SPECIAL REPORT 95-14

Rapid Screening of Metals Using

Portable High-Resolution X-Ray

Fluorescence Spectrometers

Alan D. Hewitt April 1995
Abstract

Analysis of copper, zinc, arsenic, lead, chromium, cobalt, nickel, mercury,

thallium, selenium, silver, antimony, cadmium, tin, and barium was performed

on soils and other particle matrices using two field-portable high-resolution

X-ray fluorescence spectrometers (XRF). Quantitative determinations were based

on fundamental parameter analysis and a second method that relies on analyte

response factors and uses the Compton Kα incoherent backscatter peak for

matrix normalization. These two methods of instrumental analysis require only

a few reference materials and are relatively insensitive to sample matrix composition. This study assessed the capability of these two rapid XRF analysis

methods by determining metal concentrations in reference materials, field

samples, and laboratory spiked soils. With the exception of nickel, cobalt, and

chromium, concentrations within 50% of the expected values were consistently obtained at and below 1000 μg/g.

For conversion of SI units to non-SI units of measurement consult ASTM

Standard E380-93, Standard Practice for Use of the International System

of Units, published by the American Society for Testing and Materials,

1916 Race St., Philadelphia, Pa. 19103.

This report is printed on paper that contains a minimum of 50% recycled

material.
Special Report 95-14

Rapid Screening of Metals Using

Portable High-Resolution X-Ray

Fluorescence Spectrometers

Alan D. Hewitt April 1995

Prepared for

U.S. ARMY ENVIRONMENTAL CENTER

SFIM-AEC-ET-CR-95039

Approved for public release; distribution is unlimited.

US Army Corps


of Engineers

Cold Regions Research &


Engineering Laboratory
PREFACE

This report was prepared by Alan D. Hewitt, Research Physical Scientist, Geological

Sciences Division, Research and Engineering Directorate, U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, New Hampshire.

Funding for this work was provided by the U.S. Army Environmental Center, Martin H.

Stutz, Project Monitor. The author thanks Dr. T.M. Spittler for suggesting the response

factor/Compton Kα peak normalization method of analysis, Scott Clifford for providing

the field samples, and Thomas Ranney and Dr. Thomas F. Jenkins for critical review of the

text.

This publication reflects the views of the author and does not suggest or reflect policy,

practices, programs, or doctrine of the U.S. Army or of the Government of the United

States.

The contents of this report are not to be used for advertising or promotional purposes.

Citation of brand names does not constitute an official endorsement or approval of the use

of such commercial products.

ii
CONTENTS

Page

Preface ................................................................................................................................. ii

Introduction ........................................................................................................................ 1

Instrumentation ................................................................................................................. 2

Calibration .......................................................................................................................... 2

Analysis ............................................................................................................................... 3

Experimental ...................................................................................................................... 4

Reference materials ...................................................................................................... 4

Field samples................................................................................................................. 4

Treated laboratory soils ............................................................................................... 4

Results and discussion ...................................................................................................... 4

Conclusions ........................................................................................................................ 11

Literature cited ................................................................................................................... 12

Abstract ............................................................................................................................... 15

ILLUSTRATIONS

Figure

1. Spectrum of several characteristic Kα and Kβ peaks for metals and

Compton and Rayleigh backscatter ............................................................... 3

2. Lead concentrations established for spiked soils by both RF/Comp. Kα

normalization and FP analysis ........................................................................ 7

3. Antimony concentrations established for spiked soils by both RF/Comp.

Kα normalization and FP analysis .................................................................. 8

4. Fluorescence yield vs. atomic number for K and L lines ................................. 11

5. Average and standard deviation of concentrations established for

soils spiked with 1000 μg metal/g ................................................................. 12

TABLES

Table

1. Primary sources and analyte lines for metals of environmental concern

that can be detected by X-ray fluorescence spectrometry .......................... 2

2. Daily response factors established for Cu, Zn, As, and Pb based on the

SRM 2710 certified reference material ........................................................... 3

3. List of certified reference materials ..................................................................... 4

4. Characteristics of laboratory-treated soils ......................................................... 4

iii
iv

Table Page

5. Treatment scheme for spiking soil subsamples with metals ........................... 5

6. Detection limit estimates and intensity counts ................................................. 5

7. Analysis of commercial reference materials from the National Institute of

Standards and Technology .............................................................................. 6

8. Analysis of commercial reference materials from Resource Technology

Corporation........................................................................................................ 6

9. Concentrations of Cu, Zn, and Pb determined for field soil samples ............ 7

10. Concentrations of Cr, Cu, Zn, As, and Pb determined for spiked soil

matrices by response factor/Compton Kα peak normalization ................. 8

11. Concentrations of Co, Ni, Hg, Tl, and Se determined for spiked soil

matrices by response factor/Compton Kα peak normalization ................. 9

12. Concentrations of Ag, Cd, Sn, Sb, and Ba determined for spiked soil

matrices by response factor/Compton Kα peak normalization ................. 9

13. Concentrations of Cr, Cu, Zn, As, and Pb determined by fundamental

parameter analysis using the Spectrace 9000 ................................................ 10

14. Concentrations of Co, Ni, Hg, Se, and Fe determined by fundamental

parameter analysis using the Spectrace 9000 ................................................ 10

15. Concentrations of Ag, Cd, Sn, Sb, and Ba determined by fundamental

parameter analysis using the Spectrace 9000 ................................................ 11
INTRODUCTION

Metal pollution over the past decade has come

to be of greater concern due to an increasing awareness of the pathways leading to chronic human

toxicity (Spittler and Fender 1979). During this time

the use of X-ray fluorescence (XRF) analysis has

increased for establishing the presence of elevated

levels of metals in environmental samples (e.g.,

Furst et al. 1985, Piorek and Rhodes 1988, Grupp

et al. 1989, Watson et al. 1989, Ashe et al. 1991,

Carlson and Alexander 1991, Driscoll et al. 1991,

Garby 1991, Harding 1991, Puls et al. 1994, etc.).

This instrumental method of analysis establishes

concentration estimates for several metals over a

concentration range extending from percent levels to around 100 μg/g (ppm). The method requires

little or no sample pretreatment and can be performed for a small fraction of the time and cost

associated with acid extraction/atomic absorption

or emission analysis. Moreover, XRF analysis is

nondestructive, so subsamples can be archived or

analyzed by other procedures. For these reasons,

XRF analysis is a very practical and economical

method when screening for high concentrations

of metals during a remedial investigation and feasibility study (RI/FS) at a suspected hazardous

waste site.

Today several manufacturers offer energy-dispersive XRF spectrometers that have been designed to be compatible with field operations. The

most transportable systems have a battery power

supply option and use one or more radioactive

sources as the primary incident radiation for elemental excitation. The first generation of these

stand-alone systems was equipped with gas

proportional detectors that had a spectral resolution on the order of 800–1000 electron volts (1000

eV = 1 keV). More recently, systems have been

marketed (HNU Systems Inc., Spectrace Instruments, Inc., Metorex, Inc.) with silicon (drifted with

lithium) [Si(Li)] or mercuric iodide (HgI2) detectors capable of achieving resolutions of 170 and

300 eV, respectively. This increased spectral resolution allows for the unambiguous qualitative

identification of metals in complex mixtures.

Quantitatively, however, the measurement of

discrete spectral energies obtained by XRF analysis is often dependent on other metals present in

the sample, due to absorption and enhancement

effects. For environmental sample analysis, these

matrix-specific effects are best addressed by the

use of empirical coefficients (Piorek and Rhodes

1988). This method of instrumental calibration requires the acquisition or development of several

well-characterized materials with a matrix composition similar to that of the samples. Moreover,

the standards should contain a range of metal concentrations bracketing the desired level of

quantitation. Due to these requirements, calibration standards are often both material and site specific, and their preparation and/or verification may

take one or more weeks.

A more practical solution for an initial site investigation would be a calibration method that is

insensitive to sample matrix so that only few standards would be needed to handle a diverse range

of samples (e.g., soil composition “sand/slit/clay,”

sediment, sludge, dust, paint chips, etc.). Ideally,

this capability would allow samples to be analyzed

independent of any previous site characterization.

With this concept in mind, two quantitation routines have been proposed for field-transportable

high-resolution XRF systems. One routine is based

on fundamental parameters (FP) analysis, which

eliminates the need for several calibration standards by relying on certain physical constants to

estimate metal concentration while theoretically

correcting for matrix discrepancies (Figura 1987,

1993). Another approach uses response factors (RF)

Rapid Screening of

Metals Using Portable High-Resolution

X-Ray Fluorescence Spectrometers

ALAN D. HEWITT
rithms based on intensities measured for pure elements, sensitivity coefficients, summations of absorption-enhancement terms in appropriate matrices, and correction factors for overlapping peaks

(Figura 1987). The X-Met 920 FP program also required the analysis of a fully characterized standard material, which for this study was SRM 2710,

from the National Institute of Science and Technology (NIST).

To perform the RF/Comp. Kα normalization

analysis, a standard must be available that contains the analytes of interest in a matrix that is

physically consistent (dry particles) with the

samples. When possible, the RF should be established for well resolved Kα, Kβ, Lα, or Lβ spectral

lines (Table 1). Figure 1 is an example of an XRF

spectrum obtained with the X-Met 920 showing

several characteristic peaks for metals along with

the incoherent (Compton) and coherent (Rayleigh)

sample matrix backscatter.

For this study a finely ground soil, SRM 2710

certified reference soil from NIST, was used to establish the analyte RFs for Cu, Zn, As, and Pb. Table

2 is an example of some of the daily RFs established for these four metals. For the determination

of Cr, the NIST SRM 2711 was spiked with 4000 μg

Table 1. Primary sources and analyte lines for metals

of environmental concern that can be detected by Xray fluorescence spectrometry.

Emission lines (keV)

Source Metals Kα Kβ Lα Lβ

FE-55 Cr† 5.41 5.95

Cd-109 Cr†* 5.41 5.95

Cd-109 Mn† 5.89 6.49

Cd-109 Fe†* 6.40 7.06

Cd-109 Co† 6.92 7.65

Cd-109 Ni† 7.47 8.30

Cd-109 Cu†* 8.04 8.94

Cd-109 Zn†* 8.63 9.61

As†* 10.5 11.8

Cd-109 Se† 11.2 12.6

Hg† 9.98 11.9

Cd-109 Tl 10.3 12.3

Pb†* 10.5 12.6

Am-241 Ag† 22.1 25.2

Am-241 Cd† 23.1 26.4

Am-241 Sn† 25.2 28.8

Am-241 Sb† 26.2 30.1

Am-241 Ba† 32.0 36.8

† Spectrace 9000 preprogrammed for fundamental parameter

analysis of this metal.

* X-Met 920 preprogrammed for fundamental parameter analysis of this metal.

* T.M. Spittler, U.S. Environmental Protection Agency,

Environmental Services Division, Region 1, Lexington,

Massachusetts.

and corrects for matrix discrepancies by normalizing to the Compton Kα (Comp. Kα) incoherent

radiation backscatter peak.*

This study evaluates these two methods of rapid

sample analysis by determining the concentrations

of copper (Cu), zinc (Zn), arsenic (As), lead (Pb),

chromium (Cr), cobalt (Co), nickel (Ni), mercury

(Hg), thallium (Tl), selenium (Se), silver (Ag), antimony (Sb), cadmium (Cd), tin (Sn), and barium

(Ba) in a variety of solid-particle matrices. All

analyses are performed with transportable highresolution XRF systems that can be configured for

stand-alone operations. This combination of rapid

sample analysis and instrumental transportability is well suited for screening purposes, thus a

data quality objective of an accuracy of ±50% and

detection limits of less than 1000 μg/g was used

(Raab et al. 1987).

INSTRUMENTATION

Explanations of the principals of XRF analysis

can be found elsewhere (Driscoll et al. 1991, Hewitt

1994a, b). The instruments used in this study were

the X-Met 920 (Metorex, Inc.; formerly Outokumpu

Electronics) and the Spectrace 9000 (Spectrace Instruments) X-ray spectrophotometers. These two

field-portable systems are equipped with surface

analysis probes allowing for either in situ or intrusive sample analysis and have software-supported

FP analysis capabilities. The Spectrace 9000 is

equipped with three primary radioactive sources,

Fe-55, Cd-109, and Am-241, and has a HgI2 solidstate detector. The X-Met 920 has two radioactive

sources, Cd-109 and Am-241, and has a Si(Li) detector that requires liquid N2 for operation. Table

1 lists some of the metals that can be determined

by these XRF systems. The table also shows those

metals that could be quantitated by FP software

programs supplied by the respective manufacturers.

CALIBRATION

The FP software routines used in this study are

proprietary to the instrument manufacturer. In

general, these FP programs are a series of algo2
5-gram quantities of air-dried

materials with particle sizes averaging <600 μm in diameter. All

samples were placed into 31-mmdiameter cups and covered with

a 0.2-mil polypropylene X-ray

film window. XRF analyses were

performed for a period of 300 seconds. Field operations using these

two preparation steps, i.e., drying

and sieving, have shown that up

to a hundred samples can be processed and analyzed within a

single day (Grupp et al. 1989,

Garby 1991).

Fundamental parameter sample analysis was performed using

both XRF instruments after the selection of the appropriate software application and assessing

the instrumental tuning. For the Spectrace 9000 this

involved checking the resolution and the background response with supplied reference materials and selecting the fine particle application. The

FP software application supplied with the X-Met

920 system was based upon the analysis and total

characterization of the finely ground NIST SRM

2710.

The RF/Comp. Kα normalization analysis method was only performed with the X-Met 920. To perform this method of analysis, the energy spectrum

from each analysis was saved and transformed

from a 2048- to a 256-channel spectrum for close

examination. This approach was used because it

was easier to measure the intensity of smoothed

peaks and, once transformed, up to six spectra

could be overlaid. Measurements included the intensity of elemental spectral lines and the intensity of the incoherent radiation backscatter peak

(Comp. Kα). The intensity of the incoherent radiation backscatter reflects both the composition of

light elements (e.g. carbon, nitrogen, silicon, etc.)

in the sample matrix as well as the overall concentration of detectable analytes (Nielson and Sanders 1983). Intensities of both the baseline and peaks

of interest were recorded from the computer display after selecting the appropriate spectrum channels. Concentration estimates were then manually

determined by multiplying the baseline-corrected

analyte signal intensity by the normalization factor, followed by the response factor. The normalization factor is the quotient of the Compton Kα

peak intensity of the certified reference material,

divided by that of the samples. A more complete

Table 2. Daily response factors established for

Cu, Zn, As, and Pb based on the SRM 2710

certified reference material.

Response factor (intensity/concentration)

Cu Zn As Pb

12.0 33.9 1.09 39.5

11.9 34.8 0.90 38.0

12.3 34.4 1.04 39.6

Average 12.1 34.4 1.01 39.0

Std. dev. 0.21 0.45 0.098 0.90

% RSD 1.7 1.3 9.7 2.3

SRM 2710 concentration (μg/g)

2950 6952 626 5532

Cr/g, to establish an RF. All of the other metals

analyzed were quantified relative to RFs obtained

for the Rocky Mountain Arsenal (RMA) soil matrix spiked with 1000 μg metal/g. Even with a highresolution XRF instrument, the As Kα and Pb Lα

lines (10.532 and 10.549 keV, respectively) overlap, so the As Kβ and Pb Lβ peaks were used. In addition, because high levels (>0.4%) of Fe were present in many of the laboratory-treated soil matrices, the Fe Kβ peak (7.06 keV) had to be subtracted

from the Co Kα peak (6.92 keV), due to a spectral

overlap. In the case of Co, the Kβ line was not used

because of insufficient response (intensity).

ANALYSIS

Only intrusive sample-analysis procedures

were used in this study. Samples consisted of 2- to

Figure 1. Spectrum of several characteristic Kα and Kβ peaks for metals

and Compton and Rayleigh backscatter.

0 50 100 150 200 250

Channel (eV)

Intensity (counts)

Compton Kα

Rayleigh Kα

β Rayleigh K

Compton Kβ

Cr Kα

α Ni K

β Zn K

Cu Kα

Zn Kα

As Kα

Se Kα

As Kβ

Se Kβ

3
description of this analysis has been published

elsewhere (Hewitt 1994a, 1994b).

EXPERIMENTAL

Several reference materials of different solidwaste matrices, along with field-contaminated and

laboratory-treated soils, were analyzed to assess

the performance of both the FP and RF/Comp. Kα

normalization.

Reference materials

Table 3 lists the certified reference materials

purchased from NIST and the Resource Technology Corporation (RTC). Those purchased from

NIST have certified concentrations for the total

amount of metal present, whereas the RTC materials report certified values based on the USEPA

SW846, 3000-series metal acid extraction procedures (U.S. EPA 1986).

Field samples

Six river sediment subsamples from a suspected

hazardous-waste site were analyzed. These field

subsamples were taken from thoroughly homogenized samples that had been previously characterized by inductively coupled plasma (ICP) analysis following 3000-series metal acid extraction procedures (U.S. EPA 1986).

Treated laboratory soils

Six different soils were spiked with Cr, Cu, Zn,

As, Pb, Ni, Se, Hg, Tl, Co, Ag, Cd, Sn, Sb, and Ba

by using concentrated 10,000 mg/L aqueous pure

element atomic absorption standards (AESAR/

Table 3. List of certified reference materials.

National Institute of Standards and Technology

SRM 1645—River sediment

SRM 1646—Estuarine sediment

SRM 1579a—Powdered lead-based paint

SRM 2704—Buffalo River sediment

SRM 2709—San Joaquin soil

SRM 2710—Montana soil

SRM 2711—Montana soil

Resource Technology Corporation

CRM012—Incinerated sludge

CRM014—Baghouse dust

CRM013—Paint chips

CRM020—Soil (from EPA Superfund site)

CRM021—Soil (from contaminated waste site)

Alfa, Johnson Matthey). A complete description

of how these soil subsamples were treated has been

presented elsewhere (Hewitt 1994b). The soil characteristics and the weight of the treated subsamples

are shown in Table 4.

Briefly, the soils were air dried and thoroughly

mixed prior to placing subsamples into 31-mmdiameter analysis cups. Analyte spikes were made

by pipetting between 0.4 and 0.025 mL quantities

of the aqueous standards directly onto the individual soil subsamples, increasing the metal

concentration by 1000, 500, 250, 125, or 0 μg/g.

Only five analytes were applied to a set of five replicate soil subsamples in order to limit the total

volume of solution added to each subsample (0.2

mL/g). Following this protocol, one set of 30 soil

subsamples (5 × 6) was spiked with Cr, Cu, Zn, As,

and Pb, a second with Ni, Se, Hg, Tl, and Co, and

a third with Ag, Cd, Sn, Sb, and Ba. Analyte additions were performed so that a given soil subsample was not treated with the same concentration more than once (Table 5). A sixth untreated

subsample of each soil type was also analyzed with

each group and served as the matrix blank.

RESULTS AND DISCUSSION

Table 6 lists the estimates of detection reported

by the manufacturers for FP analysis, along with

some values established using the RF/Comp. Kα

normalization and method detection limit (MDL)

(Federal Register 1984). This table also includes the

analyte intensities measured for the RMA soil

treated with 1000 μg metal/g. These intensities

were included to provide a means of predicting a

detection limit, based on the assumption that there

is a fairly constant inverse relationship between

these two parameters. This table indicates that regardless of the method of analysis, all of these

Table 4. Characteristics of laboratory-treated soils.

Silt and Grain

Sand clay size* Wt.†

Matrix (%) (%) (μm) (g)

Ottawa sand 100 400 4

Rocky Mountain Arsenal NA NA NA 4

Lebanon landfill 45 55 300 4

CRREL soil NA NA NA 4

Tampa Bay sediments 95 5 200 4

Ft. Edwards clay 30 70 30 2

* 95% cut off

† Weight of soil subsample spiked

NA Not analyzed

4
Pb when the certified concentration was above one

of the estimates of detection listed in Table 6. In

only two cases were the values established by the

RF/Comp. Kα normalization method off by more

than ±50% from the certified values. An apparently

high concentration was established for Cu in the

CRM 021 soil, and a low one for the SRM 2704 river

sediment. Fundamental parameter analysis with

the Spectrace 9000 XRF failed to establish concentrations within ±50% six times, twice each for Cu,

As, and Pb. No values were obtained for Cu in the

SRM 2704 river sediment and SRM 2711 soil, while

low determinations of As occurred for both the

SRM 2710 soil and the CRM 020 soil, and high estimates were obtained for Pb in the CRM 013 paint

chips and the CRM 014 baghouse dust. The FP determinations made with the X-Met 920 failed to

meet this criterion in only three cases. A low value

was established for As in the CRM 020 and high

values for Pb in both the CRM 013 paint chips and

the CRM 014 baghouse dust.

The high values obtained for the CRM reference materials by these two methods of XRF analysis are not necessarily incorrect, since the certified

value is based on an acid extraction that does not

necessarily represent the total amount present.

However, a low determination for these standards,

or one that fails to be within ±50% of the value

stated for the NIST reference materials, would be

aberrant. The low As concentrations determined

by FP analysis had previously been identified as a

problem when samples contain much larger (>10

times) quantities of Pb (Harding 1991). The falsenegative Cu determinations were only for samples

with certified concentrations very close to the estimates of detection. Overall, these two rapid methods of analysis showed that they were fairly insensitive to this wide variety of particulate matrices

by establishing concentrations that would be appropriate for the data quality objectives stated.

Table 9 shows XRF concentration estimates obtained for Cu, Zn, and Pb along with the values

obtained by acid-extraction/ICP analysis. The FP

analysis was only performed with the X-Met 920

XRF analyzer. In those cases where the values obtained by acid-extraction/ICP analysis were above

the appropriate estimate of detection (Table 6), only

Cu in sample A and Zn in sample F had XRF estimates that were off by more than ±50%. A high Cu

value was established by RF/Comp. Kα normalization analysis, and a high Zn value was established by FP analysis. Again, since these reported

estimates were higher than those obtained after

acid extraction and ICP analysis, which is not necTable 5. Treatment scheme for spiking soil

subsamples with metals.

Sets Metal groups

1 Cr Cu Zn As Pb

2 Ni Se Hg Tl Co

3 Sb Ag Ba Cd Sn

Treatment concentrations

Subsample

S1 1000* 125 0 500 250

S2 500 250 1000 0 125

S3 250 0 125 1000 500

S4 125 1000 500 250 0

S5 0 500 250 125 1000

Matrix

blank NF NF NF NF NF

* μg/g

NF Not fortified

Table 6. Detection limit estimates and intensity

counts.

Detection limits (μg/g)

Spectrace X-Met RF/ Peak

Source Metal 9000* 920† Compt.** intensity*†

FE-55 Cr 180 — — —

Cd-109 Cr 525 325 270 1.18

Cd-109 Mn 410 225 — —

Cd-109 Fe 225 200 — —

Cd-109 Co 205 180 — 1.33

Cd-109 Ni 125 175 — 3.82

Cd-109 Cu 90 175 54 6.58

Cd-109 Zn 70 160 90 6.47

Cd-109 As 50 140 42 3.18

Cd-109 Se 35 140 — 18.0

Cd-109 Hg 60 — — 5.33

Cd-109 Tl — — — 7.83

Cd-109 Pb 30 — 48 8.34

Am-241 Ag — 70 — 25.9

Am-241 Cd 180 100 — 24.6

Am-241 Sn 100 80 — 27.1

Am-241 Sb 65 80 — 33.5

Am-241 Ba 20 100 — 31.4

* Minimum detection limit

† Minimum determination limit

** Method detection limit

*

† Matrix-corrected peak intensity for 1000-ppm spiked

RMA soil

metals should be easily quantitated below 1000

μg/g by XRF analysis.

Tables 7 and 8 show the concentration estimates

obtained for the commercial reference materials

by these two methods of rapid sample analysis.

These two tables show results for Cu, Zn, As, and

5
essarily a total concentration, the XRF values may

not be incorrect.

The concentration estimates for Cu, Zn, As, Pb,

Cr, Co, Ni, Hg, Tl, Se, Ag, Cd, Sn, Sb, and Ba in the

laboratory-spiked soil subsamples appear in Tables

10 through 15. Tables 10–12 show the values for

RF/Comp. Kα normalization analysis, and Tables

13–15 show the values for FP analysis using the

Spectrace 9000 XRF analyzer. In addition to these

metals that were spiked onto the soils, values for

iron (Fe) determined by FP analysis are reported

in Table 14. Thallium was not determined by FP

analysis because this metal had not been included

in the software program. All of these concentration estimates were established by using either Cd109 or Am-241 incident radiation (Table 1).

The values in these tables were corrected for

background concentrations present in the soil matrix and for spectral overlap interferences. These

corrections were made when both the subsample

in the treatment set (Table 5) with no spiked analyte

and the subsample of the untreated matrix were

determined to have concentrations that exceeded

the respective estimates of detection listed in Table

6. However, in cases where there was no estimate

of detection for the RF/Comp. Kα normalization

method of analysis, the lowest value appearing in

this table was used. Corrections for Cu, Zn, and

Ba were necessary because these metals were

present at detectable levels in some of the soil

matrices. Corrections were required for Co because

of a spectral overlap with the Kβ peak of Fe and

for Ag due to spectral overlap with a peak characteristic of the Am-241 primary radiation source.

Table 8. Analysis of commercial reference materials

from the Resource Technology Corporation.

Metal concentrations (μg/g)

Standard Cu Zn As Pb

CRM012 3015** 635** 120**

incinerated [2470] [342] [114]

sludge 3590† 744† 126†

3340* 525* 60*

CRM 013 643**

paint chips [460]

2160†

998*

CRM 014 1914**

baghouse dust [2080]

5360t

4925*

CRM 020 soil 753** 3021** 397** 5195**

[687] [4420] [429] [5070]

521† 3550† 113† 4580†

684* 3898* 126* 4950*

CRM 021 soil 5086** 574**

[8720] [549]

3060† 408†

** Certified concentration

[ ] Concentration estimate based on response factor/

Compton Kα peak normalization with X-Met 920 † Concentration estimate based on fundamental parameter analysis with Spectrace 9000

* Concentration estimate based on fundamental parameter analysis with X-Met 920

ND Not detected

Table 7. Analysis of commercial reference materials from

the National Institute of Standards and Technology.

Metal concentrations (μg/g)

Standard Cu Zn As Pb

SRM 1645 109** 1720** 714**

river sediment [72] [1900] [638]

114* 1760* 606*

SRM 1646 138**

estuarine sediment [127]

SRM 1579a 119,950**

lead-based paint [160,000]

144,000†

124,000*

SRM 2704 99** 438** 161**

river sediment [31] [302] [130]

ND† 464† 133†

527* 200*

SRM 2709 soil 106**

[91]

129†

SRM 2710 soil 2950** 6952** 626** 5532**

3350† 7570† 149† 6240†

SRM 2711 soil 114** 350** 105** 1162**

[167] [343] [138] [1100]

ND† 410† ND† 1280†

414* 1210*

** Certified concentration

[ ] Concentration estimate based on response factor/

Compton Kα peak normalization with X-Met 920 † Concentration estimate based on fundamental parameter analysis with Spectrace 9000

* Concentration estimate based on fundamental parameter analysis with X-Met 920

ND Not detected

6
0

0

200

400

600

800

1000

1200

200 400 600 800 1000

Treatment Level (μg/g)

XRF Comp./Kα Normalization Analysis (μg/g)

 Lead


——————————


Ottawa Sand


Ft. Edwards Clay


CRREL Silty/Sand


Rocky Mt. Arsenal


Tampa Bay Sediments


Lebanon Landfill

This study of laboratory-spiked soils was included because commercial reference materials

typically contain only a few metals (e.g., Cu, Zn,

Pb) at concentrations that can be readily detected

by XRF analysis. The soil spiking method used

(Hewitt 1994b) appears to have resulted in fairly

homogenous and accurate analyte concentrations,

as shown by Figures 2 and 3. Plots of the results of

Pb and Sb were chosen to show this feature because XRF analysis is particularly sensitive for

these two metals (Table 6), and they are representative of metals excited by the Cd-109 and Am-241

primary sources, respectively. It is logical to assume that the other metals spiked onto the different soil matrices were likewise evenly distributed.

The results in Tables 10–15 show that these two

methods of rapid sample analysis consistently established concentrations for Cu, Zn, Pb, Se, Ag,

Sn, Sb, and Ba that were within ±50% of the expected values from 1000 to 125 ppm. This was also

the case for Hg as determined by RF/Comp. Kα

normalization analysis. The few aberrant values

for Hg, as established by FP analysis with the

Table 9. Concentrations (μg/g) of Cu, Zn,

and Pb determined for field soil samples.

Metal concentrations (μg/g)

Field samples Cu Zn Pb

A 114** 1140** 253**

[176] [1260] [229]

286* 1500* 318*

B 776** 1390** 488**

[756] [1310] [473]

984* 1810* 614*

C 1860** 261** 2060**

[1750] [182] [1650]

1600* 220* 1600*

D 3960** 735** 546**

[3270] [408] [475]

3510* 688* 494*

E 449** 1260** 350**

[443] [1230] [328]

567* 1710* 416*

F 104** 182** 87**

[145] [200] [108]

331* 391* 245*

** Concentrations based on acid-extraction/

ICP analysis

[ ] Concentration estimate based on response

factor/Compton Kα peak normalization

with X-Met 920

* Concentration estimate based on fundamental parameter analysis with X-Met 920

Spectrace 9000, were most likely caused by a peak

overlap with Tl. This problem occurred because

Tl had not been one of the metals included in the

FP software. With the exception of a few values

established for the two lowest treatment levels for

As and Cd (and Tl by RF/Comp. Kα) these metals

were also within the ±50% concentration criterion.

Clearly, the concentrations of all of these metals

can be adequately estimated at 1000 μg/g and below by these two rapid methods of XRF analysis.

Furthermore, since both methods established concentration trends that were consistent with the

treatment levels, they would correctly define the

areas of greatest concern.

Figure 2. Lead concentrations (μg/g) established

for spiked soils by both RF/Comp. Kα normalization and FP analysis. XRF—RF/Comp. Kα Normalization Analysis (μg/g)

1200

800

400

Treatment Level (μg/g)

XRF—Fundamental Parameter Analysis (μ g/g)

0 400 800 1200

Ottawa Sand

Ft. Edwards Clay

CRREL Silty/Sand

Rocky Mt. Arsenal

Tampa Bay Sediments

Lebanon Landfill

Lead

XRF—Fundamental Parameter Analysis (μg/g)

7
Table 10. Concentrations (μg/g) of Cr, Cu, Zn, As, and Pb

determined for spiked soil matrices by response factor/

Compton Kα peak normalization.

Metal concentrations (μg/g)

Material & spike Cu Zn As Pb Cr

Ottawa sand

1000 ppm 1010* 1020 1420 911 1770

500 ppm 534* 458 381 411 856

250 ppm 264* 224 324 182 312

125 ppm 132* 127 72 139 84

0 ppm 69 ND ND ND ND

Matrix 64 18 ND 10 ND

Ft. Edwards clay

1000 ppm 711* 751* 906 785 979

500 ppm 289* 374* 491 344 638

250 ppm 144* 252* 229 150 175

125 ppm 142* 91* 104 108 304

0 ppm 199 81 ND 19 46

Matrix 218 80 ND 4 ND

CRREL soil

1000 ppm 787* 870 782 1030 1100

500 ppm 461* 541 635 597 439

250 ppm 250* 247 320 178 220

125 ppm 69* 152 26 130 250

0 ppm 86 48 48 ND 93

Matrix 62 59 ND 18 257

Rocky Mountain Arsenal

1000 ppm 897* 1050 1450 960 1160

500 ppm 483* 459 608 470 493

250 ppm 209* 245 304 211 349

125 ppm 93* 153 105 125 229

0 ppm 76 ND 37 ND 205

Matrix 62 2 41 23 ND

Tampa Bay sediments

1000 ppm 842* 939 1350* 936 1570

500 ppm 513* 486 560* 526 653

250 ppm 250* 218 200* 219 639

125 ppm 103* 159 73* 124 219

0 ppm 60 11 220 7 120

Matrix 71 ND 249 ND 99

Lebanon landfill soil

1000 ppm 859* 872 988 1192 1500

500 ppm 373* 469 536 423 495

250 ppm 195* 224 305 264 407

125 ppm 94* 140 78 135 326

0 ppm 99 2 ND ND ND

Matrix 70 8 ND 24 ND

* Average of 0 ppm and matrix subsamples subtracted

ods of analysis tended to establish high estimates

for Cr for soil matrices with low Fe content. Even

though this apparent matrix effect was not adequately handled by either of these two methods

of analysis to meet the ±50% criterion consistently,

the appropriate concentration trends were established.

The remaining metals in this study, Ni, Co,

and Cr, required additional qualifications because their estimates of detection precluded

some of the lower laboratory treatment levels.

For instance, Ni and Co could only be assessed

for spiked concentrations that were >205 ppm

(μg/g), likewise Cr for concentrations >525 ppm

and >270 ppm for FP and the RF/Comp. Kα

analysis, respectively. Values for all three of

these metals were established by both methods of

analysis that failed to meet the ±50% concentration criterion. High concentration estimates tended

to be established for both Ni and Co by FP analysis in soils with low Fe content (Table 14). In contrast, low concentrations of these two metals were

established by RF/Comp. Kα normalization analysis when high levels of Fe were present. Both methFigure 3. Antimony concentrations (μg/g) established for spiked soils by both RF/Comp. Kα normalization and FP analysis.

0 400 800 1200

Treatment Level (μg/g)

1200

800

400

α XRF-RF/Comp. K Normalization Analysis ( μg/g)

Ottawa Sand

Ft. Edwards Clay

CRREL Silty/Sand

Rocky Mt. Arsenal

Tampa Bay Sediments

Lebanon Land Fill

Antimony

0 400 800 1200

Treatment Level (μg/g)

1200

800

400

XRF-Fundamental Parameter Analysis (μ g/g)

Ottawa Sand

Ft. Edwards Clay

CRREL Silty/Sand

Rocky Mt. Arsenal

Tampa Bay Sediments

Lebanon Land Fill

Antimony

XRF—RF/Comp. Kα Normalization Analysis (μg/g) XRF—Fundamental Parameter Analysis (μg/g)

Landfill

Landfill

8
Several factors that control the sensitivity of elemental analysis by XRF analysis are independent

of matrix composition. First of all, elements with

low atomic numbers have low fluorescence yields

(Fig. 4). The fluorescence yield is the ratio of number of vacancies created within an atom by the incident radiation to the number of vacancies that

actually result in the production of characteristic

X-ray photons (Jenkins 1986). In addition, since

only a few isotopes are available for field-portable

XRF systems, there can be a large separation between incident and excitation energies. The greater

this separation, the lower the analyte response, because fewer atoms become excited. A third factor

Table 11. Concentrations (μg/g) of Co, Ni, Hg, Tl, and Se

determined for spiked soil matrices by response factor/

Compton Kα peak normalization.

Metal concentrations (μg/g)

Material & spike Co Ni Hg Tl Se

Ottawa sand

1000 ppm 1250 1230 758 909 977

500 ppm 539 609 471 532 502

250 ppm 267 290 149 421 231

125 ppm 199 90 132 225 89

0 ppm ND ND 13 52 ND

Matrix ND ND ND 13 ND

Ft. Edwards clay

1000 ppm 200* 496 623 813 675

500 ppm 50* 260 268 482 449

250 ppm ND* 187 145 347 136

125 ppm ND* 90 120 199 73

0 ppm 6500 45 ND 63 ND

Matrix 6300 16 ND ND ND

CRREL soil

1000 ppm 390* 761 823 993 882

500 ppm ND* 356 323 553 519

250 ppm 180* 93 141 330 238

125 ppm ND* 15 110 225 128

0 ppm 4050 ND 43 66 8

Matrix 4070 ND ND ND ND

Rocky Mountain Arsenal

1000 ppm 560* 947 933 1030 977

500 ppm 270* 481 395 545 483

250 ppm 60* 298 179 449 211

125 ppm 50* 86 161 216 111

0 ppm 1580 12 21 33 ND

Matrix 1680 ND ND 12 ND

Tampa Bay sediments

1000 ppm 846* 962 933 997 1010

500 ppm 482* 457 395 519 460

250 ppm 178* 315 179 425 221

125 ppm 103* 129 161 199 124

0 ppm 193 22 21 73 ND

Matrix 135 ND ND 7 11

Lebanon landfill soil

1000 ppm 435* 838 550 996 968

500 ppm 395* 470 472 460 511

250 ppm 135* 179 207 435 192

125 ppm 85* 88 148 253 123

0 ppm 2260 ND 21 45 ND

Matrix 2170 ND ND 14 ND

* Average of 0 ppm and matrix subsamples subtracted

Table 12. Concentrations (μg/g) of Ag, Cd, Sn, Sb, and

Ba determined for spiked soil matrices by response factor/Compton Kα peak normalization.

Metal concentrations (μg/g)

Material & spike Ag Cd Sn Sb Ba

Ottawa sand

1000 ppm 1170 1000 986 1060 1160

500 ppm 646 499 398 557 527

250 ppm 269 176 226 302 262

125 ppm 109 48 145 160 121

0 ppm 19 ND 97 ND ND

Matrix 25 ND 25 12 ND

Ft. Edwards clay

1000 ppm 1032* 936 899 1080 996*

500 ppm 604* 334 447 495 496*

250 ppm 297* 162 248 317 288*

125 ppm 166* 42 146 152 163*

0 ppm 312 ND 92 ND 703

Matrix 263 ND 26 20 665

CRREL soil

1000 ppm 896* 1040 918 996 1030*

500 ppm 363* 531 459 493 489*

250 ppm 179* 253 286 295 273*

125 ppm 82* 153 142 142 118*

0 ppm 169 ND 81 ND 392

Matrix 159 ND 36 14 410

Rocky Mountain Arsenal

1000 ppm 992* 984 745 1070 1060*

500 ppm 410* 416 418 538 530*

250 ppm 297* 142 246 274 220*

125 ppm 140* 42 155 143 130*

0 ppm 246 ND 95 ND 914

Matrix 230 ND 37 11 967

Tampa Bay sediments

1000 ppm 1210* 1060 899 1080 1050

500 ppm 567* 488 447 495 596

250 ppm 368* 203 348 317 287

125 ppm 153* 94 146 152 152

0 ppm 167 ND 92 ND 28

Matrix 160 ND 26 20 29

Lebanon landfill soil

1000 ppm 1040 1070 902 1060 990*

500 ppm 535 436 454 496 498*

250 ppm 314 297 248 304 247*

125 ppm 180 182 150 144 118*

0 ppm 49 36 90 ND 360

Matrix 55 72 31 15 439

* Average of 0 ppm and matrix subsamples subtracted

9
is the depth of penetration achieved by the incident radiation, i.e., how much of the sample is actually analyzed. The penetration depth of incident

radiation is inversely proportional to its wavelength and directly proportional to its energy. For

the sources used in this study, the depth of penetration (99% attenuation) for a quartz matrix

ranges from 40 mm for Am-241 to 4.8 mm for Cd109. The combination of these factors controls the

intensity that will be measured for a given element.

For example, Table 6 shows the range of analyte

intensities obtained for the same concentration in

the RMA soil.

To illustrate the combination of these two efTable 13. Concentrations (μg/g) of Cr, Cu, Zn, As, and

Pb determined by fundamental parameter analysis

using the Spectrace 9000.

Metal concentrations (μg/g)

Material & spike Cu Zn As Pb Cr

Ottawa sand

1000 ppm 1430 1320 1380 976 3010

500 ppm 731 652 389 531 1120

250 ppm 270 287 335 274 580

125 ppm 102 152 51 131 310

0 ppm ND ND ND ND ND

Matrix ND ND 10 ND ND

Ft. Edwards clay

1000 ppm 1340 1140* 1020 1020 850

500 ppm 532 524* 660 467 300

250 ppm 334 192* 343 225 ND

125 ppm 227 147* 13 138 ND

0 ppm 131 99 ND ND ND

Matrix 67 99 66 ND ND

CRREL soil

1000 ppm 1130 1270* 1280 1040 940

500 ppm 489 550* 656 657 57

250 ppm 253 221* 311 232 53

125 ppm 77 120* 60 172 ND

0 ppm ND 74 ND ND ND

Matrix ND 95 56 ND ND

Rocky Mountain Arsenal

1000 ppm 1280 1240 1350 1170 1480

500 ppm 678 675 636 589 440

250 ppm 236 333 375 281 280

125 ppm 74 125 19 141 120

0 ppm ND ND 22 ND ND

Matrix ND 36 28 ND ND

Tampa Bay sediments

1000 ppm 1210 1250 1230 1100 1490

500 ppm 662 545 651 477 700

250 ppm 312 289 278 256 120

125 ppm 70 118 63 83 ND

0 ppm ND ND 12 ND 66

Matrix ND ND 23 ND ND

Lebanon landfill soil

1000 ppm 1130 1130 1110 1130 1350

500 ppm 584 613 567 460 450

250 ppm 316 327 332 218 150

125 ppm 71 133 59 130 ND

0 ppm ND 13 11 ND ND

Matrix ND 22 43 ND ND

* Average of 0 ppm and matrix subsamples subtracted

Table 14. Concentrations (μg/g) of Co, Ni, Hg, Se, and Fe

determined by fundamental parameter analysis using

the Spectrace 9000.

Metal concentrations (μg/g)

Material & spike Co Ni Hg Se Fe

Ottawa sand

1000 ppm 1830 1538 1010 1240 ND

500 ppm 994 846 781 637 79

250 ppm 442 427 228 307 67

125 ppm 109 183 380 143 120

0 ppm ND ND 111 ND 118

Matrix ND ND ND ND 1420

Ft. Edwards clay

1000 ppm 727* 999 791 1100 55,400

500 ppm 277* 495 458 503 54,600

250 ppm 67* 207 200 265 56,700

125 ppm ND* 12 360 120 57,000

0 ppm 560 ND 80 ND 55,600

Matrix 406 ND ND ND 56,900

CRREL soil

1000 ppm 965* 1210 1321 1350 40,000

500 ppm 295* 624 665 611 40,900

250 ppm 235* 216 259 332 41,100

125 ppm 315* 148 155 146 41,100

0 ppm 190 11 95 ND 41,300

Matrix 280 ND 16 ND 40,900

Rocky Mountain Arsenal

1000 ppm 1490 1480 1170 1390 18,600

500 ppm 900 786 736 689 19,600

250 ppm 479 324 301 304 22,500

125 ppm 224 141 579 140 21,700

0 ppm ND ND 121 ND 21,100

Matrix ND ND ND ND 20,100

Tampa Bay sediments

1000 ppm 1710 1720 1350 1310 4410

500 ppm 738 687 728 758 4240

250 ppm 423 308 356 350 3930

125 ppm 198 152 529 185 3470

0 ppm 122 32 151 ND 3500

Matrix 24 ND ND ND 4190

Lebanon landfill soil

1000 ppm 1330 1280 1040 1260 24,900

500 ppm 660 578 744 705 25,900

250 ppm 208 294 227 346 25,500

125 ppm 160 119 336 134 27,200

0 ppm ND ND 151 ND 25,600

Matrix 109 14 ND ND 25,700

* Average of 0 ppm and matrix subsamples subtracted

10
Table 15. Concentrations (μg/g) of Ag, Cd, Sn, Sb, and Ba

determined by fundamental parameter analysis using the

Spectrace 9000.

Metal concentrations (μg/g)

Material & spike Ag Cd Sn Sb Ba

Ottawa sand

1000 ppm 937 1110 1000 915 772

500 ppm 504 581 429 474 353

250 ppm 274 394 269 196 174

125 ppm 193 229 174 109 75

0 ppm 77 111 43 ND ND

Matrix 25 74 41 ND ND

Ft. Edwards clay

1000 ppm 820 976 857 654 601*

500 ppm 377 542 452 345 300*

250 ppm 197 361 226 261 215*

125 ppm 86 172 154 108 148*

0 ppm ND 127 74 ND 379

Matrix ND 100 81 17 436

CRREL soil

1000 ppm 998 1060 1050 955 715*

500 ppm 508 584 527 490 381*

250 ppm 268 302 301 276 201*

125 ppm 191 225 153 122 92*

0 ppm 67 51 37 16 288

Matrix 40 99 28 ND 329

Rocky Mountain Arsenal

1000 ppm 1060 1200 1040 1010 850*

500 ppm 535 613 486 562 472*

250 ppm 296 406 336 221 250*

125 ppm 190 253 194 133 105*

0 ppm 77 143 33 22 716

Matrix 37 80 58 14 734

Tampa Bay sediments

1000 ppm 989 1141 1030 897 706

500 ppm 486 557 485 445 365

250 ppm 268 299 205 235 215

125 ppm 181 189 114 115 92

0 ppm 56 42 51 ND ND

Matrix 56 84 55 12 ND

Lebanon landfill soil

1000 ppm 914 1190 1020 930 832*

500 ppm 525 608 538 515 343*

250 ppm 301 337 287 259 232*

125 ppm 205 223 165 133 111*

0 ppm 39 66 41 ND 278

Matrix ND 18 71 18 300

* Average of 0 ppm and matrix subsamples subtracted

fects, matrix composition and characteristic analyte

response, Figure 5 shows the average concentration and standard deviations for the 1000 μg metal/

g spiked soil matrices. Overall, both the precision

and accuracy of analysis improves with atomic

number. However, for Cr, Co, and Ni, the degree

of bias and range of uncertainty shows that values

even at this level can be greater than ±50% from

the true concentration when analyzing a variety of soils. Most likely, the bias in the determined concentrations is the result of a matrix

effect, while the extent of uncertainty is a function of both the matrix effect and the characteristic analyte response.

In summary, these two methods of rapid sample

analysis with field-portable XRF systems often

achieved the data requirement for screening of

±50% accuracy at and below a concentration of

1000 μg/g. This goal was accomplished for a

variety of soil matrices, and the results in Tables

7–9 show that this approach is also promising

for several other particulate matrices (e.g., sediment, dust, paint chips, and sludge). The determination of Ni, Co, and Cr, however, was not

found to accomplish this goal consistently, even

though reported estimates of detection for XRF

analysis are well below 1000 μg/g. It appears

that for analytes with poor XRF sensitivity, matrix effects are more problematic, and matrixspecific standards would be necessary to

achieve a ±50% accuracy.

CONCLUSIONS

With the exception of Ni, Co, and Cr, the determination of Cu, Zn, As, Pb, Hg, Tl, Se, Ag, Cd, Sn,

Sb, and Ba at and below 1000 μg/g in a variety of

solid particulate materials was often within ±50%

of the expected values when using either funda1.0

0.8

0.6

0.4

0.2

0 20 40 60 80 100

Atomic Number

Fluorescence Yield

K

L

Figure 4. Fluorescence yield vs. atomic number for

K and L lines.

11
2400

2000

1600

1200

800

400

0

Cr Co Ni Cu Zn As Se Hg Tl Pb Ag Cd Sn Sb Ba

Element

Concentration (μg/g)

50

%

– 

50%

Fundamental Parameter

RF/Comp. K Normalization α

mental parameter or response factor/Compton Kα

peak-normalization methods of analysis. These alternative approaches to XRF analysis are very useful for screening a variety of matrices during RI/

FS activities when it is impractical to produce matrix-matched standards.

LITERATURE CITED

Ashe, J.B., P.F. Berry, G.R. Voots, M. Bernick and

G. Prince (1991) A high resolution portable XRF

HgI2 spectrometer for field screening of hazardous waste. In Proceedings of the 2nd International

Symposium on Field Screening for Hazardous Waste

and Toxic Chemicals, February 12–14, Las Vegas, Nevada, p. 507–514.

Carlson, C.D. and J.R. Alexander (1991) Data quality assurance/quality control for field X-ray fluorescence spectrometry. In Proceedings of the 2nd

International Symposium on Field Screening for Hazardous Waste and Toxic Chemicals, February 12–14,

Las Vegas, Nevada, p. 525–532.

Driscoll, J.N., J.K. Marshall, C. Wood and T.

Spittler (1991) A multifunctional portable X-ray

fluorescence instrument. American Laboratory, July,

p. 25–36.

Federal Register (1984) Definition and procedure

for the determination of the method detection limit.

Code of Federal Regulations, Part 136, Appendix

B, October 26.

Figura, P.M. (1993) Standardless X-ray fluorescence analysis of liquids. American Laboratory, July,

p. 40–43.

Figura, P.M. (1987) Standardless quantitative Xray fluorescence analysis using stored calibration

constants. American Laboratory, February, 19(2):

156–164.

Furst, G.A., V. Tillinghast and T.M. Spittler (1985)

Screening for metals at hazardous waste sites: A

rapid cost-effective technique using X-ray fluorescence. In Proceedings of the National Conference on

Management of Uncontrolled Hazardous Waste Sites,

Washington, D.C.,

Garby, J.C. (1991) Comparison of mobile laboratory XRF and CLP split sample lead results from a

Superfund site remediation in New Jersey. In Proceedings of the 2nd International Symposium on Field

Screening for Hazardous Waste and Toxic Chemicals,

February 12–14, Las Vegas, Nevada, p. 671–672.

Grupp, D.J., D.A. Everitt, R.J. Bath, and R. Spear

(1989) Use of a transportable XRF spectrometer for

on-site analysis of Hg in soils. American Laboratory,

November, p. 32–40.

Harding, A.R. (1991) Low concentration soil contaminant characterization using EDXRF analysis.

In Proceedings of the 2nd International Symposium on

Field Screening for Hazardous Waste and Toxic Chemicals, February 12–14, Las Vegas, Nevada, p. 517–523.

Hewitt, A.D. (1994a) Screening for metals by Xray fluorescence spectrometry/response factor/

Compton Kα peak normalization analysis. American Environmental Laboratory, June, p. 24–26.

Hewitt, A.D. (1994b) Screening for metals by Xray fluorescence spectrometry using a single calibration standard. USA Cold Regions Research and

Engineering Laboratory, Special Report 94-20.

Jenkins, R. (1984) X-ray fluorescence analysis.

Analytical Chemistry, 56(9): 1099A–1103A

Nielson, K.K., and R.W. Sanders (1983) MultiFigure 5. Average and standard deviation

of concentrations established for soils spiked

with 1000 μg metal/g, as determined by RF/

Comp. Kα normalization and FP analysis.

50%

–50%

12
waste screening. Environmental Monitoring Systems Laboratory, Las Vegas, Nevada, EPA/600/4-

87/021, National Technical Information Service,

PB87-227633.

Spittler, T.M. and W.A. Fender (1979) A study of

soil contamination and plant lead uptake in Boston urban gardens. Communications in Soil Science

and Plant Analysis, 10(9): 1195–1210.

U.S. EPA (1986) Test Methods for Evaluating Solid

Waste, Vol. 1B. Washington, D.C.: Environmental

Protection Agency.

Watson, W., J.P. Walsh and B. Glynn (1989) Onsite X-ray fluorescence spectrometry mapping of

metal contaminants in soils at Superfund sites.

American Laboratory, July.

element analysis of unweighed biological and geological samples using backscatter and fundamental parameters. Advances in X-Ray Analysis 1983,

26:385–390.

Piorek, S. and J.R. Rhodes (1988) A new calibration technique for X-ray analyzers used in hazardous waste screening. In Proceedings of the 5th National Conference on Hazardous Waste and Hazardous

Materials, April 19–21, Las Vegas, Nevada, p. 428–433.

Puls, R., D.A. Clark, C. Carlson and J. Vardy (1994)

Characterization of chromium-contaminated soils

using field-portable X-ray fluorescence. Ground

Water Monitoring and Remediation, 14: 111–115.

Raab, G.A., D. Cardenas, S.J. Simon and L.A.

Eccles (1987) Evaluation of a prototype field-portable X-ray fluorescence system for hazardous

13
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April 1995

Rapid Screening of Metals Using Portable High-Resolution X-Ray

Fluorescence Spectrometers

Alan D. Hewitt

U.S. Army Cold Regions Research and Engineering Laboratory

72 Lyme Road Special Report 95-14

Hanover, New Hampshire 03755-1290

U.S. Army Environmental Center

Aberdeen Proving Ground, Maryland 21010-5401 SFIM-AEC-ET-CR-95039

Approved for public release; distribution is unlimited.

Available from NTIS, Springfield, Virginia 22161

21

Analysis Field analysis Soil analysis X-ray spectrometry

UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED UL

Analysis of copper, zinc, arsenic, lead, chromium, cobalt, nickel, mercury, thallium, selenium, silver, antimony,

cadmium, tin, and barium was performed on soils and other particle matrices using two field-portable highresolution X-ray fluorescence spectrometers (XRF). Quantitative determinations were based on fundamental

parameter analysis and a second method that relies on analyte response factors and uses the Compton Kα

incoherent backscatter peak for matrix normalization. These two methods of instrumental analysis require only

a few reference materials and are relatively insensitive to sample matrix composition. This study assessed the

capability of these two rapid XRF analysis methods by determining metal concentrations in reference materials,

field samples, and laboratory spiked soils. With the exception of nickel, cobalt, and chromium, concentrations

within 50% of the expected values were consistently obtained at and below 1000 μg/g.