Calibration of analysis devices

A matter for specialists• Pure and ultra-pure water: on-site calibration of conductivity/resistivity measurements in accordance with

USP recommendations and the ASTM standard

• Reference solutions directly linked to national and international standards for pH and conductivity measurements

• Metrological competence covering many other parameters (e.g. turbidity, chlorine, dissolved oxygen, nitrate)

Instruments International

Endress+Hauser Instruments International AGKägenstrasse 24153 ReinachSwitzerlandTel. +41 61 715 81 00Fax +41 61 715 25 00http://www.endress.cominfo@ii.endress.com

Other locations

Please visit: www.endress.com/worldwide

IN00107H/29/EN/01.06PF/INDD CS4

sterile

PARA M

MEAS CAL

DIAG

PARA M

MEAS CAL

DIAG

3m max. Sampling valveSampling outlet

Concal reference toolConductivimeter

The importance of analytical measurement is widely recognised in many production sites. These parameters are essential for monitoring the quality of the aqueous solutions used in manufacturing processes.Therefore, to ensure the reproducibility of a pH measurement or of conformity of a conductivity measurement in relation to manufacturing requirements (FDA or European Pharmacopoeia), it is very often necessary to carry out periodically calibration.

Calibration of analysis devices

Conductivity: a specialist matterCalibration of a conductivity measurement chain is usually carried out using an associated reference solution. For values between 0 and 20µS/cm, it is very rare and often impossible to find reference solutions because they become unstable simply by coming into contact with ambient air.

That is why a specific procedure has been defined and described in the ASTM5391 standard, using a comparative measurement against a specific reference system that is linked to international standards. Calibration is carried out by taking a sample equipped with a quick-coupler (e.g. clamp)

Measuring principle Conductivity pH

Place of calibration On-site On-site

Calibration range 0 to 20 µS/cm 70 µS/cm to 2 S/cm 0 to 14 pH

Equipment concerned

Conductivity or resistivity measurement chain

Conductivity measurement chain

pH measurement chain

Calibration method*

By sampling. Comparative measurement

comparative to a reference measurement chain +

control of the transmitter input signals (for USP or

European Pharmacopoeia conformity)

Measurement comparative to a

known conductivity reference solution

Measurement comparative to buffer solutions

Number of calibration points

1 point at the nominal use value

1 point at the reference solution

value2 points

Resources used

• Endress+Hauser reference measurement chain called Concal

• Precision decade box

Accurate solution with temperature

compensation table delivered with quality

certificate

Accurate buffer solutions with

cross table based on

temperature of use

Metrological compliance

To national and international standards

Linking of the solution to the SRM of NIST

To national and international standards

Documents issued

• Calibration certificate• On request, copy of

the proof of conformity to national/international standards

• Calibration certificate• On request, quality

certificate of the reference solutions used

• Calibration certificate• On request, copy of

the proof of conformity to national/international standards

located on the purified water pipe.The procedure applied and the tools used ensure the service is fully compliant with USP requirements stipulated by the FDA or European Pharmacopoeia.

* The calibration method applied in measuring conductivity up to 70µS/cm depends on the type of equipment used (cell constant) and your application (nominal value of the environment measured)