There are certain hindrances with using handheld refractometers, the main one being; obtaining an accurate measurement. When using an optical refractometer, one must place their sample on the prism and look through an eyepiece to determine the measurement of an index of refraction.
The use of a digital refractometer eliminates the uncertainty associated with optical refractometers; a digital refractometer uses an LED light to shine through the sample. When a liquid sample is applied to the measuring surface only some of the light is transmitted through the solution and is lost; while the remaining light is reflected onto a linear array of photodiodes creating a shadow line. The refractive index is directly related to the position of the shadow line on the photodiodes. Once the position of the shadow line has been automatically determined by the instrument, the internal software will correlate the position to refractive index, or to another unit of measure related to refractive index, and display a digital readout.
To learn more about Sper Digital Refractometers please watch this video
At Sper Scientific, we certify two categories of instruments:
- Newly purchased instruments are certified prior to shipment, which may extend your order ship day by up to 10 business days. Not all instruments can be certified, when certification is possible an ordering option will appear on the product page.
- Previously purchased instruments are returned annually to Sper Scientific for certification, and may take up to 10 business days to certify.
Purpose of the Program:
There is an increasing requirement by customers for documentation supporting manufacturer’s claims of accuracy on their scientific equipment. This is partially due to the increasing acceptance of quality standards, such as ISO 9000* and GMP**, which require that periodic certification of test equipment be performed and documented. Most testing is done in-house with our own state-of-the-art equipment. Whenever possible and practical, we use N.I.S.T. traceable equipment and N.I.S.T. procedures.
* ISO 9002 1987 (E) Section 4.10
** FDA Good Manufacturing Practices Section 820.61
Each certified product comes with:
• A serial number
• A calibration or certification label
• One of three certificates.*
For a complete list of certified products please go to www.sperdirect.com