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991.
992.
目的 基于Lasso变量筛选和XGBoost模型探讨人体农兽药及化学污染物暴露水平与糖尿病患病风险相关性。方法 2018—2019年,在中国石家庄和杭州进行的“降低成年超重者营养相关慢性病风险的适宜身体活动量研究”调查,选取86例糖尿病患者与410例非糖尿病患者样本并提取问卷调查中个人基本情况数据、体格测量、血生化数据和血清农兽药及化学污染物暴露浓度数据。采用Lasso筛选变量,再分别引入逻辑回归模型与XGBoost模型进行拟合,比较AUC评估拟合效果,并进行变量重要性排序。结果 Lasso筛选出2-乙基己基二苯基磷酸酯、全氟辛酸与全氟十一烷酸3种农兽药及化学污染物暴露与人群糖尿病患病有关,重要性排序为全氟辛酸>2-乙基己基二苯基磷酸酯>全氟十一烷酸,XGBoost模型(AUC=0.83)显著优于逻辑回归模型(AUC=0.64)(P<0.05)。结论 Lasso适用于糖尿病患病影响因素的筛选,且XGBoost模型具有较好的复杂数据拟合能力。2-乙基己基二苯基磷酸酯、全氟辛酸与全氟十一烷酸是人群糖尿病患病的重要影响因素。 相似文献
993.
目的 基于表面增强拉曼光谱技术,建立一种叶菜类蔬菜中噻虫嗪农药残留拉曼快速检测的方法。方法 以金纳米溶胶为增强基底,采用具有多孔结构的碳纳米笼材料作为净化剂,利用其比表面积大、吸附能力强的特性,去除蔬菜基质中的色素、有机酸等干扰,实现高灵敏度检测。结果 本方法检出限可达1 mg/kg,在噻虫嗪浓度0.5~15 mg/kg范围内,线性关系良好,回收率为90.7%~121.7%,相对标准偏差为2.3%~7.5%。结论 本方法灵敏度高、操作简单快速,适用于基层监管部门蔬菜中噻虫嗪农药残留的快速检测。 相似文献
994.
995.
《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(5):826-832
Supervised field trials were carried out in a commercial orchard in 2011. The purpose of the study was to assess the usefulness of the comparative method to examine the mechanism of disappearance of pesticide residues. Captan and trifloxystrobin residues were determined with the use of gas chromatograph equipped with a micro-electron capture detector. Disappearance trends of captan and trifloxystrobin residues in fruit and leaves were estimated using the method of internal normalisation, and based on that, the courses of concentration changes of these substances on fruit and leaves and the amount of these substances in one apple were established. The initial deposits of trifloxystrobin on leaves and fruits dropped by 50% within 8 and 4 days after treatment, respectively, in both varieties, whereas captan residues dropped by 50% within 29 days in leaves and 7 days in apples of the Olive Yellow varieties. 相似文献
996.
M. Gaugain-Juhel B. Delépine S. Gautier M.P. Fourmond V. Gaudin D. Hurtaud-Pessel 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(11):1459-1471
A multi-residue method was developed for monitoring antibiotic residues in milk using liquid chromatography coupled to a tandem quadrupole mass spectrometer (LC/MS-MS). Two very short extractions followed by two LC/MS-MS acquisitions allowed the screening of 58 antibiotics belonging to eight different families (penicillins, cephalosporins, sulfonamides, macrolides, lincosamides, aminoglycosides, tetracyclines, and quinolones). This method is currently implemented in the laboratory in a qualitative way, i.e. monitoring the presence or absence of residue in a sample and identification of the analyte before the confirmation step. In order to assess the performance of this method, a validation strategy described in an internal guideline for the validation of screening methods was applied. The aim of the validation was to prove sufficient sensitivity of the method to detect all the targeted antibiotics at the level of interest (maximum residue limit, MRL) at least. According to European Commission Decision 2002/657/EC, the suitable sensitivity of a screening method can be demonstrated when the CCβ is below or equal to the MRL and so the false-compliant rate below or equal to 5% at the MRL level. The validation scheme was established in order to take into account various variability factors: the apparatus response, the interday repeatability, the matrix effect, etc. The results of the validation clearly demonstrate the suitability of this method for the detection and identification of more than 50 antibiotics and they are in agreement with the results obtained in routine analysis. 相似文献
997.
Stefan Weigel Mariel G. Pikkemaat J.W. Alexander Elferink Patrick P.J. Mulder Anne-Catherine Huet Philippe Delahaut 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(4):441-452
The performance of a previously developed immunochemical biosensor screening method for fluoroquinolone (FQ) antibiotics in poultry muscle, fish and egg was compared with established methods. Blank sample material of the target matrices was individually spiked with the FQs at half maximum residue levels. Homogeneity of the test materials was confirmed by liquid chromatography–mass spectrometry (LC–MS/MS). Identical sets of spiked samples as well as incurred samples from a previous feeding experiment were sent to three independent laboratories and analysed by LC–MS/MS, a microbiological assay and the new biosensor assay. The new method correctly identified all contaminated samples and demonstrated advantages in sensitivity and analysis time compared to the microbiological screening assay. 相似文献
998.
《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(6):1081-1088
The effect of home canning (including washing, boiling, cooling, adding solution and sterilisation) on residue levels of imidacloprid, diflubenzuron, abamectin, pyriproxyfen and β-cypermethrin and chlorothalonilin on button crimini was assessed. Residues of imidacloprid, diflubenzuron, abamectin and pyriproxyfen were measured by UPLC-MS/MS; the residues of β-cypermethrin and chlorothalonil were measured by GC. Results showed that washing resulted in a 3.8% reduction of the initial residue level of imidacloprid (p ≤ 0.05). From washing to sterilisation the processing effect was significant compared with raw crimini (p ≤ 0.05), but processing through cooling and adding solution had no effect. For diflubenzuron, from raw crimini to sterilisation the processing effect was significant by comparison with the initial level (p ≤ 0.05); the processing effect was not obvious between two sequential steps, and the sequential steps have list: washing and boiling, boiling and cooling, boiling and adding of solution, cooling and adding solution. The changes in abamectin levels were also significant from raw crimini to sterilisation compared with raw crimini (p ≤ 0.05), but the changes were not obvious from boiling to adding solution and amongst them. For pyriproxyfen, washing resulted in a 39% reduction, but changes were not obvious from washing to sterilisation, p ≤ 0.05 between two consecutive steps. The whole procedure could significantly decrease residues of β-cypermethrin (p ≤ 0.05); washing could significantly reduce residues of β-cypermethrin; the effects of last procedures were complicated, and p ≤ 0.05 between two consecutive steps. Washing resulted in an 80% reduction of chlorothalonil; after washing there were no detectable residues. After the whole process, the processing factors for imidacloprid, diflubenzuron, abamectin, pyriproxyfen, β-cypermethrin and chlorothalonil were 0.40, 0.22, 0.04, 0.85, 0.28 and 0, respectively. 相似文献
999.
In northern Cameroon, the misuse of pesticides for pest control is common among small-scale farmers. Therefore, monitoring of pesticide residues was carried out on stored maize, cowpea and millet from eight localities. The determination of residues of organochlorines (lindane, α-endosulfan and β-endosulfan), organophosphorus compounds (malathion and pirimiphos-methyl), synthetic pyrethroids (permethrin) and carbamates (carbufuran) was performed using GC–ECD/NPD and GC–MS for confirmation. Organochlorine pesticides were detected more frequently and in higher concentrations, ranging from 0.02 ± 0.01 mg kg?1 for β-endosulfan in millet to 9.53 ± 4.00 mg kg?1 lindane in maize, than organophosphorus compounds, with concentrations varying from 0.04 ± 0.03 mg kg?1 for pirimiphos methyl to 0.23 ± 0.38 mg kg?1 for malathion in maize. Permethrin was found only in maize at 0.39 ± 0.23 mg kg?1. No carbofuran was found. More than 75% of samples contained pesticide residues above the maximum residue limit (MRL); showing a potential human dietary risk related to consumption of these grains. 相似文献
1000.
ABSTRACTA total of 160 samples of 13 types of fresh fruits and vegetables from domestic production and import were analysed to detect the presence of pesticide residues. Analysis was performed by multi-residual extraction followed by gas chromatography–mass spectrometry. In 42.5% of the tested samples, no residues were found and 12.5% of samples contained pesticide residues above maximum residue limits. Risk assessment for long-term exposure was done for all pesticides detected in this study. Except chlorpyrifos and lambda-cyhalothrin, exposure to pesticides from vegetables and fruits was below 1% of the acceptable daily intake. Short-term exposure assessment revealed that in seven pesticide/commodity combinations, including three pesticides (chlorpyrifos, deltamethrin and lambda-cyhalothrin), the acute reference dose had been exceeded. 相似文献