+44 (0)1487 814313 sales@indexinstruments.com

Incorporating electronic temperature control by Peltier Cell technology.....



The new PTR range of refractometers is the result of a combination of decades of experience in design and manufacture to provide our customers with state of the art refractometers that are accurate, reliable and simple to use. The PTR-300 series of Peltier temperature controlled refractometers comprises two standard models for single application measurement and a third model specifically designed for the sugar industry.  All models cover a wide measuring range, as is the requirement of the food, dairy, drinks, pharmaceutical, chemical, petrochemical, flavours and fragrance industries.  The PTR-300 series meets UK, European and US Pharmacopoeia and can be programmed to control data in accordance with FDA regulation 21 CFR Part 11, making it ideal for use in environments such as in the pharmaceutical laboratory.


A full colour programmable touch screen combined with a powerful microprocessor can display readings in a number of popular scales and the simple to use menu format can be displayed in a number of different languages.  Data can be output through either RS232, Bluetooth and USB, allowing connection to printers, computers and a serial output for an auxiliary item such as a bar code reader.


Wide range

All PTR-300 models operate over the wide refractive index (RI) range of 1.32 to 1.68.
The PTR-300 provides an accuracy of 1 in the 4th decimal place of RI over the full range. The PTR-300X model gives an enhanced accuracy to 5 in the 5th decimal place of RI over the range 1.32 to 1.45, with only slightly reduced accuracy to 1.68 RI.

Refractive index is measured by the 'critical angle' method, similar to the method used in a visual Abbe refractometer. As back reflected light is used, very dark or difficult samples such as chocolate sauce, coffee, honey and dairy products can be measured as easily as clear samples. The PTR-300 series have a special 'emulsion' mode to improve measurement of turbid samples.  All instruments have no moving parts, an almost indestructible sapphire prism and a sealed casing. They also offer a selection of optional sample cells, making the PTR both extremely versatile and capable of operating in harsh environments.

The PTR range has been engineered to operate in a wide range of ambient conditions. For more extreme conditions, an auxiliary heat sink is available to ensure accurate control when, for example, cold samples are to be measured in the higher ambient temperatures found in tropical climates.



A simple key press on the colour LED touch screen gives access to many popular scales; Refractive Index, Brix, Temperature Corrected Brix, Temperature Corrected RI, Zeiss, Butyro, HFCS(42), HFCS(55), Urine SG, Oechsle, Baume, Babo, NaCl (other scales can be programmed upon request), and up to 16 user programmable scales. You can also have a choice of 4 measuring modes: in 'Continuous' mode, the PTR reads in live time updating the display every 2 seconds. 'Single Scan' mode allows you to program the instrument to wait a pre-set time to allow for stabilisation and then to scan, display and hold the result. By selecting 'Autoprint' mode, the operator can set a time interval for automatic print-outs to monitor a change or flowing sample. In 'Stability' mode, the automatic measuring system within the instrument intelligently decides when the sample has come to a stable reading and only then outputs the result. The operator can set the level of stability to ensure that the accuracy required is obtained time after time, in the shortest possible time.

When required, a 'Qwerty' format keypad or a numerical keypad appears on screen for data and information entry for 'GLP' (Good Laboratory Practice). Time, date and instrument serial number can be output to a printer or PC together with every reading, and the instrument can also be set up to ask for a number, or up to 6 other parameters specified by the user, to fully identify the sample.  The titles of these parameters can have up to 20 characters (letters, numbers or spaces) and so can be in any language.

The new PTR-300 series have a range of special additional features too.  There is a simple routine to set the upper and lower warning limits for a particular material solution.  A second special feature is a routine for programming the instrument to calculate Average and Standard Deviation on readings and produce a small visual graph from the data in real time on the screen.  The PTR-300 series offers a  routine for setting a 2 point zero/scale length adjustment and a simple, one touch key selection for either ‘normal’ or ‘emulsion’ type sample mode.

Bluetooth for wireless connectivity to periphery devices such as PC’s and printers is provided together with USB, RS232 and serial ports at the back of the instrument.  The PTR-300 series can also communicate with Optical Activity’s latest range of polarimeters using Bluetooth technology, please contact Index Instruments for further details.  


Tel: +44 (0)1487 814313 Fax: +44 (0)1487 812789
Index Instruments Ltd. Bury Road Industrial Estate, Old Station Road,
RAMSEY, Huntingdon, Cambridgeshire, PE26 1NF, England

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