[The optimization of 2-thiothiazolidine-4-carboxylic acid back extraction in urine and determination by HPLC]

OBJECTIVE

Establishment of determination method of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine with HPLC.

METHODS

A volume of 0.5 ml hydrochloric acid (2 mol/L) and 0.5 ml pure water was added into 1 ml urine, and then extracted by 4 ml of diethyl ether by shaking for 2 min. Remove the water phase in a tube with plug and extract again, mix the two extraction diethyl ether together, take 4 ml by adding 2 ml borax-monopotassium phosphate buffer and shaking for 2 min to extract, then take the water phase to detect. A C(18) column and UV detector were used for separating and detecting. The wavelength was 273 nm, the flow rate was 1.0 ml/min, and the injection volume was 20 µl.

RESULTS

TTCA has a good linearity (r = 0.9995) over the concentration of1 1 ∼ 10 µg and the minimum detectable concentration of TTCA in urine was 0.1 µg/ml. The within-day precision (RSD) were 8.4%, 3.0% and 1.7%, the between-day precision (RSD) were 11%, 3.8%, 1.9%, respectively. The extraction recovery were between 80% ∼ 102%.

CONCLUSION

The method was accurate and sensitive to detect TTCA in urine.

Immunomodulatory effects of occupational exposure to mancozeb

The effects of occupational exposure to ethylene-bis-dithiocarbamate of manganese and zinc on the immune system were evaluated in a group of mancozeb-exposed manufacturers and controls. The immune system tests revealed the following: (a) lymphocyte proliferative responses triggered by different activators and mitogen-induced IL-2 production were higher in exposed subjects than in controls; (b) production of monocyte/macrophage-derived IL-1 and polyclonal IgG and IgM, by beta-lymphocytes, did not differ between exposed subjects and controls; (c) percentages and absolute numbers of total T-cells, T-helper cells, T-suppressor/cytotoxic cells, activated T-cells, total beta-cells, and natural killer cells were similar in exposed subjects and controls; (d) serum immunoglobulin classes and complement fractions were within the range of normality; and (e) rheumatoid factor and non-organ-specific serum autoantibodies were absent in exposed and control subjects. An increase in T-cell functional response was found in the exposed group, suggesting a slight immunomodulator effect of mancozeb in conditions of low-level, prolonged occupational exposure.

Blood and urine concentrations of chemical pollutants in the general population

The concentration of 9 environmental chemical pollutants in the general population was measured in blood and urine. For the 9 different pollutants, the blood samples tested varied from 88 for acetone to 431 for benzene. Urine samples varied from 48 for styrene to 213 for n-hexane. Six of these agents (benzene, toluene, styrene, n-hexane, acetone and carbon disulphide) were present in all or almost all (100-94%) blood samples. The three chlorides (chloroform, trichloroethylene and tetrachloroethylene) were present only in 60-85% of samples. After acetone, with blood concentrations in microgram/1 (mean 840 microgram/l), the highest mean blood levels were those of toluene (1097 ng/l), chloroform (955 ng/l) and n-hexane (642 ng/l). Trichloroethylene and free carbon disulphide showed similar values (458 and 438 ng/l, respectively). Finally, benzene, styrene and tetrachloroethylene showed the lowest values (262, 217 and 149 ng/l, respectively). There was generally a significant difference between rural and urban workers in terms of blood benzene (200 ng/l vs 264 ng/l), trichloroethylene (180 ng/l vs 763 ng/l) and tetrachloroethylene (62 ng/l vs 263 ng/l). In a group of subjects potentially exposed to industrial solvents, classed as chemical workers, blood benzene, toluene, chloroform and n-hexane were significantly higher than in rural and urban workers. Smokers showed a significantly higher blood concentration than non-smokers for benzene (381 ng/l vs 205 ng/1), toluene (1431 ng/l vs 977 ng/l), and n-hexane (838 ng/l vs 532 ng/l). All or almost all urine samples (100-92%) contained all the compounds except trichloroethylene and tetrachloroethylene, present in 79% and 76% of samples, respectively (table 2). Urinary concentrations of all compounds did not differ significantly between rural and urban workers. Benzene and toluene were significantly higher in in urine of smokers than of non-smokers. Chloroform and n-hexane showed significantly higher urinary than blood values. Excluding acetone, with urinary and blood concentrations in pg/l, chloroform, toluene and n-hexane showed the highest mean concentrations both in blood and in urine.

[Carbon disulfide excretion in urine--a biological exposure test for the workplace and environmental concentration ranges]

The biological control procedure for carbon disulphide (CS2), the determination of free and bound CS2 in urine--a procedure already applied to hygienic surveillance--were modified by using gas chromatography and sulphide selective detection (FPD). The results obtained by the changed biological monitoring test in workplace and environmental surveillance are present and discussed. For CS2 concentrations at workplaces in the range of 8-54 mg/m3 a correlation coefficient of r = 0.56 (n = 11, p less than 0.07) was calculated for the mathematical connection of CS2 shift exposure and CS2 content in urine. For environmental exposures in the range of the CS2 immision short term threshold value (MIKK) of 0.03 mg/m3 the procedure may discriminate significantly exposure load from naturally occurring CS2 background.

Determination of thio compounds in urine of workers exposed to carbon disulfide

Metabolites of carbon disulfide excreted into the urine of viscose workers are detectable by application of a nonselective assay for the determination of thio compounds. Enhanced secretion of thio compounds occurred especially at the end of the workday in exposed workers. A classification of urine samples according to the degree of exposure gave evidence for a relation between exposure to carbon disulfide and excretion of thio compounds in urine. The presence of 2-thiothiazolidine-4-carboxylic acid in urine of viscose workers was indicated by TLC, UV-spectrometry, and HPLC.

Determination of disulfiram and metabolites from biological fluids by high-performance liquid chromatography

A high-performance liquid chromatographic method is described for the determination of disulfiram, diethyldithiocarbamate, diethyldithiocarbamate methyl ester, carbon disulfide, and diethylamine from a single sample of plasma or urine. The analytical procedure is based on a quantitative stepwise extraction of disulfiram and diethyldithiocarbamate methyl ester, or the conversion of diethyldithiocarbamic acid, carbon disulfide and diethylamine to diethyldithiocarbamate methyl ester for chromatographical determination. The procedure is specific, precise and simple. The application of the analytical methods developed for the determination of disulfiram and the various metabolites in plasma from mice given disulfiram intraperitoneally or humans given Antabuse orally is illustrated.

Methods for detecting disulfiram in biologic fluids: application in studies of compliance and effect of divalent cations on bioavailability

Studies regarding the efficacy of disulfiram in the treatment of alcoholism have not included a method of evaluating compliance to the prescribed regimen. This article outlines current methods used to detect disulfiram in blood, breath, and urine.

Carbon disulfide. I. The metabolism of inhaled carbon disulfide in the rat

The pharmacokinetics of inhaled carbon disulfide (CS2) vapor was evaluated in rats. Estimates of free CS2 and its nonvolatile, acid-labile metabolites (AL CS2) were made in a variety of rat tissues after an 8-hour inhalation exposure to CS2 vapor (2 mg/l of air). At the end of the exposure, all tissues examined contained appreciable amounts of the native solvent and AL CS2. Elimination of CS2 from the rat during the postexposure period was rapid and occurred primarily via the lungs. Excretion of AL CL2 occurred primarily via the kidneys and was prolonged with respect to that of free CS2. Accumulation of these metabolites upon repeated exposures and their presence in all tissues examined suggest that they may play a role in the toxicity of CS2.