Commercial assays

In genotoxic assays, commercial hexane, consisting of -hexane and other six-carbon isomers, did not produce chromosomal mutations either in vitro or in vivo Results have generally been negative in bacterial assays and in other mammalian cell assays. Morphologic alterations in sperm were noted in one inhalation study in rats. ... 

Guidance for ELISA, HPLC, GC, Validated assay Commercial... 

Different laminated structures are constructed by arranging the functional layers according to the requirements of the chemical or biochemical assay. Commercially available assays include those for creatinine, albumin, amylase, bilirubin, cholesterol, triglycerides, and certain alkali and alkaline earth metals. 

Assays for uEs are calibrated by use of chemically pure estrioi. Estrioi values can be reported in mass units (nanograms per milliliter or micrograms per liter) or SI units (nanomoles per liter). The equation for converting mass to SI units is Inmol/L = 3,47ng/mL - 3.47]U,g/L, Although pure UE3 is available for calibrating UE3 assays, commercial kits yield values on clinical specimens that can differ by factors of 2 to 3. 

The water used in making all solutions was prepared using 10 MOhm water. Stock solutions of sodium silicates were made from carefully assayed commercially available solutions for ratio (w/w) values of 2.0 and 3.8 and from sodium metasilicate and NaOH for the 0.5 ratio solution. 

The simphcity of this technique, its high-throughput capability, and its ability to often predict passive intestinal absorption (see below) have combined to make it a very popular assay. Commercial instruments are usually employed. At some companies, these days, the assay may be run on most compounds made during drug discovery, providing rapid feedback on transcellular passive diffusion, which is, as we ve seen, an important component of intestinal absorption. 

PURPOSE OP EXPERIMENT Prepare aspirin, determine its molecular weight by freezing point depression, and assay commercial aspirin by titration with NaOH. 

ITormandy s STethod.—Dr. Normandy gives the fol lowing method of assaying commercial soda and potash —... 

Commercial acetaldehyde has the following typical specifications assay, 99% min color, water-white acidity, 0.5% max (acetic acid) specific gravity, 0.790 at 20°C bp, 20.8°C at 101.3 kPa (1 atm). It is shipped in steel dmms and tank cars bearing the ICC red label. In the Hquid state, it is noncorrosive to most metals however, acetaldehyde oxidizes readily, particularly in the vapor state, to acetic acid. Precautions to be observed in the handling of acetaldehyde have been pubHshed (103). 

Manufacture. Commercial KF is manufactured from potassium hydroxide and hydrofluoric acid followed by drying ia a spray dryer or flaking from a heated dmm. The KF assay is typically 97—99% impurities are KF 2H20 and either potassium carbonate or potassium bifluoride. The 1992 price of... 

Hybrid probe—immunoassays are expected to find a specific niche in clinical analysis, especially as a means to adapt probe assays to existing immunoanaly2ers which are locked into a specific enzyme or fluorescence detection technology. Commercialization of the first of these assays is expected by the year 2000. 

Typical physical properties and assays of the commercially most important alkylphenols in terms of worldwide volume were given in Table 1. 

The cmde product formed from the alkylation of phenol with isoamylene contains principally 2-/ r2 -amylphenol, 4-/ r2 -amylphenol, and 2,4-di-/ r2 -amylphenol. 4-/ r2 Amylphenol is purified to its typical assay of 99+% by fractional distillation. 4-/ r2 -Amylphenol [80-46-6] is commercially available as a soHd, flaked material packaged ia paper or plastic bags (25 kg net weight) or as a molten material ia tank wagon or railcar quantities. 

The 4,4 -MDA is sold commercially with a diamine assay of 98 —99%. The major impurity is the 2,4 -MDA isomer, which can be present in amounts up to 3%. PMDA products are normally defined by hydrogen equivalent weight and viscosity. Typical products exhibit a 50 hydrogen equivalent weight and a viscosity of 80 140 mPa-s(=cP) at 70°C. PMDA products normally contain, in addition to the isomers and oligomers of MDA, small amounts of aniline, water, chlorides, and various alkylated amines. AH MDA products should be stored in sealed containers in a cool dry area. 

Methyl salicylate is produced synthetically for commercial purposes by the esterification of salicylic acid with methanol or by extraction by steam distillation of wintergreen leaves or sweet birch bark. The source, natural or synthetic, is declared on the label. The methyl salicylate NF must assay not less than 98.0% and not more than 100.5% and be processed by Good Manufacturing Practice described in USP (20). 

Grades ndSpeciEca-tlons. A technical crystal of 98% minimum assay with ca 2 wt % maximum water content is commercially available, as well as a 50—55 wt % aqueous solution (375,376). The latter is the predominant product. 

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