Rapid on-line solid phase enrichment using polytetrafluoroethylene beads for chromium speciation in contaminated real water samples

Abstract

Due to unchecked disposal of industrial wastes into surrounding areas, the pollution of water bodies with heavy metal toxicants has become an environmental menace. The toxicity of chromium species depends on its oxidation states, and thus regular monitoring of environmental water sources vulnerable to pollution is a must. In this regard, an on-line method for chromium speciation and determination using FAAS has been proposed. The flowinjection preconcentration mini-column containing polytetrafluoroethylene beads was used as the solid phase extractant, and chromium speciation was done by complexing Cr(III) and Cr(VI) with thiosemicarbazide chelating agent. The figures of merit for Cr(III) and Cr(VI) obtained were 61 and 56 (preconcentration factors); 0.13 and 0.14 lg L -1 (detection limits); 1.6 and 1.3% (R.S.D.). The optimized method for chromium speciation was successfully applied to industrial and Yamuna River water samples. The method validation was carried out using SRM 1640a (Trace Elements in Natural Water, NIST), and recovery [ 95% was obtained.

Determination of ultra-trace level Cr(vi) in seawater using large-volume direct injection by LC-ICP-MS with in-line matrix elimination

“…The collection and preparation of seawater samples were performed using the previously described method with some modifications. 10 The seawater samples collected were stored in pre-cleaned polypropylene bottles and were acidified prior to storage at a temperature of below 4 °C. Before the analysis of Cr speciation, the samples were adjusted to pH = 7.0 with dilute ammonia or dilute nitric acid and filtered through 0.22 μm cellulose acetate membrane.…”

“…In contrast, Cr(VI) is highly toxic, mutagenic and carcinogenic. [5][6][7][8][9][10] What's worse, Cr(VI) is highly water-soluble and mobile, leading to widespread water contamination over a long period. For this reason, Cr(VI) has been declared as a toxic hazardous pollutant and a class I human carcinogen by the United States Environmental Protection Agency (USEPA) and the International Agency for Research on Cancer (IARC), respectively.…”

Atomic spectrometry update: review of advances in elemental speciation

“…A SPE method in which both species were retained sequentially on the same (commercially available) adsorbent has been reported. 102 Both species were complexed with thiosemicarbazide (0.3 mol L À1 ); but at pH 1 only Cr III was retained on the column (30 Â 3 mm, glass) of PTFE beads, whereas at pH 7.0 only Cr VI was retained. Samples were handled with a commercial FI system coupled to a FAA spectrometer with an air-acetylene ame.…”

A Novel Glass Fiber Coated with Sol–Gel Poly-Diphenylsiloxane Sorbent for the On-Line Determination of Toxic Metals Using Flow Injection Column Preconcentration Platform Coupled with Flame Atomic Absorption Spectrometry

“…The analytical performance data of the proposed method together with that of other on-line solid phase extraction methods for lead and chromium(VI) determination with FAAS, reported in the recent literature [16,17,[24][25][26][27][28][29][30][31][32][33][34][35], are given in Table 3. The developed method features satisfactory sensitivity and precision (relative standard deviations, or RSD) with better detection limits (except [24]) and similar precision (RSD) for the lead determination.…”