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Refractive Index Fluids
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Brix Fluids
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Advantages
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Description of Fluids
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Refractive index fluids are made from chemical compounds such as methylene iodide, silicon oil and alpha bromonapthalene. These chemicals are chosen as they are non toxic though some of the fluids do have an unpleasant odor (alpha bromonapthalene = mothballs).
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Brix fluids are a mixture of sucrose and water.
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Brix fluids
They are so safe you could drink them. They are just sugar and water.
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Traceability of Fluids
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Refractive index fluids are provided with a certificate showing traceability to a national standards body – NIST.
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Brix fluids are made using the method specified in ICUMSA and are provided with a non-traceable certificate of analysis.
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Refractive Index fluids
NIST traceability is the ultimate US standard.
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Shelf Life
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Refractive index fluids have a rated life of 5 years unopened, 2.5 years opened. Care should be taken that they are not frozen, but otherwise they can be stored at room temperature.
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Brix fluids have a life of 30 days and must be kept refrigerated.
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Refractive Index fluids
Stored at room temperature for 2 years.
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Clean Up
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After calibration with the refractive index fluids the refractometer must be cleaned with an organic solvent such as acetone.
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After calibration with the Brix fluids the refractometer can be cleaned with water.
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Brix fluids
No toxic solvents needed
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Range
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Refractive index fluids are available over the full range from 1.30 – 1.70 Refractive Index and 0 – 95 Brix.
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Brix fluids are available over the range 0 – 67.5 Brix.
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Refractive Index fluids Wider range of calibration options
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Temperature Dependency
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All fluids are temperature dependent. The refractive index fluids have a different temperature dependency than the temperature compensation setting on a refractometer and so can only be used on a temperature CONTROLLED refractometer.
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Brix fluids have the same dependency as a temperature compensated refractometer and so can be used on any instrument.
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Brix fluids
They can be used to calibrate hand refractometers as well as bench models.
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