A new reagent system for the highly sensitive spectrophotometric determination of selenium

Abstract

Highly sensitive and simple spectrophotometric determination of selenium is described for the determination of selenium(IV) using a new reagent leuco malachite green. The method is based on the reaction of selenium(IV) with potassium iodide in an acidic condition to liberate iodine, the liberated iodine oxidizes leuco malachite green to malachite green dye. The green coloration was developed in an acetate buffer (pH 4.2–4.9) on heating in a water bath (∼ 40 °C). The formed dye exhibits an absorption maximum at 615 nm. The method obeys Beer’s law over a concentration range of 0.04–0.4 µg mL−1 selenium. The molar absorptivity and Sandell’s sensitivity of the color system were found to be 1.67 × 105 L mol−1 cm-1 and 0.5 ng cm−2, respectively. The optimum reaction conditions and other analytical parameters have been evaluated. The proposed procedure has been successfully applied to the determination of selenium in real samples of water, soil, plant material, human hair, and cosmetic samples. The results were compared to those obtained with the reference method. Statistical analysis of the results confirms the precision and accuracy of the proposed method. In addition, the developed method is cost-effective and involves easily accessible instrumentation technique which can be used by ordinary research laboratories.

Effects of dietary organic selenium on immune responses, total selenium accumulation and digestive system health of marron,Cherax cainii(Austin, 2002)

“…The sampled marron from each tank culture were killed to determine the total soluble Se in haemolymph, hepatopancreas and muscle tissues. Total soluble Se was determined using a spectrophotometric method according to Revanasiddappa and Dayananda (). Briefly, 4 mL concentrated HNO 3 was added to all samples and heated at 80°C for 1 h, then another 3 mL HNO 3 was added to the solution.…”

Multi-pumping mechanised determination of selenium in natural waters by light emitting diode (LED) spectrometry

“…The proposed method provides a limit of detection of the same order than that obtained by using NPDPTC after a previous separation of the gas phase generation, 9 and clearly lower than other photometric procedures. 3,7,8 It seems that kinetic spectrophotometric approaches provide an enhancement of the LOD and astonishing the sensitivity reported for FIA spectrophotometric determination with MBTH is one order of magnitude better than that obtained by us. However, on looking through the aforementioned study, 12 it can be seen that authors reported a sensitivity of 0.1875 for the concentration range between 0.050 and 0.500 mg L -1 which is clearly lower than the value of 0.501 obtained in this study for the range between 0.010 and 0.500 mg L -1 and thus it is surprising that they could found a LOD of 0.00025 mg L -1 nor for using a 2σ criterion.…”

“…1,2 In terms of sources of selenium in the environment it can be noticed volcanic eruption, insecticides, fertilizers, smelting ceramic, metallurgical operation, glass rubber accelerators, paints, dyes and electronic goods, 3 additionally there are some industrial and agricultural processes which can cause the presence of Se in natural waters, 4 According to the sanitary and hygiene standards, 0.05 mg L -1 is the maximum permissible concentration of Se in water, 5 and 0.1-0.2 mg dm -3 the Threshold Limit Value (TLV) for selenium compounds in air. 6 Spectrophotometric methods reported in the literature for the determination of Se in water are based on the batch reaction of Se with potassium iodide in an acidic medium to liberate iodine, which oxidizes leuco malachite green, 3 or Variamine Blue 7 to produce a coloured product; oxidation of p-nitroaniline by selenium (IV) followed by reaction with N-(1-naphthalene-1-yl)ethane-1,2-diamine dihydrochloride (NEDA) 8 or previous gas extraction of Se followed by reaction with and 2-(p-nitrophenyl)-3,5-diphenyltetrazolium chloride. 9 Kinetic spectrophotometric methods have been also reported based on the reduction of trisodium 4,5-dihidroxi-3-[(p-sulfophenyl)]-2,7-naphtalenedisulfonic acid by sulphide in Vol.…”

Spectrophotometric Determination of Selenium (IV) Using 4,5-diamino-o-xylene as a New Chromogenic Reagent

“…Moreover these methods have many individual limitations like use of sophisticated instruments, time consuming operation, requires multi-step procedures for pre-concentration of analyte and low selectivity with higher interference problems. In addition to the above-mentioned methods, studies on molecular spectroscopy-based articles show some drawbacks such as having low molecular absorption coefficients in the ultraviolet region, lack of any report about cationic interferences studies, and in some cases the reported detection limits are not competitive with the results of atomic spectroscopic techniques [20][21][22][23][24][25][26][27][28][29][30].…”