Measurement Modes
The Autopol IV laboratory polarimeter provides direct readout in one of four measurement modes: optical rotation, specific rotation, concentration or specific rotation plus.

  • Specific rotation plus allows a correction to be applied to a result for loss on drying
  • Each measurement mode can be selected using the touchscreen
  • Any length of sample tubes can be specified (e.g. 50mm, l00mm or 200mm) or entered as a precise dimension such as, 199.98mm
  • Concentration is entered as a percentage

Temperature Control
Temperature control of samples is facilitated through rubber gasketting in the Autopol door. This allows tubing to be connected from an external temperature controlled water bath to a jacketed polarimeter sample tube.

Some manufacturers polarimeters can only accept special sample cells with maximum lengths of 100mm. Autopol polarimeters can accommodate standard sample cells up to 200mm long, offering twice the sensitivity as the same solution in a 100mm cell. Especially useful for solutions having small rotations. Some pharmacopoeia monographs like the USP monograph for Methotrexate require a 200mm (2dm) cell. Rudolph Research polarimeter sample cells are made to NIST standards and NIST certificates are available for cell length validation.

Sample Specific Programs
These programs allow for parameters such as tube length, concentration, specific rotation, wavelength, sample measurement range, measurement scale and temperature correction to be pre-specified. The programs can be labelled with an alphanumeric name (e.g. Dextrose 2).Simply select the sample program from the alphabetic list and the Autopol polarimeter is ready to make measurements.
Sample specific programs can be set to read optical rotation, specific rotation, concentration or user defined scales. A user defined scale is a linear equation based on the measured value and input parameters. Multiple Wavelength selection on the Autopol IV is completely automatic and is accomplished via menu selection. There are no lamps or filters to manually remove or insert. Available wavelengths are 365nm, 405nm, 436nm, 546nm, 589nm and 633nm. Optional wavelengths include: 325nm, 578nm and 880nm.

The mean and standard deviation are calculated and the minimum and maximum readings recorded for up to 999 measurements. Measured data for statistical calculation can be printed automatically, at predetermined time intervals or manually. Statistics for a batch of samples can be produced using the page feed key. Statistics on time varying optically active samples can be compiled by measuring a sample at a predetermined rate and for a predetermined number of measurements.

Range Limits
Sample range limits are specified in sample specific programs, (e.g. 24.8° Arc – 25.7° Arc). When a range is specified and the measurement falls outside this specification the display will read “out of range”. Two TTL level signals are available for out of range conditions. These signals are useful for process control or alarms.

Subscribe to the QCL Polarimetry,Refractometry and Density Newsletter