A simple method for the spectrophotometric determination of cephalosporins in pharmaceuticals using variamine blue

A simple spectrophotometric method for the determination of cefotaxime, ceftriaxone, cefadroxil and cephalexin with variamine blue is presented. The determination is based on the hydrolysis of β-lactam ring of cephalosporins with sodium hydroxide which subsequently reacts with iodate to liberate iodine in acidic medium. The liberated iodine oxidizes variamine blue to violet colored species of maximum absorption at 556 nm. The absorbance is measured within the pH range of 4.0-4.2. Beer’s law is obeyed in the range of 0.5-5.8 μg mL–1, 0.2-7.0 μg mL–1, 0.2-5.0 μg mL–1 and 0.5-8.5 μg mL–1 for cefotaxime, ceftriaxone, cefadroxil and cephalexin respectively. The analytical parameters were optimized and the method is successfully applied for the determination of cefotaxime, ceftriaxone, cefadroxil and cephalexin in pharmaceuticals.

A new method in estimation of total hexavalent chromium in Portland pozzolan cement

Variamine blue was used first time for the detection of hexavalent chromium from cement samples. In present method, cement was treated sequentially with water, sulphate and carbonate buffer to extract soluble, sparingly soluble and insoluble hexavalent chromium respectively. Extracted Cr (VI) was determined using variamine blue as chromogenic reagent. The determination is based on the reaction of hexavalent chromium with potassium iodide in an acid medium to liberate iodine. This oxidizes variamine blue to form a violet coloured species having an absorption to maximum at 556 nm. Energy-dispersive X-ray spectroscopy (EDX) and Infrared Spectroscopy (IR) confirmed the complete extraction of hexavalent chromium by sequential extraction process. SRM 2701 (Reference material from NIST, USA) was used for revalidating the results. The percentage of recovery for proposed and reference method (diphelycarbazide method) varied from 98.5 to 101 and 97.5 to 100.5. Whereas, their relative error percentage varied from -1.5 to 0.33 and -2.5 to 0.5.

Electrochemical Polymerization of Variamine Blue Film at Glassy Carbon Electrode and its Electrochemical Behavior

Variamine blue (VB) polymer coatings can be obtained by electrochemical polymerization at glassy carbon electrode. The electrochemical behavior of this stable polymer film at glassy carbon electrode was investigated by cyclic voltammetry. The surface coverage, Γ,the charge transfer coefficient, α , and the charge transfer constant, ks, for electron transfer between VB and glassy carbon electrode were calculated as 9.0×́10-5 mol·cm-2, 0.47, 2.97 s-1 respectively. This VB polymer coatings modified electrode shows good electrocatalytic activity toward ascorbic acid (AA), uric acid (UA). It can be used in simultaneous determination of AA and UA in a mixture.