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Rudolph Research J 357 Automatic Brix and Refractive Index Refractometer


  • $ 2,99999
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Item Description: The J357 Series of Automatic Refractometers -Laboratory Flexibility with Industrial Strength and Simplicity The J357 Series of Automatic Refractometers


Product Specs:

Measurement Range:                         Refractive Index 1.26-1.72 / Brix 0-100

Accuracy:                                            Refractive index ±0.00002 / Brix ±0.015

Reproducibility:                                   Refractive index ±0.00002 /  Brix ±0.015

Resolution:                                           Refractive index 0.00001 / Brix 0.01

Temperature Control Range (°C)         10°C to 100°C 

Automatic Refractometer, J357 Offers Highest Performance for Research Labs.

Designed as a research quality instrument the Rudolph J357 Automatic Digital Refractometer offers one of the highest measurement ranges of any instrument in the Rudolph refractometer product line. This instrument offers the same extra wide RI measurement range as our chemical industry refractometer models combined with the high accuracy of our food industry refractometer models. It also offers very powerful automatic electronic temperature control (heating and cooling) and is able to make RI and BRIX measurements at up to 100 °C.  The J357 is a perfect choice for the most demanding pharmaceutical, chemical, petroleum, essential oils, fragrance and cosmetic refractometer users.


Simple Refractometer Operation

Operating the J357 Automatic refractometer is as simple as placing a sample on the artificial sapphire prism, closing the presser and reading the answer on the Digital Display — all in just a few seconds. There are no shadow lines to match and there is no eyepiece requiring any kind of operator determination or manual adjustment as is often necessary with ABBE Refractometers. When the “measure when stable mode” is selected, the J357 Refractometer automatically waits until the sample has been heated or cooled to a predefined temperature before initiating a measurement.

Interface Solutions

Full Display with Smart Measure

Load – and – Go Display

Trend Analysis Display

Trend Analysis – On-Board Data Collection and Specification Range Monitoring

Dual Electronic Temperature Control to 100 °C

Unlike other temperature controlled refractometers, the J357 has temperature control from both above and below the sample. 

Optional Sample Presser

Refractometer Calibration

The J357 offers 1 point, 2 point or a full multi-point calibration. Calibration can be done at 20°C, 25°C or any user selectable temperature within the available range. Regardless of how many times the refractometer has been calibrated, it can always be restored to the initial factory calibration if required.

On-Board Custom Scales

The J357 Refractometer is available with 100 possible programmable scales. Custom scales can be set up in a few minutes. Simply enter 2, 6 or 10 data points of concentration and corresponding RI (refractive index) value, press Compute and the instrument creates a new custom scale.

High Durability Sapphire Prism

An Automatic Refractometer that is Easy to Clean

User Interface

A large 7.5cm x 10cm cold cathode fluorescent backlit graphics, digital LCD allows the scale, sample temperature, set temperature, air temperature, time, date and temperature correction status to be easily viewed. All functions are activated through a touchscreen panel which will not wear out or be misplaced like traditional or detachable keypads. The digital touchscreen is resistant to fingernails, sharp objects, chemicals, and acids.

No Water Bath Needed

Having Rudolph’s J357 fully automatic electronic temperature control means:

  • A significant savings on bench space because the water bath is eliminated.
  • Integrated temperature control where the instrument knows when to measure and records both the Refractive Index measurement and the temperature.
  • Hot liquid from a bath can present a significant danger in the laboratory in the event of a split hose, the J357 doesn’t use liquid and thereby eliminates this risk.
  • Eliminating the water bath removes the most maintenance intensive part of a Refractometer. Water baths need to be regularly filled, dosed with algaecide and cleaned.

Traceability & 21 CFR Part 11 Compliance

Networking, Data Recording, and Data Management

The J357 offers several options for data storage. Data may be stored internally by means of an 8 MB Internal Compact Flash Memory, to a network via RS232, Cat 5 Network port, or via 3 rear and 1 side USB Ports. Storage options include writing and storing to a network, sharing to a LIMS system, and Storage to a removable USB drive.  For all data storage options see: Refractometer Data Storage


National Industrial Supply 
30777 Rancho California #891420
Temecula, CA 92589, USA
Sales: 951.308.9269
Fax: 310.733.5480  -  E-mail:  -  Website:

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