Testing Refractive Index of Candy

Tech Challenge

Candice at Candy Coats has decided to start a quality control laboratory to standardize and monitor their candy products for consistency as they expand and produce more. She would like to test a sample of each finished batch of soft and hard candies for the refractive index (RI) in order to measure of the sugar content specifically. The RI is expected to be relatively high, around 1.5-1.7, and they have requested a high accuracy solution.

Which of the following would be the ideal refractometer?

A. Handheld RI refractometer (02940-09).

B. An Abbe refractometer (02940-04).

C. A digital RI pocket refractometer (81030-00).

D. A bench-top programmable digital refractometer (81100-30).

Answers:

A. A handheld Refractive Index refractometer (02940-09).
Incorrect. This instrument reads RI at a maximum of 1.52, so the range is not wide enough. Also, the accuracy is low: +/- 0.001 RI units.

B. An Abbe refractometer (02940-04).
Correct! This specialized refractometer is designed to read up to
1.71 RI units, it is very accurate (+/- 0.0001 RI units) and has been adapted to measure solids and semisolids as well as liquids.

C. A pocket Refractive Index digital refractometer (81030-00).
Incorrect. Although the accuracy is high (+/- 0.0001), this instrument has a narrow range (maximum RI 1.58).

D. A bench-top programmable digital refractometer (81100-30).
Incorrect. This instrument meets the requirements for the range (maximum RI 1.7) and the accuracy (+/- 0.0001), but fails in the final requirement. It only measures liquids.