A gas chromatography–mass spectrometry assay was developed and validated for the simultaneous determination of phthalates and adipates in human serum. The phthalates and adipates studied were dimethyl phthalate, diethyl phthalate, dibutyl phthalate, benzylbutyl phthalate, di‐2‐ethylhexyl phthalate, di‐n‐octyl phthalate, diethyl adipate, dibutyl adipate, diisobutyl adipate, bis(2‐butoxyethyl) adipate and di‐2‐ethylhexyl adipate, with diisooctyl phthalate as internal standard. The extraction and cleaning up procedure was carried out with solid‐phase extraction cartridges containing dimethyl butylamine groups, which showed extraction efficiencies over 88% for each analyte and the internal standard. The calibration curves obtained were linear with correlation coefficients greater than 0.98. For all analytes, the assay gave CV% values for intra‐day precision from 4.9 to 13.3% and mean accuracy values from 91.4 to 108.4%, while inter‐day precision was 5.2–13.4% and mean accuracy 91.0–110.2%. The limits of detection for the assay of phthalates and adipates were in the range 0.7–4.5 ng/mL. The method is simple, sensitive and accurate, and allows for simultaneous determination of nanogram levels of phthalates and adipates in human serum. It was successfully applied to an investigation on the level of phthalates and adipates in a non‐occupationally exposed population. 相似文献
A study of the thermal decomposition, in air, of praseodymium and neodymium adipate and sebacate has suggested the decomposition pattern which follows (An represents either adipate or sebacate). The compounds were prepared by homogeneous precipitation.For the adipates formed at pH greater than 5 as well as for the sebacates precipitated at any pH: The sebacates were precipitated quantitatively at pH greater than about 5.1; precipitation of the adipates was incomplete even at values of pH as high as 8.8. The adipates were thermally stable up to 180°C whereas the sebacates underwent slow decomposition at temperatures close to 100°C. 相似文献
A number of new dialkyl 2-(5-trisubstitutedsilyl)thienylphosphonates and thiophosphonates as well as dialkyl 2-(5-trisubstitutedsilyl)furylphosphonates and thiophosphonates were prepared via reaction of the 5-(trisubstitutedsilyl)-2-lithiothiophenes and furans with dialkyl chloro-phosphate and dialkyl chlorothiophosphate. Moreover, some diethyl 2-[5-(trisubstitutedsiIyl)-2-thienyl] ethyl thiophosphates are reported. 相似文献
Crystalline dialkyl esters of arylamino(2-pyridyl)methylphosphonic acids have been synthesized by the reaction of 1-pyridylazomethines with dialkyl phosphites in the presence of sodium alkoxides. When -pyridinealdehyde was condensed with dialkyl phosphites in the presence of sodium alkoxides, dialkyl esters of hydroxy(2-pyridyl) methylphosphonic acids were obtained in the form of viscous liquids. These compounds were identified in the form of the crystalline methiodides. 相似文献
Two kinds of capillary columns were prepared and tested as the stationary phases of ligand exchange gas chromatographic separation of dialkyl sulfides. The PTFE column wall-coated with silane-DTC-Cu but without the addition of silicone exhibits significantly better selectivity towards dialkyl sulfides than a column wall-coated with 10% silane-DTC-Cu in silicone. With the first column connected to a microsample injection valve and a microsample loop, the quantitative determination of dialkyl sulfides can be performed. The column also shows great promise for the separation of dialkyl sulfide-hydrocarbon mixtures. 相似文献
Microwave heating technique was applied to the preparation of dialkyl dithiophosphoric acids from the reaction of alcohol with phosphorus pentasulphide. A microwave oven (CEM-MDS 2000) was utilized to determine the preparation conditions for the best yield of dialkyl dithiophosphoric acids under atmospheric pressure at various times and power. Six different (C 4 -C 9 ) chain-length of dialkyl dithiophosphoric acids were studied. All experiments were performed in an open Teflon (poly-tetrafluoroethylene) vessel. The results obtained showed that the reaction of dialkyl dithiophosphoric acids can be achieved more rapidly using microwave heating than using conventional procedures. 相似文献
Studies on the selective synthetic method for dialkyl ditellurides 1, a representative class of organyl tellurium compounds, were presented. Considering the difficulty in conducting previous harsh reactions and in suppressing the formation of dialkyl tellurides 2 as side products, we optimized reaction conditions for selective syntheses of sodium ditelluride and the corresponding dialkyl ditellurides 1. We reduced tellurium to sodium ditelluride by using NaBH4 and subsequently, treated the obtained sodium ditelluride with alkyl halides (RX) to give the target compounds 1. Consequently, by applying various alkyl halides (RX) we achieved the selective syntheses of dialkyl ditellurides 1 (13 examples with 4 new compounds) in modest to good yields. We also suggested the mechanistic pathways to dialkyl ditellurides 1. 相似文献
The reaction of dialkyl acetylenedicarboxylates with arylidenemalononitriles in the presence of KSCN in MeCN led to a mixture of dialkyl (3E)‐4‐aryl‐3‐(arylideneamino)‐5,5‐dicyanocyclopenta‐1,3‐diene‐1,2‐dicarboxylates and dialkyl 4‐aryl‐5‐cyanothiophene‐2,3‐dicarboxylates. When these reactions were performed in the presence of KCN, only the functionalized 5,5‐dicyanocyclopenta‐1,3‐dienes were obtained. 相似文献
Abstract Acetylacetone and its related compounds were transformed into the dialkyl 1-methyl-1-trimethylsiloxyl-3-oxo-butylphosphonates, which after treatment with trifluoroacetic acid were converted into the dialkyl 1-methyl-3-oxo-1-butenylphosphonates. 相似文献