A sensitive spectrophotometric method for the determination of arsenic in environmental samples

Abstract

We developed a cost-effective and sensitive spectrophotometric method for the determination of arsenic at trace level using a new reagent, leuco malachite green. Here we show that, arsenic reacts with potassium iodate in acidic conditions to liberate iodine, and the liberated iodine selectively oxidizes leuco malachite green to malachite green dye. We studied the Beer's law at 617 nm, which showed linearity over the concentration range 0.09-0.9 lg ml -1 of arsenic. We show that the molar absorptivity, Sandell's sensitivity and detection limit of the method are 6.1 · 10 4 l mol -1 cm -1 , 0.0012 lg cm -2 and 0.025 lg ml -1 , respectively. We applied the developed method for the determination of arsenic in environmental samples.

Optimization of a Flow Injection System with Amperometric Detection for Arsenic Determination

“…The speciation of arsenic is mostly based on the determination of total arsenic after As(V) prereduction and determination of As(III) alone. Some of the methods used are flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS), [1][2][3] HG-AAS, [4][5][6] sequential injection hydride generation atomic fluorescence spectrometry (SIA-HG-AFS), 7 flow injection inductively coupled mass spectrometry (FI-ICP-MS), 8,9 electrochemical methods, [10][11][12] pervaporation-flow injection determination with photometric detection, 13 spectrophotometrical, [14][15][16] colorimetric 17,18 and FIA with chemiluminiscence detection. 19 Most methods are based on a hydride generation in an acidic media; according to the detection methods, they vary in the detection limits, as well as solution and sample consumption and the expense of the analysis itself.…”

New System for the Spectrophotometric Determination of Arsenic in Water

“…Many diseases such as gastrointestinal damage, skin and internal cancers, cardiac damage and vascular disorders are attributed to arsenic contaminant [5].The chronic arsenic poisoning has become a serious public health problem [6,7].Water pollution is an important means of arsenic contamination. The maximum permissible limit for arsenic in drinking water is 0.05 mg l -1 as recommended by WHO [1].In China, the limits are 0.01 mg l -1 in drinking water and 0.05-0.1 mg l -1 in the different levels of ground water respectively [8,9] Various analytical technique are used to determine arsenic, such as AFS, AAS, ICP(MS), XRF, NAA and spectrophotometry [10][11][12][13][14][15]. most of which require expensive experimental instruments , high running cost, professional operator, long time and complex sample treatment procedures prior to determination.…”

“…INTRODUCTION Arsenic (As) is a well-known toxic element and occurs naturally in the Earth's crust in its inorganic forms, trivalent (arsenite) or pentavalent (arsenate) [1]. In the same time arsenic is widely used in argriculture as well as in industry as pesticides, herbicides and the materials of glass manufacture, pigment production.…”

“…[16][17][18][19] At present, spectrophotometry has been used to test arsenic, using toluidine blue or safranine O, leuco malachite green, methyl orange, etc. [20][21][22]. In China, silver salt and arsenic-spot methods are the primary methods which also act as state standard methods [23,24].…”

The development and application of hybrid sorbents for determination and selective removal of arsenic(III) and arsenic(V) from water

“…These methods are based on conversion of arsenic to the colored compound [24][25][26][27][28][29][30] such as molybdenum blue [31][32][33], or silver diethyldithiocarbamate [34][35][36]. While some study based on the reaction of As(III) with potassium iodate in acid medium to liberate iodine, which oxidizes variamine blue to form a violet coloured species [37].…”