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LABORATORY REAGENTS
There are five main grades of laboratory chemical i.e.
(i) Aristar
These are the purest grade of laboratory chemicals that is commercially available. They usually carry full specification, which includes
- The assay of the chemical.
- The molecular mass.
- The maximum and minimum limit of impurities.
- The physical constants e.g. the boiling and melting point.
This grade is very expensive and mostly used for research purposes.
(ii) Analar
These are the second purest chemicals available and it is the internationally recognized standard for laboratory chemicals. In fact, some of them are used for standardizing other laboratory chemicals.
They also carry full specification, which may include:
- The assay.
- The molecular weight.
- Maximum and minimum unit of impurities.
- Physical constants.
(iii) General purpose reagents (GPR)
They are the third purest grade of laboratory chemicals and are used for general analytical work, they also carry full specifications.
(iv) Laboratory reagent
They are intermediate in purity between GPR and technical grade. They sometime carry full specifications.
v) Technical grade
They are reagents that are carefully selected for specific jobs and they are subject to analytical control. They are mostly used for specialized technical analysis, they carry no specifications.