Extraction, preconcentration and spectrophotometric determination of trace levels of thiosulfate in environmental waters

Abstract

are statistically in a good agreement with those obtained by DTNB method. Finally, the method developed was successfully applied to the preconcentration and determination of trace thiosulfate from environmental waters. Abstract In the existing study, a new vortex-assisted cloud point extraction (VA-CPE) method was developed for determination of low levels of thiosulfate in environmental waters at 632 nm by spectrophotometry. The method is selectively based on charge-transfer-sensitive ion-pair complex formation of Ag(S 2 O 3 ) 2 3− , which is produced by the reaction of thiosulfate with excess Ag + ions with toluidine blue (3-amino-7-dimethylamino-2-methylphenazathionium chloride, TB + ) and then its extraction into micellar phase of polyethylene glycol 4-tert-octylphenyl ether (Triton X-45) in presence of Na 2 SO 4 as salting-out agent at pH 7.0. All the factors affecting complex formation and VA-CPE efficiency were optimized in detail. Under the optimized conditions, the linear calibration curves for thiosulfate were in the range of 0.2-120 and 5-180 µg L −1 with sensitivity improvement of 81-folds and 15-folds, respectively, as a result of efficient mass transfer obtained by CPE with and without vortex, while it changed in the range of 260-3600 µg L −1 without preconcentration at 642 nm. The limits of detection and quantification of the method for VA-CPE were found to be 0.05 and 0.22 µg L −1 , respectively. The precision (expressed as the percent relative standard deviation) was in range of 2.5-4.8% (5, 10 and 25 µg L −1 , n: 5). The method accuracy was validated by comparing the results to those of an independent 5,5′-dithiobis(2-aminobenzoic acid) (DTNB) method as well as recovery studies from spiked samples. It has been observed that the results * Ramazan Gürkan Keywords

Preconcentration of sulfite from food and beverage matrices by ultrasonic assisted-cloud point extraction prior to its indirect determination by flame atomic absorption spectrometry

“…DPTZ is a selective Fe(II) binding reagent, and its metal complexes are easily soluble in water. 22,23 Because of high water solubility, the cationic Fe(DPTZ) 2 2+ complex can't quantitatively be extracted into surfactant rich phase. To determine minimum detectable levels of sulte in a wide working range, the UA-CPE has been explored using anionic surfactant, SDS as ion-pairing agent with opposite charge.…”

Fast Determination of the Main Reduced Sulfur Species in Aquatic Systems by a Direct and Second-Derivative Spectrophotometric Method

“…e other species, called intermediate sulfur species, generally represent a very small fraction (<0.01%) of the total dissolved sulfur content [12]. Nevertheless, several studies realized in brines, volcanic lakes, and hydrothermal systems have found relative proportions of thiosulfates and polythionates, which could reach 20% of the total dissolved sulfur content [12,13]. Sulfites (HSO 3 − and SO 3 microbial metabolisms, their monitoring is frequently required to assess the nature and level of activities of anaerobic ecosystems in fundamental or applied research.…”

A facile “off–on” pattern based on one-pot synthesis of N-doped carbon dots for sensitive detection of Ag+and S2O32−

“…The determination of thiosulfate is very important in many environmental and industrial situations, especially in the process of monitoring anoxic water and wastewaters from paper mills and photographic laboratories. 7 Furthermore, thiosulfate in blood and urine is used as a reliable indicator for the identification of sulfur poisoning. 8 Thus, the detection of thiosulfate anions (S 2 O 3 2− ) in water and physiological fluids is of great importance.…”

“…So far, a variety of methods have been developed to detect Ag + and S 2 O 3 2À including fluorescence analysis, colorimetry analysis, electrochemical methods, UV-vis spectrophotometry, etc. 7,[9][10][11][12][13][14][15][16] Fluorescence detection has proved to be an effective method due to its intrinsic advantages of high sensitivity, low cost, operation simplicity and rapid response. A variety of materials have been developed for fluorescence detection, such as semi-conductor quantum dots, organic fluorescent dyes, MOFs, Au/Ag nanoclusters and carbon-based nanoparticles.…”