User:Ooogaboooga 101/Chemical purity

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In chemistry, chemical purity is the measurement of the amount of impurities found in a sample. Chemical purity is determined by a number of tests. The degree of testing on a sample, and by whom, depends on the intended application of the compound. These degrees are measured in grades. There are several grades of purity used across the scientific, pharmaceutical, and industrial communities. Grades are made from a variety of different industries, each with their own form of testing and qualifications determined by the intended use of the compound. These details are typically outlined in a monograph, provided by the industry that set them.

These are some key types of grades:

Laboratory: These grades are used for a variety of different purposes across chemical analysis and laboratory settings. They include:


 * ACS grade meets the standards set by the American Chemical Society (ACS), purity ≥ 95% . The official descriptions of the ACS levels of purity is documented in the Reagent Chemicals publication, issued by the ACS. It is suitable for food and laboratory uses.
 * HPLC is used in high performance liquid chromatography. This is a high purity grade for liquid analysis and separations, purity ≥ 99%.
 * Puriss grade (also known as "Ultra-pure grade" ) is purity, ≥ 98.5%. Typically used in chemical trace analysis as impurity exists at ppb or ppt.
 * Purum grade (also known as "Synthetic grade") has purity, ≥ 95%. Typically for laboratory synthesis and testing.
 * Reagent grade is high purity without specifications, almost as stringent as the ACS grade.
 * Laboratory grade is suitable for use in educational settings, but is not acceptable for food or drug use. This is due to the presence of unknown exact amount of impurities in samples.
 * Purified grade is not precisely defined, best used for educational purposes and is not suitable for drug or food usage. Also known as "practical grade".

Industry: These grades are used for a variety of industrial applications, or are grades set by companies that sell reagents. They include:


 * Technical grade is suitable for industrial applications, but is not acceptable for food or drug use. This is due to higher levels of impurities, purity ≤ 80-90%.
 * Food grade is safe to be used when coming in contact with food. This includes in food or in cleaning products used in kitchens.
 * Fischer grades are set by Fischer Scientific, a laboratory company with their own set of product grades.
 * Sigma Aldrich grades are set by Sigma Aldrich, a laboratory company with their own set of product grades.
 * OmniTrace Acids is a grade set by EMD Millipore with high purity for trace metal analysis. Impurities existing in ppb.
 * Gas grades typically exceed most other purity grades, with high purity industrial gases having purity ≥ 99.999%. Some requiring impurities must be <0.1 ppm, as even impurities of 1 in 1012 can cause bad performance and yield in certain systems requiring these gases.

Pharmaceutical: These grades are typically applicable as well in laboratory settings but they are specifically graded for usage in pharmaceuticals. They include:
 * USP grade meets or exceeds the purity levels set by the United States Pharmacopeia (USP). Acceptable for use in medical, food, and drugs.
 * NF grade is a purity grade set by the National Formulary (NF). Details outlined in a joint USP-NF publication.
 * British Pharmacopoeia meets or exceeds requirements set by the British Pharmacopoeia (BP). Can be used for food, drug, and medical purposes, and also for most laboratory purposes.
 * Japanese Pharmacopeia meets or exceeds requirements set by the Japanese Pharmacopoeia (JP). Can be used for food, drug, and medical purposes, and also for most laboratory purposes.
 * European Pharmacopeia meets or exceeds requirements set by the European Pharmacopoeia (EP). Can used for food, drug, and medical purposes, and also for most laboratory purposes.

Determining which grade is most suitable, depends on the application of the compound. Depending on the situation, a grade with higher purity may not necessarily be better than one with slightly lower purity. A number of factors go into determining the right grade for each situation. This includes persons intended compound application, setting, budget, and required quantity. Sometimes it isn't even necessarily about the purity of the compound, it's about the type of impurities present in the sample. Depending on the application, higher concentration of one impurity won't affect much compared to a low concentration of a completely different impurity. This is why it's incredibly important to consider all these factors when determining the ideal chemical purity for each application and if, or when, appropriate substitutions can be made. Always ensure you are buying chemicals from a reputable source with legit certifications and gradings. Ensuring there is a Safety Data Sheet (SDS) and Certificate of Analysis (CoA) before purchasing.