AUTOPOL IV, Laboratory Polarimeter, for Chemical and Pharmaceutical Labs

The AUTOPOL IV is a microprocessor based automatic polarimeter that is available in one, two and six wavelength versions. The AUTOPOL IV’s features include: readout in Specific Rotation, Optical Rotation, and concentration, customer defined and labeled programs for push button readout, large LCD display and touchscreen user interface, temperature display and correction, push button wavelength selection, statistics, 3 USB ports, RS 232 and parallel printer ports.

Measurement Modes

The AUTOPOL IV Laboratory Polarimeter can readout directly 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 activated via touchscreen selection. Sample tubes can be specified at any length (e.g. 50mm, l00mm, 200mm), or entered as a precise dimension (e.g., 199.98mm). Concentration is entered as a percentage.

Temperature Control of Samples in a Laboratory Polarimeter

Temperature control of samples is allowed through rubber gasketting in the Autopol door, which permits tubing to be connected from an external temperature controlled Water Bath to the jacket of a jacketed polarimeter sample tube.

Laboratory Polarimeter Cells up to 200mm Long

Instruments of some manufacturers accept only special sample cells, with maximum lengths of 100mm. Autopols accept standard sample cells up to 200mm long. A 200mm sample cell offers twice the sensitivity as the same solution in a 100mm cell. This is especially useful for solutions having small rotations. Also some pharmacopeia monographs require a 200mm (2dm) cell like the USP monograph for Methotrexate. Rudolph Research Laboratory Polarimeter sample cells are made to NIST standards; and the complete range of sizes and types are listed in Technical Bulletin 913. 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 labeled with an alphanumeric name (e.g. Dextrose 2). The operator simply selects the sample program from the alphabetic list and the AUTOPOL’s is ready to make measurements. Sample specific programs can be set to read either 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 Wavelengths

The AUTOPOL IV Automatic Polarimeter comes in single, dual and six wavelength models. Wavelength selection is completely automatic and is accomplished via menu selection. There are no lamps or filters to manually remove or insert. The following wavelengths are available: 365nm, 405nm, 436nm, 546nm, 589nm and 633nm. Optional wavelengths include: 578nm, 880nm and various other wavelengths are available; contact the factory for more information.

White-light Source Permits Spectral Versatility

The tungsten-halogen lamp employed in AUTOPOL Polarimeters is a compact, reliable,  low-cost, high intensity light source that allows any desired wavelength in the visible spectrum to be selected by means of a narrow band multilayer interference filter. The AUTOPOL standard 10nm bandwidth is specified to permit high energy throughput and sensitivity for sample transmittances of only 0.01 % (O. D. = 4), while minimizing the effects of sample ORD and color.

Temperature Display and Correction

The AUTOPOL IV Automatic Polarimeter comes standard with a temperature probe which can be inserted into the Polarimeter cell as shown to the left. The temperature of either the sample compartment or the solution itself can be continuously displayed.

Print Format

Numerous parameters, such as sample name, tube length, concentration, wavelength, time and date, temperature correction and statistics can be printed after each polarimeter measurement or after a group of measurements. This is accomplished by designating the required parameters, via menu entry, during the print format setup mode. A sample printout is shown below.

USB, RS 232, and Printer Communication

The AUTOPOL IV Polarimeter offers three USB ports, two RS 232 serial ports, and an Ethernet port for connecting to your network. The RS 232 port allows data to be sent to a computer when the print key is pressed, when the computer requests the data or at predefined time intervals. Measurements can be remotely controlled from a host computer and the printout format and parameters can be selected via menu entry. Utilizing a USB port, all plug-and-play Windows compatible printers may be added.

Real-Time Clock

AUTOPOL IV contains a real-time clock that tracks time and date. All measurements can be date and time stamped when printed out. The time is continually displayed in the upper right hand corner of the display.


AUTOPOL IV calculates the mean, the standard deviation and records the minimum and maximum readings for up to 999 measurements Measured data for statistical calculation can be printed in either one of two ways: automatically, at predetermined time intervals or manually, by pressing the print key. Statistics for a batch of samples can be accomplished by pressing 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 can be 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.


No matter which Autopol automatic polarimeter you choose, Rudolph uses the same high quality optics. While other manufacturers use Polaroid Plastic Dichroic Sheet Polarizers, Rudolph does not. Instead, Rudolph uses the same high quality Glan Thompson Calcite Polarizers in all its models.

Why are high quality polarizing prisms important? Because prisms are two of the most critical optical components in the polarimeter. Polaroid polarizers are made of a polymeric plastic where the molecules are stretches and oriented in a specific direction so as to linearly polarize light. These types of plastic sheet polarizers are very inexpensive ($50.00 USD) and are vulnerable to heat, warp over time, deterioriate from moisture, and also have greater light absorption than Calcite Polarizers. In many cases, the plastic polarizers must be replaced in 3 – 5 years. Glan Thompson Calcite Polarizers are comprised of a carbon crystalline structure similar to diamond and have excellent light transmission characteristics. The quality of these prisms is so good, Rudolph guarantees its prisms over the life of the polarimeter.

Polarimeter Calibration and Validation

Rudolph understands that today’s cGLP/cGMP laboratories must validate measurement and temperature. Therefore Rudolph offers 6 different NIST Traceable Quartz Calibration Standards that can be matched to your application. The Autopol IV also comes with a Temperature Validation Cell so that your temperature measurement can be traced to NIST. See Technical Bulletin 913 for more information.

Rudolph PC Software

This software offers a simple, easy to use interface for collecting data from Rudolph Polarimeters. Rudolph PC is available in several different versions, including PC Basic, PC Purity, PC Sample Handling, and PC 21CFR Part 11; there is a version of Rudolph PC software available for all of our polarimeters. All data can be exported to Excel with the click of a button.

Optional on the AUTOPOL IV Automatic Polarimeter — TempTrol™ Electronic Temperature Control System

The TempTrol™ System allows push-button temperature control of your TempTrol™ 100mm cell, 200mm cell, or Quartz Control Plate. Set the temperature, push “measure” and walk away. The AUTOPOL IV will heat or cool to a predefined temperature and then provide you with the result, all in one easy step.

The TempTrol™ System will accurately control your sample temperature to within ±0.2°C.


All Rudolph Instruments carry our exclusive 20 Commitment to service your instrument.

Rudolph Research Analytical offers a comprehensive range of Preventive Maintenance and Service Programs. Rudolph has demonstrated a commitment to its customers by keeping installed instruments operational, not only for 20 years, but in some cases for over 40 years. This long-term commitment to keeping our instruments running makes the cost of ownership, over the life of a Rudolph Instrument, one of the lowest in the laboratory market segment. At the date this document was published, there is no other laboratory instrument manufacturer guaranteeing service and technical support for 20 years. View the entire 20 Service Guarantee. 


Autopol IV – Specifications

AUTOPOL IV Specifications
Measuring Mode

Optical Rotation
Specific Rotation
Specific Rotation Plus Concentration
User Defined Scale
Sugar Degrees

Measuring Scale

Degrees Arc Optical Rotation


0.001° Arc Optical Rotation 0.001% Concentration 0.001 Specific Rotation


0.002° up to 1°, 0.2% up to 5°, 0.01° above 5°

AP Accuracy Option

Autopol IV Single ±0.002° Arc Optical Rotation
Autopol IV Dual ±0.002° Arc Optical Rotation
Autopol IV Six Wavelength Accuracy (546nm and 589nm): ±0.002° Arc Optical Rotation

AP Resolution Option

Selectable Resolution: 0.01, 0.001, 0.0001° Arc


0.002° Arc Optical Rotation

Measuring Range

± 89° Arc Optical Rotation,
± 999.99 Specific Rotation,
0-99.9% Concentration


Glan Thompson Calcite

Optical Wavelengths

365nm, 405nm, 436nm, 546nm, 589nm, 633nm

Wavelength Selection

Touchscreen Selectable: 1, 2 and 6

21 CFR Part 11 Compliant Software

Yes with optional PC software

Temperature Control

By external water bath (Standard)
TempTrol™ Automatic Electronic Heating & Cooling 15° – 40°C
±0.2° (Optional)

TempTrol™ Accuracy

±0.2°C (optional)

Temp. Probe Range


Temp. Probe Accuracy


Measurement Time

4°/sec slewing rate &
5 sec nominal settling time

Light Source

Tungsten-Halogen 6V, 20W, Avg. 2,000 hr. life

Sample Chamber

Accepts sample tubes up to 200mm

Data Storage

8 GB Non-removable Compact Flash

Communication Interface

3 - USB Ports, 2 - RS232 Ports, Ethernet Port for Network Connection


Automatic calibration via touchscreen

Operating System

Windows 7 Embedded


8 inch Color, 800 x 600 pixel resolution with 400 nits of brightness.

User Interface


Automatic Sensitivity Control

Measures samples with transmittance as low as 0.01% (up to O.D. 4.0)

Input Power

100 - 240V, 50/60Hz

Operating Dimensions

30"W x 11.5"H x 17"D,
762mm W x 431.8mm H x 279.4mm D

Shipping Dimensions

42"W x 24"H x 21"D,
1066.8mm W x 609.6mm H x 533.4mm D

Operating Weight

85 lbs (39 kg)

Shipping Weight

115 lbs (52.1 kg)

Temperature Compensation

Temperature of the sample can be corrected to a reference temperature


Battery-backed clock. Time and date sent to computer and printer