thiourea and propylenethiourea

A sensitive and specific method for the determination of propineb and its metabolites, propylenethiourea (PTU) and propylenediamine (PDA), using gas chromatography with flame photometric detection (GC-FPD) and LC-MS/MS was developed and validated. Propineb and its metabolite residue dynamics in supervised field trials under Good Agricultural Practice (GAP) conditions in banana and soil were studied. Recovery of propineb (as CS

Topics: Agriculture; Chromatography, Gas; Chromatography, Liquid; Diamines; Food Analysis; Food Contamination; Fungicides, Industrial; Half-Life; Limit of Detection; Musa; Pesticide Residues; Reproducibility of Results; Soil Pollutants; Tandem Mass Spectrometry; Thiourea; Zineb

In this work, a new method for the determination of ethylenethiourea (ETU) and propylenethiourea (PTU) in fruits and vegetables is presented. Different extraction and purification techniques, including matrix solid phase dispersion (MSPD) and solid-liquid extraction (SLE), followed by a clean-up step by solid phase extraction (SPE), were compared. The determination of ETU and PTU was performed by high performance liquid chromatography with diode array detection (HPLC/DAD) or by gas chromatography with mass spectrometry detection (GC/MS). The effect of several parameters on the extraction, separation and detection was studied. The proposed method based on solid-liquid extraction with acetonitrile, clean-up with Envicarb II/PSA cartridges and subsequent analysis by HPLC/DAD was characterised and applied to the analysis of fruits and vegetables from different countries. Analytes recoveries were between 71% and 94% with relative standard deviations (RSDs) ranging from 8% to 9.5%. Quantification limits obtained for ETU and PTU with the HPLC/DAD method were 7 and 16 μg kg⁻¹ in strawberries (fresh weight), respectively. For apples, they were 11 and 25 μg kg⁻¹, respectively.

Topics: Crops, Agricultural; Ethylenethiourea; Food Contamination; Food Inspection; Fragaria; Freeze Drying; Fruit; Fungicides, Industrial; Lactuca; Limit of Detection; Malus; Mediterranean Region; Particle Size; Pesticide Residues; Plant Extracts; Plant Leaves; Reproducibility of Results; Spain; Thiocarbamates; Thiourea; Vitis

Ethylenethiourea (ETU) and propylenethiourea (PTU) are the main degradation products of dithiocarbamates fungicides, which are widely used in agriculture from several years ago. Their determination in water at low concentrations (e.g. sub-ppb levels) is highly problematic due to their polar character and low molecular size. In the present study, two analytical methodologies have been developed and compared for the selective and sensitive determination of ETU and PTU in various types of waters. Both approaches are based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with electrospray ionization, using triple quadrupole analyzer. Whereas the first methodology used an on-line solid-phase extraction (SPE) step in order to reach the adequate sensitivity, the second one avoided sample treatment and was based on direct injection into an ultra high performance liquid chromatography (UHPLC-MS/MS) system, making use of a new-generation instrument in order to reach sub-ppb analyte levels in water. Strong matrix effects (typically leading to signal enhancement) were observed for most of the evaluated waters, especially when applying the on-line SPE method, surely due to the higher amount of sample injected into the system. The use of the own analyte (ETU-d₄)) as isotope-labelled internal standard (ILIS) allowed to compensate these effects and to achieve an accurate ETU quantification at low concentrations. Moreover, three simultaneous transitions, operating in selected reaction monitoring mode, were acquired for both ETU and ETU-d₄. This fact together with the evaluation of their relative intensity ratios assured the reliable identification of the analyte in the water samples. The two optimized methodologies were validated by analysis of six different samples (two drinking water, two groundwater and two surface water), spiked at two levels (0.1 and 1.0 μg/L), and analyzed each in quintuplicate. Satisfactory accuracy and precision, with recoveries ranging from 73 to 104% and RSDs lower than 20%, were obtained for ETU. Limits of detection for ETU were found to be 0.058 μg/L and 0.027 μg/L with direct injection and with the on-line methodology, respectively. No satisfactory recoveries were obtained, in general, for PTU despite using its own deuterium-labelled molecule for matrix effects correction. Notable differences in the chemical behaviour between PTU and PTU-d₆ were observed, which lead to significant variation in their chromatographic rete

Topics: Chromatography, High Pressure Liquid; Drinking Water; Ethylenethiourea; Fresh Water; Reproducibility of Results; Sensitivity and Specificity; Tandem Mass Spectrometry; Thiourea; Water Pollutants, Chemical

Previous published methods for the analysis of ETU and PTU are time-consuming and furthermore use dichloromethane (DCM) for extraction or clean-up. This study details the development and validation of a rapid method that combines a simple extraction step with UHPLC-ESI(+)-MS/MS. This is the first application of UHPLC-MS/MS to analyse these compounds. Besides that, we replaced DCM with a more environmental-friendly solvent. The analytical performance was evaluated with the analysis of spiked celery samples at 50 μg kg(-1) (LOQ) and 300 μg kg(-1). The recoveries were between 65% and 90% for ETU and between 71% and 127% for PTU with RSDs in repeatability and reproducibility conditions below 10% for ETU. This method is rapid (a chromatographic run time of 2 min) and can easily be performed (no laborious clean-up). The presented method is environmental friendly with significant reduction in solvent consumption.

Topics: Chromatography, High Pressure Liquid; Drug Stability; Ethylenethiourea; Fruit; Fungicides, Industrial; Linear Models; Pesticide Residues; Reproducibility of Results; Sensitivity and Specificity; Tandem Mass Spectrometry; Thiocarbamates; Thiourea; Vegetables

A simple, rapid and sensitive GC-MS method for the determination of dithiocarbamate fungicide propineb [polymeric zinc propylenebis (dithiocarbamate)] and an improved HPLC procedure for the simultaneous determination of its main metabolite, propylenethiourea, and ethylenethiourea, the main metabolite of all ethylenedithiocarbamates, in airborne samples are described. The method for the analysis of propineb involves the evolution of carbon disulfide (CS(2)), under acidic conditions in the presence of stannous chloride, extraction of the generated CS(2) into a layer of isooctane which is then analyzed for CS(2) content by GC-MS in SIM mode. Under the optimum conditions, the retention time of CS(2) was 1.89 min and the total time of chromatographic analysis was 5 min. Recoveries from spiking glass microfibre filters (GF/A) and silica gel filters were 86+/-7 (n=9) and 89+/-4 (n=9), respectively. The limit of detection is 0.7 ng per filter, which is equivalent to about 0.8-1.0 ng m(-3) in air. In parallel, an HPLC method with ultraviolet detection is presented for the simultaneous analysis of the metabolites. Separation of the two metabolites was attained in less than 5 min. Recoveries from spiking GF/A and silica gel filters for ethylenethiourea were 100+/-1 (n=3) and 98+/-2 (n=3), respectively, while for propylenethiourea were 102+/-1 (n=3) and 98+/-1 (n=3), respectively. The detection limits are about 36-43 and 40-49 ng m(-3) in air for ethylenethiourea and propylenethiourea, respectively. All the analytes spiked in the filters are proven to be stable for more than one month, at -4 degrees C.

Topics: Air Pollutants; Environmental Monitoring; Molecular Structure; Thiourea; Zineb

Because of increasing concern about widespread use of insecticides and fungicides, we have developed a highly sensitive analytical method to quantify urine-specific urinary biomarkers of the organophosphorus pesticides acephate, methamidophos, omethoate, dimethoate, and two metabolites from the fungicides alkylenebis-(dithiocarbamate) family: ethylenethiourea and propylenethiourea. The general sample preparation included lyophilization of the urine samples followed by extraction with dichloromethane. The analytical separation was performed by high-performance liquid chromatography (HPLC), and detection by a triple quadrupole mass spectrometer with and atmospheric pressure chemical ionization source in positive ion mode using multiple reaction monitoring and tandem mass spectrometry (MS/MS) analysis. Two different Thermo-Finnigan (San Jose, CA, USA) triple quadrupole mass spectrometers, a TSQ 7,000 and a TSQ Quantum Ultra, were used in these analyses; results are presented comparing the method specifications of these two instruments. Isotopically labeled internal standards were used for three of the analytes. The use of labeled internal standards in combination with HPLC-MS/MS provided a high degree of selectivity and precision. Repeated analysis of urine samples spiked with high, medium and low concentration of the analytes gave relative standard deviations of less than 18%. For all compounds the extraction efficiency ranged between 52% and 63%, relative recoveries were about 100%, and the limits of detection were in the range of 0.001-0.282 ng/ml.

Topics: Atmospheric Pressure; Child; Chromatography, High Pressure Liquid; Dimethoate; Ethylenethiourea; Female; Humans; Insecticides; Organothiophosphorus Compounds; Phosphoramides; Pregnancy; Tandem Mass Spectrometry; Thiourea

A robust and sensitive method for the determination of ethylenethiourea (ETU) and iso-propylenethiourea (i-PTU) in foods is reported. ETU and i-PTU were extracted by blending with dichloromethane (DCM) in the presence of sodium sulphate, sodium carbonate, thiourea and ascorbic acid. 2H4-ETU and n-PTU were used as internal standards. After filtration the DCM was removed by rotary evaporation and the extract re-dissolved in water before analysis by reversed-phase liquid chromatography with detection by atmospheric pressure chemical ionization-mass spectrometry using a double focusing mass spectrometer at a resolution of 5000. Mean recoveries of ETU and i-PTU from fruit-based, cereal-based and meat-based infant foods, potato chips and tinned potatos at 0.01 mg kg(-1) and from pizza and yoghurt at 0.02-0.1 mg kg(-1) were 95% and 97% respectively. Precision, including both repeatability and internal reproducibility, was in the range of 3.1-13.1%.

Topics: Chromatography, High Pressure Liquid; Ethylenethiourea; Food Analysis; Food Contamination; Food Handling; Fungicides, Industrial; Mass Spectrometry; Oxidation-Reduction; Reproducibility of Results; Thiourea

After repeated-dose toxicity studies with the fungicide propineb, reversible effects on muscle functions were found. Therefore, mechanistic investigations should contribute to clarification of its mode of action in relation to disulfiram and diethyldithiocarbamate neurotoxicity or direct effects on muscle cells. In principle, besides the dithiocarbamate effects, two different mechanisms have been discussed for this fungicide. One mechanism is the degradation to carbon disulfide (CS(2)) and propylenthiourea (PTU) and the other are direct effects of zinc. Primary neuronal cell cultures of the rat are a well established model to identify neurotoxic compounds like n-hexane or acrylamide. In this cell culture model, endpoints such as viability, energy supply, glucose consumption and cytoskeleton elements were determined. Additionally, skeletal muscle cells were used for comparison. Propineb and its metabolite PTU were investigated in comparison to CS(2), disulfiram and diethyldithiocarbamate. The toxicity of zinc was tested using zinc chloride (ZnCl(2)). It was clearly shown that propineb exerted strong effects on the cytoskeleton of neuronal and non-neuronal cell cultures (astrocytes, muscle cells). This was similar to ZnCl(2,) but not to CS(2). With CS(2) and disulfiram effects on the energy supply were more prominent. In conclusion, the toxicity of propineb is not comparable to disulfiram, diethyldithiocarbamate or CS(2) neurotoxicity. In regard to these findings, a direct reversible effect of propineb on skeletal muscle cells seems to be more likely.

Topics: Animals; Carbon Disulfide; Cell Survival; Cells, Cultured; Cerebral Cortex; Chlorides; Cytoskeleton; Disulfiram; Ditiocarb; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Fungicides, Industrial; Glucose; Muscle, Skeletal; Neurons; Rats; Thiourea; Zinc Compounds; Zineb

The teratogenic and goitrogenic effects of Propineb, dithiocarbamate pesticide and Propylenthiourea (PLTU), its metabolite and degradation product have been studied. The aim of this study was to show the possible correlation between the two activities. Female Sprague-Dawley rats were treated with Propineb and PLTU starting from 6th to 16th day of pregnancy. The functional state of maternal and foetal thyroid, the toxicity of products versus dams and embryotoxic and teratogenic effects were examined. The observed goitrogenic effect may be compared to that reported in the previous studies of the authors, if considering time of sacrifice. In fact, the lesion quickly rises and as rapidly regresses when treatment is stopped. The foetal thyroid has not been affected by the product administered to the dams. PLTU showed a clear teratogenic activity at doses that did not show any maternal toxicity (45 and 90 mg/k).

Topics: Animals; Antithyroid Agents; Female; Fungicides, Industrial; Pregnancy; Pregnancy Complications; Rats; Rats, Inbred Strains; Teratogens; Thiocarbamates; Thiourea; Zineb

The possible clastogenic activity of Propineb, Propineb technical grade and of its main metabolite, propylene-thiourea (PLTU), was investigated by the micronucleus test in mice according to Schmid. No statistically significant increase in the percentage of micronuclei was observed at any of the tested doses of the above compounds. As positive controls, dose-effect curves were constructed for methyl methanesulfonate (MMS) and mitomycin C (MMC).

Topics: Animals; Antibiotics, Antineoplastic; Cell Nucleus; Erythrocytes; Female; Male; Methyl Methanesulfonate; Mice; Mitomycin; Mitomycins; Mutagenicity Tests; Mutagens; Mutation; Thiocarbamates; Thiourea; Zineb

Topics: Animals; Chromatography, Gas; Female; Pregnancy; Rats; Thiourea; Tissue Distribution