Calibration and Services
Polarimeter Calibration

Polarimeters are generally zero calibrated using air or distilled water. However, in some cases it is desirable to use an active blank solvent to zero the instrument, allowing further measurement to reflect any optically active component that is later added to the solvent.

Bellingham + Stanley do not supply any materials for zero calibration.

Sucrose Solutions of known concentration may be used to verify a polarimeter operated in either the angular or sugar scale. Sucrose solutions are primarily used in the sugar and food industries but are considered too time consuming to prepare, requiring a new sample to be made for each calibration as its optical rotation is affected by time. Sugar Solutions are also temperature dependant so it is desirable to use a temperature controlled polarimeter tube or employ temperature compensation if available.

Bellingham + Stanley offer a choice of Quartz Control Plates (QCP) for verifying and calibrating polarimeters. QCPs are made to the highest standard and are supplied with a Certificate of Conformity showing values at sodium and NIR for both angular and sugar scales.

In addition, QCPs may be supplied with an optional Certificate of Calibration, showing traceability to PTB.

When used with an ADP polarimeter manufactured by Bellingham + Stanley, a thermal block may be used to provide mechanical contact to the instrument’s external temperature sensor, allowing the use of quartz temperature compensation for added accuracy.

Order Code Nominal Value Description 34-20 +100 °Z +34.6 °A Standard Quartz Control Plate supplied in soft protective cover, Certificate of Conformity showing optical rotation in ° A & °Z for sodium and NIR wavelengths (only) and packed in a rigid case for transit and storage. 34-21 +15 °Z +5.2 °A 34-22 -30 °Z -10.4°A 34-241   Thermal Block for use with ADP/S Uncertainty (new plates): ±0.017 °Z and ±0.006 °A

Certification Service
Quartz Control Plates may be supplied from new with a traceable certificate, as an optional service. Additionally, as part of GLP, it is often required to have existing Quartz Control Plates recalibrated at regular intervals.

Bellingham + Stanley, a UKAS accredited Calibration Laboratory number 0834, offer a certification service whereby Quartz Control Plates may be issued with a UKAS Certificate of Calibration at sodium (589.44nm) wavelength and additionally at any other wavelength specified by the customer between 546-900nm, with traceability shown to ICUMSA and PTB. Plates outside of the ranges below may also be certified within the UKAS laboratory to an uncertainty of ±0.05 °Z (±0.017 °A)

Range ISS Angular 1 13 to 17 °Z 4.5 to 5.9 °A 2 95 to 105 °Z 32.9 to 36.4 °A 3 -26 to -34 °Z -9.0 to -11.8 °A Ranges 1-3: Uncertainty: ±0.017 °Z and ±0.006 °A In the Range -34 °Z to 105 °Z but outside of ranges 1-3: Uncertainty: ±0.05 °Z and ±0.017 °A

Order Code Description 90-803 Calibration, quartz control plate at 20.0 °C & 589.44nm. 90-805 UKAS Certificate of Calibration for Quartz Control Plate at 20.0 °C Any additional specified wavelength 546-900nm other than 589.44nm, per unit (i.e. each wavelength specified). Must be ordered in addition to Certificate of Calibration at sodium wavelength (589nm – Code 90-803)

Best Measurement Capability (Uncertainty):
The reported expanded uncertainty of measurement is stated as the standard uncertainty of measurement in units of °Z multiplied by the coverage factor k = 2, which for a normal distribution corresponds to a coverage probability of approximately 95%. The standard uncertainty of measurement has been determined in accordance with publication EA-4/02.

 

Technical Bulletion TB-003 – Calibration of Polarimeters using sucrose.