Cargille refractometer standards come with a letter of NIST traceability certification. Calibrate your refractometer with either oil or water.
Cargille refractive index oil is standardized at 589.3 nanometers (D line) and 25°C and has temperature coefficients and dispersion values listed on the label.
Cargille refractive index certified water uses ACS reagent grade water measured for refractive index at 589.3 nm on a high precision Pulfrich, standardized with NIST traceable standards.
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