LIMS-LSI. 

2. For Data Back-Up Computer: 

a. Go to Windows explorer in ISODAT 2.0 computer. 

b. Find the drive where the data are (D). 

c. Choose: “Finnigan.” 

d. Choose: “User.” 

e. Choose the inlet system where you have data (Gas Bench or EA). 

f. Choose “Result folder.” 

g. Transfer data to Zip disk or “memory stick.” 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 26 Effective: March 3, 2004
Appendix I. Step-by-Step Procedure to Transfer Data to LIMS-LSI, to 

Transfer Data to Back-Up Computer, and to Reevaluate Old Data

1. Transfer data to LIMS-LSI: 

a. Start LIMS. 

b. Choose “Import Analysis.”

c. Choose IRMS “Delta Plus.” 

d. Click “Import.” 

e. Select the file that will be imported. 

f. Select columns containing δ34S data. Check the boxes to import these two columns. 

g. Click Import. Note: Sample ID, sample weight, Peak Area, Analysis # are automatically imported 

to LIMS-LSI. 

2. Transfer data to Data Back-Up computer: 

a. Go to Windows Explorer in the Data Back-Up computer. 

b. Find the drive your back ups are stored. 

c. Choose: “RSIL.” 

d. Choose: “Mass. Spec. Analysis Back Up.” 

e. Choose: “P.” (Stands for DeltaPlus IRMS). 

f. Under that folder create a new folder. The name of the folder should be the date range when those 

analyses were done that you want to back up. 

g. Transfer data to that folder. 

h. Make back ups every 2 weeks or so, as required. 

3. Reevaluate old data: 

a. Find your samples in the Data Back-Up computer. 

b. Transfer data by a Zip disk or “memory stick” to the computer where a virtual version of 

ISODAT 2.0 is installed. 

c. Reevaluate your data. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 27 Effective: March 3, 2004
Appendix J. Step-by-Step Procedure to Determine and Apply Correction 

Factors and Evaluate Data 

1. Open “Correction Factors and Normalization Equations” in LIMS-LSI. 

2. Select the IRMS and isotope, such as “P (Delta Plus) for 34S.” 

3. Select “Query.” 

4. Double click on the last sample analyzed on that day.

5. Evaluate data of the reference materials. 

6. Choose “Normalize with all References.” 

7. Accept “Expansion Correction and Additive Correction factors.” 

8. Print out correction factor sheet. 

9. Report daily reference values and correction factors along with date and range of analysis number to 

the “EA” binder. 

10. Go back to LIMS-LSI main menu by closing open windows. 

11. Choose “Print Samples in Progress,” 

a. Open “Sample in Progress.” 

b. Choose appropriate isotope. 

c. Choose appropriate prefix (W for water, N for nitrogen, S for sulfur). 

d. Put in sample ID range from “Samples-to-Be-Analyzed” sheet. Click Print. 

12. Review results; determine repeats. 

13. Put repeats back to “Table of Samples to Be Analyzed.” 

a. Go back to LIMS-LSI main menu. 

b. Open “Print Templates.” 

c. Select appropriate template name for the IRMS with which the samples are analyzed. 

d. Find the sample in the “List of Samples.” 

e. Change “Repeats” from 0 to 1. 

f. Close windows and exit LIMS-LSI. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 28 Effective: March 3, 2004
Appendix K. Step-by-Step Procedure to Check Elemental Analyzer for 

Leaks 

1. Close the VENT carrier output using the proper cap (provided). 

2. Adjust the He pressure to 150 kPa (regulator is on the front central panel), wait 3 min to equilibrate 

gas in the system. 

3. Close He inlet valve by turning the above regulator counter clockwise. 

4. If the gauge needle does not move, there is no leak. 

5. If the gauge needle moves, indicating the lost of pressure, there is a leak in the system. The 

decreasing pressure rate accounts for the degree of leakage. 

6. Locate the leak by separating and testing the system segment by segment, using the He detector. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 29 Effective: March 3, 2004
Appendix L. Daily Checklist 

Analyst in charge: ______________________Date: ______________________

Weekly: 

1. Change working reference gas tank and He gas tank if the pressure is < 500 psi. Order new ones for a 

spare; reference gas is SO2 ANHY by Matheson, He carrier is zero grade. O2 gas is research grade. 

2. Change water and CO2 trap after approximately 200 samples or when it is necessary. 

3. Check and clean autosampler carousel. 

4. Change the reaction tube after approximately 200 samples or when it is necessary. 

THESE ITEMS ARE TO BE CHECKED OFF AS YOU CHECK THEM DAILY! 

1. Check He, O2, and reference gas flow. [ ] 

2. Check EA reaction-tube temperature (1020 °C). [ ]

3. Change insertion tube (ash-collector liner) in the reaction tube. [ ]

4. Check background masses. [ ]

Typical Background at N2/CO2 Configuration 

Emission Current: 0.54 mA/0.48 mA 

Cups Mass Intensity (V) Mass Intensity (V) Mass Intensity (V) Resistor (Ω) Capacity (pF) 

1 28 0.010 44 0 64 0.002 3 × 108680 

2 29 0.007 45 0 65 0.002 3 × 1010 5 

3 30 0.140 46 0.002 3 × 1011 2 

5. Perform Ref on/off method three times to stabilize IRMS. [ ]

6. Check peak center. If it is off default value by more than 50, do mass calibration. [ ]

7. Analyze Ref on/off method 10 times to stabilize IRMS (standard deviation should be better than 

±0.1 ‰). [ ]

Optimal ConFlo Pressure Setting 

SO2 (bar) 

SO2 signal (V) Mass 66 on Cup 2 

0.50 3.000

8. Check paper in printer. [ ]

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 30 Effective: March 3, 2004
Appendix M. Changing the Insertion Tube 

The insertion tube needs to be changed before a template is run. 

1. Manually close needle valve near the ion source. 

2. On the menu of the Model 2500 EA under “Spc. Fun.,” choose “Std By” and press “enter.” The O2

and He should be turned off. 

3. Unscrew the metal seals under the sample carousel to access the reaction tube. 

4. Using the heat protective glove and the wire tool, remove the insertion tube from the reaction tube 

and place in the metal can. Be aware that the tube will be very hot! 

5. Insert clean tube that has 0.5 cm of quartz wool packed on the bottom and tap it down with the wire 

tool. 

6. Replace the carousel and tighten the metal seals with a wrench. 

7. Turn the O2 and He back on by pressing “enter” and return the screen to the temperature readout by 

pressing “Spc. Fun.” 

8. Open the needle valve. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 31 Effective: March 3, 2004
Appendix N. Changing the Water Trap 

Change the water trap after every 200 samples. 

1. Retrieve quartz turnings, quartz wool, magnesium perchlorate, and a clean water trap from Delta

Plus

supplies. 

2. Under a hood, pack one end of the clean water trap with 1 cm of quartz wool. 

3. On a piece of wax paper, create a mix of approximately 70 % magnesium perchlorate and 30 % 

quartz turnings, pack the mix into the water trap tube, leaving 1 cm of empty space. 

4. Pack the open end of the water trap with quartz wool. 

5. Unscrew the red plastic ends from the used water trap and replace it with the clean water trap; be sure 

to replace the rubber O-rings on the ends of the clean water trap and tighten the red ends. 

6. Insert the plug into the vent and watch for any decrease in pressure to check for a leak in the system. 

If everything looks acceptable after 5 min, replace the vent line. 

7. Under the “Spc. Fun.” menu of the model 2500 EA, choose “CNT” (counter) and zero “D,” to set 

back the water-trap counter. 

8. Clean the water trap by pushing all the mixture out of the tube into the trash can and use a clean 

cotton swab to wipe out the inside of the tube. Rinse the tube with DIW, and dry it in the oven. 

Return this tube to the water trap bag in the drawer. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 32 Effective: March 3, 2004
Appendix O. Changing the Reaction Tube 

The reaction tube should be changed approximately every 200 to 250 samples. 

1. Manually close the needle valve near the ion source. 

2. Turn the Model 2500 EA to “Std By” with both gases off. 

3. Lower the reaction tube temperature to less than 900 °C. 

4. Retrieve the reaction tube from the cabinet. 

5. Insert the insertion tube into the top of the reaction tube; there will already be a plastic tube in the 

reaction tube that should be removed. The bottom of the reaction tube has copper in it. 

6. Place a black O-ring on the top of the reaction tube. Make sure that all O-ring connections are clean 

and free of any dust. 

7. Loosen the top metal seal and remove the bottom metal seal. Go back and completely remove the top 

seal. It will be very hot! Use oven gloves! 

8. Remove quartz reaction tube and place in metal can, place clean reaction tube in column. Make sure 

the O-ring is clean; then replace the top. 

9. On the bottom, put on the metal piece with the metal O-ring first and then add the clean rubber Oring. Raise the bottom portion and screw together. Then, tighten the connection with wrenches, and 

put the metal support back in place. 

10. Turn the gases back on; then, go to “CNT” in the menu under “Spc. Fun.” Set to zero the counter of 

the reaction tube “B.” 

11. Insert the plug into the vent and close the He supply. Watch for any decrease in the pressure to check 

for a leak in the system. If everything looks okay after 3 min, open the He supply and replace the vent 

line. 

12. Open the needle valve. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 33 Effective: March 3, 2004
Appendix P. Step-by-Step Procedure to Report Data 

1. Open “Store Samples in Progress” in LIMS-LSI. 

2. Choose the appropriate isotope. 

3. Choose sample ID range from “Sample in Progress” print out. 

4. Store data. 

5. Go back to the LIMS-LSI main menu. 

6. Open “Project” and find the appropriate project in the list. 

7. Select “Print Report” and check whether the project report contains all the results. If not, search for 

the missing results in the database. 

8. Select “Results,” transfer data in Excel format or (and) text format to a diskette, and report data to 

customer through e-mail. 

9. Click “Print Report” to print a project report and put it in the “Correspondence” binder along with all 

other documents in the “Samples In Progress” binder that are related to this project. 

10. If the samples were submitted through the NWQL, click “NWQL Export” and transfer data in NWQL 

format to a disc; report these data to the NWQL by e-mail. Print a copy of the NWQL export file and 

save in the “Correspondence” binder with the project report printed in the step above. 

Prepared by: Kinga Révész and Haiping Qi RSIL SOP: 1949

Approved by: T. B. Coplen Page 34 Effective: March 3, 2004