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<p><b>OBJECTIVE</b>To develop an analytical method for simultaneous determination of 6 pesticides, namely bentazone, 2,4-dichlorophenoxyacetic acid,carbofuran, carbaryl, atrazine and pentachlorophenol, in drinking water by high performance liquid chromatography-tandem mass spectrometry, and thereby to provide a reference to revise the Health Standards for Drinking Water (GB/T 5750-2006). Meanwhile, to evaluate the content of the above 6 pesticides in the drinking water samples supplied by 12 centralized water plants in Jiangsu province.</p><p><b>METHODS</b>The 10 ml water sample was acidized by hydrochloric acid to pH ≤ 2, and then concentrated by solid phase extraction cartridge and eluted with acetone. The solvent was changed into methanol after drying by nitrogen blow. The target compounds were separated by C18 column using methanol/water as mobile phase, and detected by mass spectrometry with multi-reaction-monitoring(MRM) mode. The repeatability and sensitivity of the assay were evaluated. The drinking water samples from the 12 water plants were then detected.</p><p><b>RESULTS</b>In this experimental method, the minimum detectable concentration were around 0.02-0.41 µg/L, with the recovery rate at 75%-115%, and the RSD between 2% and 10%. Under the experimental condition, there were no pesticides detected in the drinking water samples from the 12 centralized water plants.</p><p><b>CONCLUSION</b>The method is efficient and environment-friendly, with little discharge of effluent, which could meet the requirement of the drinking water monitor.</p>
Subject(s)
Drinking Water , Pesticides , Solid Phase Extraction , Methods , Tandem Mass Spectrometry , Methods , Water Pollutants, ChemicalABSTRACT
<p><b>OBJECTIVE</b>To assess the current status of the acrylamide in the Chinese food supply, the dietary acrylamide exposure in the Chinese population and to estimate the public health risks of the current consumption.</p><p><b>METHODS</b>The acrylamide content in the total diet study (TDS) food samples was analyzed using an LC-MS/MS method. Based on the analytical results, the dietary exposure calculations were performed using a deterministic method, combining mean acrylamide concentrations from the food group composite with their associated food consumptions.</p><p><b>RESULTS</b>Acrylamide was detected in 43.7% of all samples collected and acrylamide concentration varied from ND to 526.6 µg/kg. The estimated dietary intakes of acrylamide among Chinese general population given as the mean and the 95th percentile (P95) were 0.286 and 0.490 µg•kg(-1) bw•day(-1), respectively. The margins of exposure (MOEs) for the population calculated using both benchmark dose lower confidence limit for a 10% extra risk of tumors in animals (BMDL10) 0.31 and 0.18 µg•kg(-1) bw•day(-1), were 1069 and 621 for the mean dietary exposure, and 633 and 367 for the high dietary exposure respectively.</p><p><b>CONCLUSION</b>These MOE values might indicate a human health concern on acrylamide for Chinese population. Efforts should continue to reduce acrylamide levels in food in order to reduce the dietary risks to the human health.</p>
Subject(s)
Humans , Acrylamide , Chemistry , China , Diet , Environmental Exposure , Environmental Pollutants , Chemistry , Food Analysis , Food ContaminationABSTRACT
<p><b>OBJECTIVE</b>To establish a method for determining glyphosate in the air of workplaces by ion chromatography.</p><p><b>METHODS</b>Ultra-fine glass fiber filter paper was used to collect glyphosate from the workplace air. After being ultrasonically eluted with deionized water, samples were determined by ion chromatography using a conductivity detector.</p><p><b>RESULTS</b>Within the range of 0.05-1.00 mg/L, a linear relationship was found with a limit of detection of 0.003 mg/m(3). The minimum detectable concentration was 0.000 41 mg/m(3) (calculated by sampling 75 L of air). For three different concentrations of glyphosate, the intra-batch relative standard deviations (RSDs) were 1.8%, 1.6%, and 0.8%, respectively, and the inter-batch RSDs were 1.9%, 2.1%, and 2.2%, respectively. The recovery rate ranged from 94.8% to 97.4%. The elution efficiency ranged from 94.5% to 96.7%. The sampling efficiency was 100%. Samples could be stored at room temperature for at least 7 days.</p><p><b>CONCLUSION</b>This presented method meets the requirements of Guide for establishing occupational health standards-Part 4: Determination methods of air chemicals in workplace and is feasible for determination of glyphosate in the air of workplaces.</p>
Subject(s)
Air Pollutants, Occupational , Chromatography, Gas , Glycine , WorkplaceABSTRACT
Objective: To analyze the relationship between the calcification characteristics of middle cerebral artery (MCA) M1 segment and the cerebral infarction in its supplying areas. Methods: A total of 121 patients (151 arteries) with MCA M1 segment calcification in our hospital were diagnosed by CT from July to August 2005. The characteristics pattern of calcification, the location and its relation with the vessels were analyzed. Calcification scores were calculated using Cascoring automatic analysis software. Whether there were infarct foci and the numbers of infarct focus in the supplying areas of the bilateral MCA were determined. The incidence of cerebral infarction in MCA calcification group and MCA non-calcification group, as well as the relationship between with or without infarct foci in the MCA calcification group and the various calcification score indexes were analyzed statistically. Results: One hundred twenty-one arteries had sm all nodular calcifications, 18 had large nodular calcifications, and 12 had linear calcifications. The calcification of 76 arteries located in the proximal M1 segment, 55 in the middle M1 segment, and 20 in the distal M1 segment. The relationship between calcific plaques and arteries: centripetal 43 arteries, eccentric 108 arteries. The incidence of cerebral infarction (51.7%) in the MCA calcification group was higher than that of the non-calcification group (27.5%), and there was statistical significance between the 2 groups (P < 0.01). The calcific volume, mass and score in the infarcted group were greater than those in the non-infarcted group (P < 0.01), and there was also statistical significance between the 2 groups (P < 0.01). Conclusion: CT volume scan may show tiny calcifications in MCA, and may classify and determine the location of calcifications. Whether MCA calcification or not and calcification scores in various indexes are closely associated with the development of cerebral infarction. The calcification group is more likely to develop cerebral infarction than the non-calcification group. The severity of calcification in the infarcted is more serious than that of the non-infarcted group.
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Objective To investigate the possibility of MRI on visualizing the relationship between glossopharyngeal nerve and surrounding vessels,and to evaluate the significance of MRI in the diagnosis and treatment of glossopharyngeal neuralgia.Methods MRI findings were analyzed retrospectively in 12 patients with glossopharyngeal neuralgia,and were compared with surgical findings and effect of pain relief.Results The artery compression or contact of the glossopharyngeal entry zone,as revealed during operation in l0 patients with glossopharyngeal neuralgia,was visualized on MRI in 9 and not seen in 1.The venous compression of the glossopharyngeal entry zone was not identified on MRI in 1.The conglutinative arachnoids of the glossopharyngeal entry zone was not visualized on MRI in 1.MRI demonstrated the affected glossopharyngeal nerve root entry zone was compressed or contacted by the posterior inferior cerebellar artery (PICA)in 8 patients and by the vertebral artery in 1 patient.One patient's offending vessel was confirmed to be the anterior inferior cerebellar artery(AICA)by the operation,and the surgical findings were corresponded with MRI in others.Vascular compression or contact of the affected glossopharyngeal nerve was not visualized on MRI in 3 patients,and operation confirmed that the glossopharyngeal nerve root entry zone was compressed by unknown artery in 1,by small vein in 1,and by eonglutinative araehnoids in 1, respectively.Eight patients presented with symptoms of the ipsilateral trigeminal neuralgia concurrently.The compression of the affected trigeminal nerve root by superior cerebellar artery(SCA)was visualized on MRI in 6 patients,and operation did not reveal the source of artery compression in 1 and corresponded with MRI findings in other 5 cases.Vascular compression of affected trigeminal nerve was not visualized on MRI in 2 patients,and intraoperative inspection revealed that trigeminal nerve root was compressed by draining vein of brainstem in 1 and not compressed by any vessels in 1.All patient's neuralgia resolved after microvascular decompression of glossopharyngeal nerve and trigeminal nerve.Conclusion It is possible to visualize the glossopharyngeal and surrounding arteries on MRI,and it is of great significance in the diagnosis and treatment of this kind of glossopharyngeal neuralgia.