Standard grading of laboratory chemicals

Laboratory chemicals play an important role in the chemical analysis, process development, quality-control, qualitative and quantitative estimation of elements, ions, molecules and compounds in clinical, pharmaceutical, metallurgical, chemical and allied industries.Chemical laboratories are an integral part of these industries and academic institutions which include schools, colleges, universities, engineering and technical institutions.

Laboratory chemicals also play a vital role in the agricultural development, which include fertilizers and pesticides. Besides chemical process and control laboratories, the laboratory chemicals are also required in pathological and metallurgical laboratories. Even process instrumentation, control and computer laboratories also use different types of laboratory chemicals. Hence, there is a high demand of laboratory chemicals in different industrial and academic institutions. Thus laboratory chemical industry plays an important role in the global economy, and it contributes around 6.7 percent to the GDP.

To sustain the Research and Development (R&D) works in various fields the use of laboratory chemicals is must. Laboratory chemicals are used in different grades based on the applications and requirement. Work in the chemical laboratory involves the use of inflammable solvents, some corrosive and toxic chemicals, and apparatus which, if used improperly, can cause minor to severe injury. All work with acids, base and some reactive chemicals must be performed in the fume hoods not on the tables.  A few seconds delay can result in very serious injury, every person in the laboratory. Adequate knowledge of these chemicals before stating laboratory work is essential.

Laboratory chemicals are categorized in different grades based on the impurity content and applications. This article discuss about the standard grading of the laboratory chemicals.

General chemicals
Some common laboratory chemical grades are listed in Table-1. The American Chemical Society has graded the highest purity chemicals as ACS grade, which are suitable for use in many laboratory and analytical applications.

Acid and base. The most commonly used laboratory chemicals are either acid or base. Both acids and bases are essential laboratory reagents, not only in chemical process laboratory but also in pharmaceutical, metallurgical and all other laboratories.

The general classifications of acids are based on source (i.e., organic and inorganic), strength, (i.e., dilute and concentrated) etc. Based on applications the acids used in laboratory are often grouped differently, as shown in Table-2.

Chromatography
Gas chromatography (GC), high performance liquid chromatography (HPLC), thin film liquid chromatography (TFLC) etc. are ultra-modern laboratory process, used for separating and analyzing small amounts of organic chemicals. These processes play very important role in developing various high end chemicals, viz. flavours and pharmaceuticals.

Agricultural and pesticides:  The term pesticide covers a wide range of compounds including insecticides, fungicides, herbicides, etc. Ideally a pesticide must be lethal to the targeted pests, but not to non-target species, including man. Unfortunately, this is not the case, so the controversy of use and abuse of pesticides has surfaced. The rampant use of these chemicals, under the adage, “if little is good, a lot more will be better” has played havoc with human and other life forms.

Standard Solutions: A standard solution is a solution whose concentration is known accurately.  A standard solution of accurately known concentration of chemicals viz. acid, base or a salt  prepared from a primary standard (a compound which is stable, of high purity, highly soluble in water and of a high molar mass to allow for accurate weighing) that is weighed accurately and made up to a fixed volume. Standard solutions play important roles in chemical analysis.

Standard normal or molar solutions are prepared with raw materials which meet or exceed requirements of the relevant standards. Where no standards are not available, chemicals of highest purity available are used. All aqueous solutions are prepared using high purity, de-ionized, water which meets ASTM type 1 Reagent Grade water specifications. These solutions are standardized direct to NIST standards or primary standard grade materials where available.