Determination of Trace Amount of Carbon Disulfide in Water by the Spectrophotometric Reaction-Rate Method

Abstract

The most widely used procedures for determining dithiocarbamate and tetramethylthiuram disulfide fungicide residues involve a spectrophotometric determination of CS2 after hot acid digestion of the sample. Accurate measurements of the ambient carbon disulfide concentration in industrial waste water and in an industrial atmosphere are necessary to protect the health of workers. Among the deleterious effects of chronic CS2 intoxication are vitamin B6 deficiency, depletion of the levels of essential trace metals, such as Cu and Zn, and an intensification of the development of atherosclerosis. 1,2 It is, therefore, of interest to develop a simple and rapid method for the determination of this pollutant. Different methods have been used for the determination of carbon disulfide in water, including spectrophotometry, 3-6 chromatography, 6-8 GC-flame photometric, 9 and -mass spectrophotometric 10 methods. Of these methods, spectrophotometric methods have been shown to be more simple than the other methods. The most widely used procedure for determining CS2 by spectrophotometry is the adsorption of CS2 in a copper-diethanolamine reagent, that yields a yellow complex.3 This method cannot quantify the CS2 concentration below 2 µg/ml. 6 The other spectrophotometric methods 4-6 have a high limit of detection, a short linear dynamic range and are time consuming.To our knowledge, there has not been any report concerning the kinetic-spectrophotometric method for the determination of trace amounts of CS2. The proposed method is described as a kinetic method based on an induction effect of CS2 on the oxidation of sodium azide by triiodide that is monitored spectrophotometrically. Experimental Reagents and chemicalsAll of chemicals used were of analytical-reagent grade and doubly distilled water was used.Carbon disulfide (100 µg/ml) was prepared by adding 0.108 ml CS2 (Merck) to water in a volumetric flask.A triiodide stock solution (1.0 mM) was prepared by adding 0.0254 g of I2 to 0.45 g of KI and dissolved in 100 ml of water in a volumetric flask. The resulting solution was standardized by sodium thiosulfate method.A stock solution of 2.50 M sodium azide solution was prepared by dissolving 25.5 g of NaN3 (Merck) in water and diluting in a 100-ml volumetric flask. ApparatusA UV-VIS Spectronic 20 (Genesys) with a 1.0 cm glass cuvette was used to measure the absorbance at 350 nm. A thermostat (Gallen Kamp Griffin, BJ-240 V) was used to keep the reaction temperature at 30˚C.A column (10 × 5 mm) containing 1.0 g of active carbon was used in the separation of CS2 from sample solutions by passing a 1000 ml solution containing of CS2 plus other cations through the column at a flow rate of 100 ml/h. The column was then washed with 10 ml of a mixture of (50:50) isoamyl acetate/ethanol at a flow rate of 50 ml/h. ProcedureAll of the solutions were preheated to the working temperature (30˚C) in a thermostat water bath for 30 min before initiating the experiment.The reaction was followed spectrophotometrically by monitoring the decrease in t...

Kinetic Insights into Hydrogen Sulfide Delivery from Caged-Carbonyl Sulfide Isomeric Donor Platforms

“…To rule out the possibility that released CS 2 was reacting with H 2 O 2 to produce H 2 S, we incubated authentic CS 2 sample directly with H 2 O 2 under identical conditions but failed to observe H 2 S release (Figure S4). Our attempts to measure CS 2 released from the PeroxyDTCM donors using different CS 2 -responsive colorimetric methods − as well as by GC have remained unsuccessful, suggesting that CS 2 release is not facile from these compounds. This lack of CS 2 release could be due, in part, to the greater stability of the dithiocarbamate anion formed after the initial self-immolative decay by comparison to the corresponding anionic thiocarbamate anions.…”

One-Pot Catalytic Cleavage of C═S Double Bonds by Pd Catalysts at Room Temperature

“…Catalytic activation of carbon sulfur bond is important due to its wide applications in chemical, − energy, and environmental industry. , Hydrodesulfurization (HDS), the conversion of organic sulfur compounds to hydrogen sulfide and hydrocarbons by catalytic technologies, is one of the most important steps in petroleum refining industry, since fossil fuel usually contain organic sulfur impurities. , Furthermore, conversion of hazardous sulfur compounds to harmless chemicals is critical for environmental protection. In general, industrial-scale sulfur removal is carried out through heterogeneous catalysis, , while the mechanisms are still under investigation. , Thus, many efforts have been dedicated to the carbon–sulfur bond activation with transition metal complexes to probe the mechanism for developing highly efficient industrial catalysts. , Different transition metals have been employed to mediate the C–S bond activation, including palladium, − platinum, , rhodium, − iridium, , copper, , nickel, , iron, , cobalt, , ruthenium, , tungsten, and niobium, , among others.…”

Spectrophotometric Determination of Carbon Disulphide in the Workplace Air

“…Reactions with thiols were used for spectrophotometry determination of CS 2 , for instance, benzyl thiol, which in the presence of potassium hydroxide reacts on yellow potassium benzyl-trithiocarbonate [11]. Spectrophotometric kinetic iodide-azide method was also used for the sensitive determination of carbon disulphide [12]. Indirect determination of CS 2 with reagent of bis[4(4 � -nitrophenyl)azo-2nitrophenyl] disulphide is also known [13].…”