The effect of experimental conditions on the formation of dixanthogen by triiodide oxidation in the determination of ethyl xanthate by HPLC–ICP-MS/MS

Abstract

The rising concern over the environmental impact of xanthates, especially in the arctic region, has increased the need to study these traditional flotation reagents in greater detail. The environmental concern relates mostly to the formation of carbon disulfide (CS2) and the heavy metal complexes of xanthates. Due to the unstable nature and multiple reaction mechanisms of xanthates, their reliable determination at low concentration levels is difficult. In this study, a xanthate pretreatment method was optimized and applied for the determination of ethyl xanthate (EX−) by high performance liquid chromatography–inductively coupled plasma tandem mass spectrometry (HPLC–ICP-MS/MS). Ethyl xanthate was oxidized to diethyl dixanthogen ((EX)2) by triiodide (I3−) in aqueous solution and the formed (EX)2 was extracted into n-hexane. Important experimental parameters, including pH, I3− amount, and oxidation time, were optimized and the detection limit of 0.29 mg L−1 for potassium ethyl xanthate was obtained. During the optimization experiments, it was found that the oxidation reaction resulted in multiple products, decreasing the efficiency of (EX)2 formation and, therefore, the sensitivity of the method. The proposed method was applied to wastewater samples with recoveries of 105–106%. This study provides a selective method for the determination of ethyl xanthate and introduces novel information on the parameters affecting the oxidation of xanthates. Graphical abstract

Determination of xanthates as Cu(II) complexes by high‐performance liquid chromatography – Inductively coupled plasma tandem mass spectrometry

“…The obtained method's detection limits of 13.3 and 24.7 μg/L for the determination of SIBX and SIPX, respectively, are comparable to other selective methods for the determination of xanthates. The previous method of applying triiodide oxidation and HPLC‐ICP‐MS/MS determination resulted in an instrumental detection limit [19] of 20 μg/L and a method detection limit [20] of 0.29 mg/L. Similar detection limits have been achieved with other selective methods, namely CE (10 μg/L) [16], anion interaction chromatography (30 μg/L) [31], SPE‐HPLC‐MS/MS (0.06−0.24 μg/L) [17] and ion‐pair chromatography (4 μg/L) [14].…”

“…Few other selective methods, such as applying CE [16] and HPLC-MS/MS with SPE as a pretreatment step [17], have been developed to determine xanthates. Xanthates have also been measured by HPLC as dixanthogens after oxidation using a UV detector [15,18] or, more recently, inductively coupled plasma MS/MS (ICP-MS/MS) [19,20].…”

Review: Sulfur Analysis using Inductively Coupled Plasma Mass Spectrometry

“…Notably, most articles reported detection limits < 6 ng/g, except for some that were hyphenated with CE, UPLC, HPLC, and LC. 60,64,82,86,98 The detection limits obtained by HR-ICP-MS were 0.09-500 ng/g, except for some hyphenated with LA, which reported a detection limit > 10000 ng/g. 9,37 These high detection limits by LA-HR-ICP-MS can be attributed to the analysis of sulfur in large molecules by introducing an extremely small quantity (~30 ng/s) of the sample.…”

“…17,31 HPLC-ICP-QMS/QMS was used to analyze sulfur species such as proteins, peptides, thiocyanate, xanthates, and amyloid-β. 13,31,82,98,108 HPLC-HR-ICP-MS was used to analyze sulfur species such as metabolites in mice urine, phosphopeptides, methionine, amyloid-β, and hemoglobin. 16,17,21,69,96 HPLC-MC-ICP-MS was used to analyze metabolites in mice urine and methionine in human blood plasma.…”

Development of Novel Analytical Methods Based on Liquid Chromatography and Electrophoresis

“…Although their origins are sufficiently old, the development of novel separation methods based on HPLC and electrophoresis are maintained. Both fundamental and applicational studies are still progressing to analyze a wide variety of compounds [1][2][3][4][5][6][7][8][9][10][11][12].…”