Acid Dye Method for the Analysis of Thiamine

Comparative study of colorimetric and fluorometric determination of thiamine(vitamin B1) by an automated discrete-sampling technique

“…All chemicals used were ACS certified reagent grade. Necessary reagents for the colorimetric method were prepared according to the procedure given by Das Gupta and Cadwallader (7). Detailed procedures for reagent preparations described in U.S. Pharmacopeia XVIII were followed for the thiochrome method.…”

“…This method is most widely used for thiamine determination in pharmaceutical quality control laboratories (6). Although the fluorometric method is the most specific of all the methods in general use for thiamine determination, the need to give close attention to the details of the procedure detracts from its use for rapid control work (7). On the other hand, while colorimetric methods receive very little attention, a promising colorimetric method utilizing the basicity of thiamine has been reported recently by Das Gupta and Cadwallader (7).…”

Interaction between bromothymol blue and antipyrine in dichloromethane

“…Bromothymol blue is the most widely used dye for the determination of amines of pharmaceutical interest by photometric titration in two phases (1)(2)(3)(4)(5)(6)(7). The amine -bromothymol blue reaction has been described as a non-specific acid-base process in one non-polar phase (8,9), and in two non-miscible phases (1)(2)(3)(4)(5)(6)(7).…”

“…The amine -bromothymol blue reaction has been described as a non-specific acid-base process in one non-polar phase (8,9), and in two non-miscible phases (1)(2)(3)(4)(5)(6)(7). However, the reaction is not totally non-specific because some amines give practically no reaction either in one or two phases, such as the benzodiazepines medazepam and bromazepam (9,10).…”

Competitive Protein-binding Radioassay of Thiamine in Simple Solutions and in Multivitamin Pharmaceuticals

“…The method is sensitive and applicable to a broad range of various materials. For samples of relatively high thiamine concentration, like pharmaceutical preparations, several other chemical procedures are of choice for thiamine assay, including colorimetry (Das Gupta & Cadwallader 1970), UV absorptiometry (Strohecker & Henning 1966), polarography (Vergara et al 1980), potentiometry (Hassan et a1 1985) and gas chromatography (Echols et a1 1985).…”