mikron 81
leitfähigkeitsmeßgerät

mikron 81 conductivity meter
Operations manual2© 2018
Wissenschaftliche Gerätebau „F. F. Runge“ GmbH(“F. F. Runge” Scientific Instruments)
David-Gilly-Straße 114469 Potsdam
Germany
Telephone +49 (0) 3 31 / 96 79 75 00
Telefax+49 (0) 3 31 / 96 79 75 02

E-Mailinfo@ff-runge.deInternet

www.ff-runge.deWe reserve the right to make changes
Reprints – even for excerpts – not permitted
Runge is a registered trademark of Wissenschaftliche Gerätebau „F. F. Runge“ GmbH.
Any other marks and protected trademarks named in the following are the property of their respective owners.
Printed in Germany

81.6A0.1807.en

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Table of contents
Introduction............................................................................................................................................................ 5
Safety regulations............................................................................................................................................... 6Intended use...................................................................................................................................... 6
Occupational safety......................................................................................................................... 7
Ambient conditions........................................................................................................................... 7
An overview of the detector........................................................................................................................... 8
Technical data....................................................................................................................................................... 9
Method of measurement.............................................................................................................................. 10Equipment delivered...................................................................................................................... 11
Setting up............................................................................................................................................................. 12Mounting, fastening....................................................................................................................... 12
Liquid connectors.......................................................................................................................... 14
Electrical connection..................................................................................................................... 15en

4Operation.............................................................................................................................................................. 16
Switching on and off...................................................................................................................... 16
Display of the operating status.................................................................................................... 16
Choice of data rate and time constant...................................................................................... 17
Measurement by temperature equalisation............................................................................... 18
Determining the specific temperature coefficient for the material........................................19
Rinsing, cleaning and storing the measurement cell...............................................................19
Replacing the measurement cell................................................................................................. 20
Trouble shooting............................................................................................................................................... 23
Annexe 1: Spare parts list............................................................................................................................ 25
Annexe 2: GLP detector specifications.................................................................................................. 27Conformity declaration.................................................................................................................................. 29

5Introduction
Thank you for deciding for a Runge detector.
Our mikron apparatus differs both in its concept and size from traditional detectors: it gives
you the the performance of advanced laboratory detectors in the form of a test head. This
gives you new application possibilities. Important aims in its development were durability,ease of maintenance and a good price/performance ratio.
We develop and produce all Runge instruments in Germany. We rely on competentsuppliers in Brandenburg and in Berlin. We hope that you will be satisfied with our detectorin its day to day usage and that we can gain your long-term custom.

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Safety regulations
This detector meets the prescribed safety regulations. Incorrect operation can however leadto injury and damage. Consequently read these operating instructions carefully before putting the detector into operation.
Runge cannot accept responsibility for damage caused by not following these instructions.
Intended use
This detector is to be used in analytical and preparative liquid chromatography equipment
and in general for the photometric analysis of liquids. The insertion and operation of thedetector shall only be carried out by trained laboratory technicians with knowledge in thisfield and experience in handling the chemicals used.

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Occupational safety
When using the apparatus observe the health and safety regulations (among others thoseconcerning protective clothing and laboratory equipment). In the United Kingdom, relevant
information is provided by the Health and Safety Executive. In Ireland it is the Health andSafety authority, in Australia, Safe Work Australia and in New Zealand, Worksafe. In theUnited States of America it is the OSHA, in Canada the CSC.
Ambient conditionsThe detector is to be operated only in the following conditions:• Temperature 3...45 °C (37.4...113 °F)• Humidity 0...90 %, non-condensing• Atmosphere: air in room, inert gas, no explosive or corrosive fumes• No direct sunlight (danger of overheating)• No ignition sources in the vicinity of flammable solventsen8An overview of the detector

33461

25331 measurement cell (various types can be supplied)
2 detector block
3 liquid joint

Fig. 1: The mikron 81 detector

4 status indicator
5 electrical connection (USB-C), max. 500 mA
6 name plate9Technical dataTypemikron 81, conductivity meter

Construction typeportable–6–1–5

Conductivity measuring range

S/cm 10 ...10 ; 10 ...1

depending on measuring cell constantConductivity accuracy%+/– 2through three point calibration

Conductivity scanning rate

Hz

10

Temperature measuring range°C

0 … 100

Temperature accuracy°C±0,1

Temperature scanning rate

Hz10Power take-upW< 2,5en10Method of measurement
The concentration, valence and mobility of the ions dissolved in the liquid indicates itscomposition, for example the salt content. The electric conductivity of the liquid is
proportional to the aforementioned ion properties, with their mobility depending on thetemperature of the liquid. The conductivity is measured with a high degree of accuracy byapplying an AC voltage to a cuvette (either filled with the liquid or subjected to a flow of theliquid) of known measurements (cross-sectional area, separation of the electrodes) via thezero voltage point (UW = 0) of a Wien bridge.
2132Zcell
3AlUq~2R1Z3UWV

σ = Gcell

R2Uq~
Zcell

l[σ] = S/mA

1 measuring cell
2 electrode3 sample
A cross-section
l distanceG conductance
Z impedanceUq~ source voltage
UW Wien voltage

Fig. 2: Using a Wien measurement bridge for measuring electrical conductivity

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By using alternating current, polarisation of the investigated liquid during time-consuming
measurements is avoided. The influence of the liquid’s temperature is compensated for. By
using a number of measurement cells differing from each other, each with its own geometry,the measurement range of the detector can be adapted for the measurement task in eachcase. The materials moistened by the liquid (PEEK for the body of the cell, titanium for theelectrodes, PTFE for the seals) are biologically compatible.
Equipment delivered• Runge mikron 81 conductivity meter• connecting cable for USB-C to USB-A, 1.5 m• operating instructions• two pairs of liquid screw joints of the appropriate size
• size 3 Allen key• table mounting1• instrument case1

1

only in the delivered equipment for end users

en12Setting up
Mounting, fastening
With the table mounting delivered, the mikron 81 detector can be operated in a laboratory,
but can also be inserted into a device insofar as the ambient conditions (temperature,humidity, composition of the atmosphere) are maintained.
When inserting the apparatus into a device, fastening it at the front of the detector block isrecommended (see Fig. 4), as this would not constrict the cross-section and otherwise thehousing would be deformed. A suitable means of fastening is, for example, pipe clips
conforming to DIN 3015.
As liquid only flows through the measurement cell, a leak can occur in the cell. To avoid
damage to electronic parts of the detector through the presence of liquid, it is recommended when inserting the measurement cell vertically or at an angle to ensure that its end
cap is located at the deepest point. In the case of horizontal insertion the longitudinalalignment groove should be situated at the bottom along with the overflow outlet of the13

measurement cell (Fig. 6). As leakages are not recognised by the detector, care must be
taken that leakages are discovered in time.

enFig. 3: Table mounting

Fig. 4: Preferred position for fastening clip
1 outlet overflow
2 alignment groove
21Fig. 5: Measurement cell at the bottom

Fig. 6: Alignment groove at the bottom

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Liquid connectors
The mikron 81 detector can be fitted with various measurement cells. These cells use thefollowing joints:
Part number

Measurement cell

OD Capillary tube (mm)Joint

81.240.000x

analytic 5 µl

1.5875 (1/16 inch)

1/4“-28 UNF

flat

81.240.001x

preparative 20 µl

3.1750 (1/8 inch)

1/4“-28 UNF

flat

Two pairs of appropriate joints are supplied with the apparatus. The order of the joints isshown in Fig. 7.
Only PEEK joints should be used with this detector. They must be tightened with a torqueof 0.5 Nm. Joints of PEEK (polyether ether ketone) are not suitable for all operatingpressures and solvents.

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1/16”
knurled-head screw PEEK 1/4”-28 UNF

ferrule1/8”
ferruleknurled-head screw PEEK 1/4”-28 UNF

Fig. 7: Liquid joints, alignment of the partsenElectrical connection
The mikron 81 is connected to a computer via a USB connector and is controlled andsupplied with energy via the connector. The USB-C type plug is constructed symmetricallyand hence can be plugged in in two directions.

16Operation
Switching on and off
The detector is supplied via the USB connector with power and is switched on as soon as
the supply voltage is applied, i.e. as soon as the connected computer or active USB hub isswitched on. The light source(s) are switched on and off via a separate command.
Display of the operating status
The mikron 81 detector can only be remotely controlled via a computer. The apparatus has a
3-coloured status display. This can show the following three operating states:
ColourType

Meaninggreen

steady light

operational

green

flashing lightmeasurement in process

17ColourType

Meaningyellow

steady lightstartup test in processredsteady lighterror

Choice of data rate and time constant
Data rate and time constants concern the processing of the measured signal in the detector
before outputting to the computer. The data rate determines the quantity of data points per
second on the time axis of the chromatogram, and the time constant defines thecommunication of the signal within the chosen time interval. The longer the interval, thelower the noise level, and the time-based resolution is also lower. This should be kept inmind when choosing the constant.
A data rate is recommended which is more than double the reverse value of the time
constant, so that at least two data points are located in an interval of the time constant. At
the same time the data rate should be so chosen that the narrowest expected peak in thechromatogram is defined with at least 20 data points.

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In the case of an unknown duration of the signal peaks it is recommended to make achromatogram with time constant τ = 0 ms or τ = 10 ms and to choose a time constantshorter than half of the narrowest amplitude.
Measurement by temperature equalisation
The temperature of a solution has an influence on its electrical conductivity. Thisdependency is linear for most materials, as shown in Fig. 8, equation 1. For a few materials
e.g. natural water, a non-linear function in accordance with DIN 7888 is applicable. The
mikron 81 is fitted with a linear temperature equalisation device. Furthermore, the specifictemperature coefficient (in %/°C) of the material investigated, which can be looked up inchemical tables, will be added to the chromatography programme.
σ(ϑ) = σ(ϑref )cϑ=100 + cϑ(ϑ – ϑref )100(σ(ϑ2 ) – σ(ϑref )) · 100(ϑ2 – ϑref ) · σ(ϑref )

(1)
(2)

σ
ϑ
cϑ
ref

electrical conductivity
temperature
specific temperature coefficientreference

Fig. 8: Linear temperature dependence of electrical conductivity

S/m°C%/°C

19Determining the specific temperature coefficient for the material
If the electrical conductivity of the material to be investigated is known for a particulartemperature (reference temperature) but the temperature coefficient is not known, the lattercan be calculated by measuring the conductivity at another temperature using equation 2 ofFig. 8. In this case, the temperature equalisation function of the mikron 81 must be switched
off. The measurement temperature should be at least 10 °C higher than the referencetemperature.
Rinsing, cleaning and storing the measurement cell
The cleanliness of the measurement cell is critical for the accuracy and reproducibility of themeasuring result. It is recommended to rinse out the measurement cell with distilled water
between measurements.
When cleaning a significantly soiled cell a cleaning solution is recommended which consists
in equal parts of isopropyl alcohol and a 32% solution of hydrochloric acid. The cell is filled

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with this solution, exposed to it for two or three minutes and then rinsed out thoroughly
several times with distilled water.
When storing the measurement cell for some time without use (longer than two weeks) thecell is first of all rinsed or cleaned and residual liquid is then forced out from the cell’sinterior using compressed air.
Replacing the measurement cell
Before disassebmling the detector it must be ensured that it is not under electric tension(plug removed). After the Allen screws visible at the end cap have been loosened they canbe removed using the spanner supplied.
The parts of the detector remain attached to each other as a result of the spring tension of
the plug even after the screws have been loosened. When reassembling the apparatus witha new measurement cell or one of the same type, alignment grooves and the position of theplugs aid the correct settings of the cell.

21The plug and socket strips of the electronic modules are protected against
accidental contact. When objects are inserted which conduct electrical current theelectronics can be damaged as a result of electrostatic discharge.

enmeasurement cellsize 3 Allen keyalignment groove

Fig. 9: Replacing the measurement cell

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Trouble shooting

The following table helps when correcting faults occuring in daily use

enError description

Possible cause

Explanations and action taken

Status indicator red

Measurement cell not detected

Make sure connector is plugged inInternal calibration defective

Inform customer service

Conductivity still shown Contact between cell andon display as zerodetector block broken
Contact within
the measurement cell broken

Make sure connector is plugged in
Replace measurement cell

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Error description

Possible cause

Temperature display still Contact between cell andshows 0 / 100 °C
detector block broken

Unstable or noisy
basis line

Explanations and action taken
Make sure connector is plugged in

Temperature sensor within themeasurement cell defective

Replace measurement cell

Bubbles in the solvent

Use degassed solvent

Measurement cell soiled

Rinse out the measurement cell with acleaning solution (see above) and switch
the equipment off and then on again.

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Annexe 1: Spare parts list
The spare parts listed can be ordered directly from Runge or one of Runge's distributors.
Part numberDesignation

81.240.0001

Measurement cell conductivity, analytic, 5 µl, Z=5/cm

81.240.0002

Measurement cell conductivity, analytic, 5 µl, Z=50/cm

81.240.0011

Measurement cell conductivity, preparative, 20 µl, Z=5/cm

81.240.0012

Measurement cell conductivity, preparative, 20 µl, Z=50/cm

00.321.0034

Knurled-head screw 1/4“-28 UNF for capillary tube OD=1/8“, PEEK

00.321.0035

Knurled-head screw 1/4“-28 UNF for capillary tube OD=1/16“, PEEK

00.321.0044

Ferrule for knurled-head screw 1/4“-28 UNF for capillary tube OD=1/8“

00.321.0045

Ferrule for knurled-head screw 1/4“-28 UNF for capillary tube OD=1/16“

81.6A0.1807.en

Operations manual mikron 81 Englishen

26Part numberDesignation

G2.241.0002

Short mikron table mounting

00.521.0001

spanner, size 3 Allen key

00.522.0001

USB-C to USB-A cable, length 1.5 m27Annexe 2: GLP detector specifications

Component

Specification

apparatus

serial number
firmware version
number of switching cycles
operating hours
date of last maintenance by customer service
date of last validity check

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For ordering and technical support, please contact:
Europe: Biotech AB Tel: +46 (0)300-56 91 80. info@biotechfluidics.com
USA: Biotech USA LLC Tel: +1 612 703 5718. sales@ biotechfluidics.com
www.biotechfluidics.com

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Conformity declaration
Manufacturer:

Wissenschaftliche Gerätebau „F. F. Runge“ GmbHDavid-Gilly-Straße 114469 Potsdam, Germany

Model:

conductivity meter mikron 81 (Typ 81)

We declare hereby that the preceding designated product conforms in its conception and type of construction andalso the design lauched on the market to following directives:
2014/35/EU
2014/30/EU
2011/65/EU
2012/19/EU
DIN EN 61000-3-2:2014
DIN EN 61010-1:2001
DIN EN 61326-2-3

Low-tension directive
EMC (electromagnetic compatibility) directive
Directive on the restriction of hazardous substances in electric and electronic equipment
Directive regarding waste electrical and electronic equipment (WEEE)Electromagnetic compatibility (EMC) directive – limits für harmonic current emissions
Safety requirements for electrical equipment for measurement, control, and laboratory use
EMC – Electrical equipment for measurement, control and laboratory use

Potsdam, 1st of March 2018
Ernst Eimer(managing partner)en30