Separation and detection of low concentrations of polythionates by high speed anion exchange liquid chromatography

Abstract

but the LC water/methanol gradient technique did not separate the parent compound from the major metabolic product, hydroxy-naphthalene. Both compounds were, however, readily identified in the mass spectra corresponding to a single LC peak. Furthermore, an LC/MS combination obviates the need for the high purity, optically transparent solvents used with UV-detection systems. The use of the membrane device, however, limits the solvents to readily volatile, polar compounds.An LC/MS interface can be, therefore, of great utility for the identification of compounds in the LC effluent, even though the physical requirements of the MS limit the general applicability. Important considerations in the selection of an LC/MS interface include: 1) the volatility of the compounds of interest in relation to the operating temperature of the interface; 2) the solvent rejection of the device with respect to the LC flow rate and MS pumping speed; and 3) the minimum quantities of material available for detection.

Physicochemical Fate of Sulfate in Soils

“…Concentrations of S2O3 2~ in tailing pond effluents have been estimated to be in the range of 500 mg/L. 8 Although the chemical nature of organic S in soils has been under investigation for the past three decades, little is known about the organic S compounds present in soils. Early work showed the presence in soils of organic S compounds such as trithiobenzaldehyde, 9 and free cystine.…”

Effect of Ethanol Addition on the Determination of Thiosulfate Based on Reduction of Ce(IV) and Fluorescence Detection of Ce(III)

“…In the absence of alcohol, thiosulfate could be determined at levels as low as 10 -6 M. This is because thiosulfate reduces Ce(IV) to Ce(III), 14,16 as shown in Eq. (1), and the detection limit for Ce(III) is around 10 -6 M. The detection limit for thiosulfate under these conditions was calculated as 3.0 × 10 -7 M (S/N = 3).…”

“…Several sensitive and selective detection methods have utilized a postcolumn reaction of thiosulfate with Ce(IV), followed by fluorescence detection of the resulting Ce(III). [16][17][18][19] Ce(IV) is susceptible to reduction by reducing agents to form Ce(III), and measurement of the resulting Ce(III) can allow the determination of the reducing agent. Ce(III) has a characteristic fluorescence with an excitation maximum at 260 nm and an emission maximum at 350 nm, while Ce(IV) does not fluoresce.…”

“…This postcolumn reaction has been applied to the IC detection of thiosulfate, polythionates, nitrite, thiosulfate and iodide. 16,17 Miura et al 18 reported that Ce(IV) can be converted into Ce(III) by L-ascorbic acid, sulfite, oxalate and thiosulfate in an acidic medium. In these reports, the detection limits for thiosulfate were in the range of 10 -7 -10 -6 M. While studying the determination of thiosulfate by fluorescence detection of Ce(III), we found that the sensitivity of thiosulfate detection was increased by the addition of a thiosulfate solution into a mixture of Ce(IV) and alcohol solution, particularly when ethanol was used, compared with a Ce(IV) solution containing no alcohol.…”

Highly sensitive chemiluminescence determination of tenoxicam using a cerium(IV)–sodium hyposulphite system in micellar medium

“…It was observed that fluorescence spectra for cerium(III) and TX were obtained at 365 nm and 450 nm, respectively. Cerium(IV) is non‐fluorescencent . When TX mixed with cerium(III) in HNO 3 , the fluorescence emission showed a broad peak at 367 nm and a very weak peak at 456 nm.…”