Determination of Trace Amounts of Copper(II) by Using Catalytic Redox Reaction between Methylene Blue and Ascorbic Acid

Abstract

A sensitive and selective kinetic-spectrophotometric method is proposed for the determination of µg mL -1 amounts of Cu 2+ based on its catalytic effect on the oxidation of L-ascorbic acid by Methylene Blue in a strongly acidic medium. The reaction is monitored spectrophotometrically by measuring the decrease in color intensity of Methylene Blue at 665 nm. The analysis of Cu 2+ ion is performed by a fixed-time method. At a given time of 2 min at pH 2.20 and 32˚C, the detection limit is 10 ng mL -1 and the relative standard deviation for 0.4 µg mL -1 Cu 2+ is 3.60% (n = 6). The method is free from most of the interferences and the effect of diverse ions on the determination of Cu 2+ is also reported. The proposed method is virtually specific to copper and has been satisfactorily applied to its determination in electric copper wire samples and pharmaceutical products. Results were also verified by the atomic absorption spectrometry technique (AAS).

Determination of trace amounts of Cu(II) in drinking and wastewater samples by a novel catalytic kinetic spectrophotometric method

“…The current method is simple and fast, and can be used to determine copper at low levels. The proposed method has the advantages of low cost, a linear range of 30 fold, reproducibility, accuracy and, most importantly, low DLs, comparable with the DLs obtained by the existing catalytic kinetic techniques for the determination of trace quantities of Cu(II) present in water samples [38][39][40][41][42][43][44][45][46][47][48][49] in Table 4. Also, it has a lower reaction temperature and time than the other kinetic methods.…”

Kinetic-spectrophotometric method for the determination of trace amounts of bromide in seawater

“…There were only a few reports on the application of MB to the catalytic analysis of some elements [21,22].…”

Kinetic Analysis of Cobalt in Veterinary Products

“…[1][2][3][4] In the various real and artificial samples these methods are widely applied for the determination of trace metals. [5][6][7] Kinetic based techniques form an important part of the collection of methods available to the analytical chemist. 8 Many methods have been proposed for the determination of cobalt.…”