Adsorptive Voltammetric Stripping Analysis of Ultra-Trace Amounts of Tin in Natural Waters and Sediments

Abstract

-A voltammetric method based on the adsorption of tin(IV)-catechol complex on a hanging mercury drop electrode is described for the determination of ultra-trace amounts of tin in environmental samples. The interfacial accumulation of the analyte and the use of differential pulse voltammetry during the reduction step provide substantial gains in the sensitivity and permit selective determination of tin in the presence of other elements. Optimal conditions for this method are pH 4.2,1 x 10~M catechol, and accumulation with stirring at 0.0V versus Ag/AgCI. The detection limit based on the use of the tin peak which occurred at -0.3V versus Ag/AgCI was 5ng/L for an accumulation period of 180s and the relative standard deviation at 50ng/L was 2.2%. The successful application of the method to tin determination in water and sediment samples is reported. Keywords -tin, catechol, adsorptive voltammetry, natural waters, sedimentsTin is one of the few elements that are known to be essential at trace levels to man, animals, and plants for a range of metabolic processes [1,2]. However concern about its toxicity has been growing in recent times owing to its widespread use in various organic forms for wood preservation, in food packaging, as stabiliser for poly(vinyl chloride), as fungicides or pesticides, as catalysts, in veterinary formulations, and as antifouling agents [3,4]. As viable antifouling agents, the organotin compounds function by releasing poisonous chemicals to the marine organisms at a slow but steady rate, thereby preventing their attachment to the ship's hull. The released organotin compounds may be ultimately degraded by the progressive removal of the organic groups as follows [4] :R4Sn ---. R3SnX -r--. R2SnX2 --. RSnX3 -.SnX4 where X = C1-,1-, Br-, etc.Although the amount of the organotin released to the marine environment by the use of antifouling coatings may seem insignificant, their growing use may result in more serious environmental and toxicological problems. Consequently, this has led to the development of numerous analytical methods for the determination of tin in various environmental materials. Among these are various electroanalytical techniques such as do polarography, ac polarography, differential pulse polarography, and variants of anodic stripping voltammetry. Of these, the anodic stripping voltammetric techniques are suited for the determination of trace amounts of tin because of the added preconcentration of the analyze on the working electrode.A major difficulty in the determination of tin by anodic stripping voltammetry and polarography is caused by the interference of lead, which often results in an overlap of the tin response [5][6][7][8][9][10]. The perfect superimposition of the lead response on that of tin in most electrolytes is generally known to result in serious positive errors. Several schemes have therefore been proposed for overcoming the lead interference in the anodic stripping voltammetric or polarographic determination of tin. Most of these schemes are somewhat c...

Stripping Voltammetry with Nanomaterials‐based Electrode in the Environmental Analysis of Trace Concentrations of Tin

“…Several voltammetric methods can be used for the determination of tin, such as anodic stripping voltammetry (ASV), [18][19][20][21][22][23][24][25][26][27][28] cathodic stripping voltammetry (CSV) [29] and adsorptive stripping voltammetry (AdSV). [30][31][32][33][34][35][36][37][38] In the voltammetric methods, different working electrodes have been used during the experiments performed. The most common working electrodes have been hanging drop mercury electrode, [18][19][20][30][31][32][34][35][36][37] glassy carbon mercury film electrode (GCMFE), [33] carbon paste electrode (CPE), [21] bismuth film electrode (BiFE), [22][23][24][25][26] solid bismuth microelectrode (BiFμE), [38] bismuth/poly (bromophenol blue) modified glassy carbon electrode (Bi/poly(BPB)GCE) [27] and chemically modified electrode (CME).…”

2,2-Hydroxyphenylbenzoxazole as a selective chelating agent for complexation with Tin and Zinc: a voltammetry study

“…Electrochemical methods have shown numerous advantages including speed of analysis, good selectivity and sensitivity, good performance with saline matrixes like river water and the possibility of simultaneous analysis of mixtures [15,31]. At this time, a few organic compounds such as Morin [6], mixture of dimethylglyoxim and oxine [7], cupferron [8], catechol [16], tropolone [17,18], chloranilic acid [19], propyl gallate [20], phenylfluorone [21] and 8-hydroxyquinoline [22] as complexing agent have been reported for the determination of zinc and tin ions at ultra-trace level. In this paper, a novel adsorptive stripping voltammetry method is reported for the simultaneous quantification of tin and zinc.…”

Determination of Trace Tin by Anodic Stripping Voltammetry at a Carbon Paste Electrode

“…This technique is based on adsorptive accumulation of a complex of the element with an added specific ligand on an electrode surface followed by electrochemical reduction of either the element or the ligand in the complex. The trace determination of tin by adsorptive stripping voltammetry at a hanging mercury drop electrode (HMDE) in the presence of catechol [2], tropolone [3,4], chloranilic acid [5], propyl gallate [6], phenylfluorone [7] and 8-hydroxyquinoline [8] was reported. Although the sensitivities of these methods at a HMDE are fairly high, the mercury is becoming rather controversial material.…”