Abstract

A COMPREHENSIVE REVIEW OF DRUGS DETERMINED BY SPECTROPHOTOMETRY USING NQS AS A CHROMOGENIC REAGENT IN THE PAST DECADE

Seetha Mahithavani and Barla Karuna Devi*

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Abstract

Spectrophotometry with NQS (N-(1-Naphthyl)ethylenediamine dihydrochloride) is commonly used to measure the concentration of substances like nitrites or certain drugs in a solution. When the analyte (such as nitrites) reacts with the NQS reagent, it forms a colored complex. This complex absorbs light at a specific wavelength, and the intensity of this absorption is directly related to the concentration of the analyte. A spectrophotometer is used to measure how much light the solution absorbs at that wavelength. By comparing this absorbance to a known calibration curve, the concentration of the analyte can be determined. This method is effective and precise for measuring substances that react with the NQS reagent.1,2-Naphthoquinone-4- sulfonic acid sodium salt (NQS) is a widely used chromogenic reagent in analytical chemistry, particularly for the spectrophotometric determination of pharmaceutical amines. Its popularity stems from its efficient reactivity with both primary and secondary amines, forming colored complexes that can be quantitatively analyzed.

Keywords: Spectrophotometry, 1, 2 Napthaquinone 4-sulphonate sodium (NQS).