Rudolph J257 & J357 Refractometer

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The Rudolph Research J257 Wide Range Refractometer was developed by working together with laboratory refractometer users from the polymer, petroleum, petrochemical, pharmaceutical and essential oil industries.

The J257 is a fully Automatic, Digital Refractometer, featuring electronic cooling and heating with an extended Refractive Index (RI) measurement range.

  • Wide refractive index range of 1.26-1.72 measures beyond instruments with only a food refractive index range of 1.33-1.53
  • Measures aromatic essential oils, fluorocarbon solvents, and all known materials.
  • Large, easy to read, 7.5cm x 10cm cold cathode fluorescent back lit, digital LCD Screen


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.

  • Dual Electronic Temperature Control  – Range 15ºC – 100ºC or 10ºC – 120ºC (optional)
  • Accuracy: ±0.00004 RI, ±0.03 BRIX
  • High Durability Sapphire Prism
  • Data Storage: Removable media card or upload via RS 232 to LIMS systems



( Download data sheet)