共查询到18条相似文献，搜索用时 182 毫秒
1.
本文对茶叶中7种有机氯类和拟除虫菊酯类农药残留检测的前处理技术进行了研究,对比了2种不同的提取溶剂对农药回收率、净化效果的影响,建立了丙酮∶正己烷(1∶1,V/V)提取,Florisil固相萃取小柱净化的方法。本方法回收率在82.3～109.8%之间,变异系数3.3～10.22%,最低检出浓度为0.001mg/kg。该种残留分析前处理方法具有操作简便、成本低、回收率高、精密度好的特点。 相似文献
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为了解人参不同部位中农药残留分布规律及膳食风险，分别取黑龙江省鸡东市2、3、4年参，虎林市2、3、4、5、6年参，针对其芦头、主根及须根建立了气相色谱-质谱联用(GCMS)检测技术，分别测定了其中五氯硝基苯、六氯苯及毒死蜱的残留量，并就人参中3种农药残留的短期膳食风险进行了评估。72份人参样品中，五氯硝基苯检出率为74%，检出残留量在0.005～0.062 mg/kg之间；六氯苯检出率为78%，残留量在0.057～0.150 mg/kg之间；毒死蜱检出率为61%，残留量在0.018～0.073 mg/kg之间。2020版《中国药典》规定人参中五氯硝基苯和六氯苯的最大允许残留限量(MRL)均为0.1 mg/kg，所检测样品中，虎林市5、6年参芦头及6年参主根中六氯苯的残留量超过了该限量标准，超标率分别为2.8%、5.6%和2.8%。总体而言，农药残留水平随人参种植年份的增加而升高，人参各部位中累积的农药残留量由高到低分别为芦头>主根>须根，同时其短期膳食风险商(RQST)远小于100%，说明通过人参摄入的农药残留对人体不会产生不可接受的短期膳食暴露风险。 相似文献
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本文研究了液液萃取-气相色谱方法测定水体中有机氯和菊酯类农药残留的方法。用环己烷从水体中提取净化45种农药残留,运用GC-ECD进行分析。用外标法定量,加标浓度分别为0.005,0.05,0.1μg/mL时,回收率在70.36~114.96%之间,相对偏差≤10%。方法检出下限为0.001~0.005μg/mL,用该方法可实现对水体中农药残留的检测。 相似文献
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基于人参样品基质特点,采用快速滤过型净化法 (m-PFC) 结合高效液相色谱-串联质谱 (HPLC-MS/MS),建立了人参中嘧菌酯、苯醚甲环唑、吡虫啉、茚虫威和噻嗪酮5种农药残留同时检测的分析方法。该方法具有较低的检出限 (0.03~0.18 μg/kg) 和定量限 (0.11~0.59 μg/kg),其定量限较中国国家标准GB 2763—2016中规定的对人参中苯醚甲环唑和嘧菌酯的最大残留限量 (MRL) (0.5~1 mg/kg) 低3个数量级,5种农药的线性范围在1~500 μg/L之间。在2、10、50、100和300 μg/kg的添加水平下,方法的平均回收率均在76%~115%之间,相对标准偏差 (RSD) 均小于11%,回收率较好且方法稳定。与传统样品前处理方法相比,该方法具有操作简单、省时省力和灵敏度高等优点。将该方法应用于市售6份人参样品中5种农药残留的检测,结果未检出相应的农药残留。该方法为研发建立更快速、准确地检测人参中农药残留的方法提供了思路,也为后续中国国家标准修订人参中农药最大残留限量提供了参考。 相似文献
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建立了水体中29种农药的固相萃取-气相色谱检测方法。以Envi-18固相萃取小柱提取水样中的各种农药,上样体积为200 mL,洗脱溶剂为正己烷-丙酮(1∶1,体积比)。在添加水平为0.1、1.0和10 μg/L时,水样中29种农药的添加回收率为60%~111%,相对标准偏差(RSD)为1.2%~6.4%,方法的检出限(LOD)为5~50 ng/L。所建立方法准确、灵敏、快速,符合水体中多种农药残留检测分析的要求,且对水体中低浓度残留农药的检测效果较好。 相似文献
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本研究建立并验证了一种快速检测4种人参制品(人参蜜片、人参水煎液、人参功能饮料、人参酒)中39种农药残留的方法。样品采用QuEChERS法提取，磁性氧化锆(Fe3O4-ZrO2)净化，超高效液相色谱-串联质谱法(UHPLC-MS/MS)检测，外标法定量。结果表明：39种农药在0.005～0.1 mg/L范围内线性良好(r> 0.99)；在4种人参制品基质中的平均回收率为72%～117%，相对标准偏差(RSD)小于18%；定量限(LOQ)为0.01 mg/kg。通过对4种人参制品实际样品的筛查，未检出方法中所包含的农药。 相似文献
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快速溶剂萃取/气相色谱测定果蔬中有机氯农药残留的研究 总被引：10，自引：1，他引：9
建立了使用快速溶剂萃取（ASE）技术提取,毛细管柱为分离柱,以电子捕获检测器检测,用气相色谱法同时测定果蔬中15种有机氯农药的残留量.与国标法--振荡萃取法（MSE）相比,在保证足够的准确度的前提下,具有前处理时间短、所用试剂少的特点.用该方法测试的结果表明,在5种果蔬中填加一定浓度的待测物时,各种待测物的回收率均在85.7%～108.5%之间;相对标准偏差（RSD）为1.9%～9.5%（6次测定平均值）;最低检出限为1.1～20μg/kg.之间,结果表明,使用ASE萃取果蔬中有机氯农药符合国标规定的农药残留检测的需要. 相似文献
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人参中18种有机氯农药多残留分析方法 总被引：1，自引：0，他引：1
建立了人参中18种有机氯农药及其异构体残留量的气相色谱分析方法。样品以30mL石油醚-丙酮(1∶ 1,体积比)为提取剂,冰浴超声提取15 min,重复2次,提取液用浓硫酸净化,采用HP-5与DB1701毛细管色谱柱双柱定性分离,气相色谱-电子捕获检测器(GC-ECD)测定。结果表明:该方法在10、50、100 μ g/kg 3个水平下的添加回收率除艾氏剂与苯氟磺胺在62%左右外,其余 分别在75.1%~107.7%、72.1%~98.6%和71.5%~105.4%,相对标准偏差(RSD)分别为2.5%~ 11.3%、2.6%~12.5%和1.1%~11.2%;方法的检出限为3.14 μ g/kg,定量限为10 μ g/kg。 相似文献
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嘧菌酯在人参和西洋参中的残留监测及其膳食风险评估 总被引：2，自引：1，他引：1
建立了气相色谱-电子捕获检测器(GC-ECD)测定中药材人参和西洋参中嘧菌酯残留的分析方法。 样品经乙腈-水 [V (乙腈):V (水)=7 :1]提取,柱层析 [m(弗罗里硅土):m(中性氧化铝):m(活性炭)=5 :3 :0.15)及液-液分配净化,GC-ECD检测。结果表明,当嘧菌酯在人参和西洋参中的添加水平分别为1、0.5和0.01 mg/kg时,回收率分别为82.1% ～97.8%和90.9% ～92.0%,相对标准偏差(RSD)分别为1.6% ～6.2%和1.6% ～3.1%,均符合农药残留分析要求。仪器的最小检出量(LOD, S/N =3)为0.06 ng,方法的最低检测浓度(LOQ)为0.01 mg/kg。采用所建立方法调查了2010年不同来源人参和西洋参样品中嘧菌酯的残留情况,并对其膳食风险进行了初步评估。结果表明,样品中嘧菌酯的最大残留量为0.1 mg/kg,计算得出的风险商(RQ)值很小,处于安全水平。 相似文献
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Keith A. Scudamore 《Pest management science》1987,18(1):33-53
Two alternative cold solvent extraction mixtures, (a) light petroleum distillate (40–60°C boiling range) + 0.1-M hydrochloric acid (2+3 by volume) and (b) acetone + water (5+1 by volume), were examined for their effectiveness in extraction of residues of bromochloromethane, 1,1,1-trichloroethane, carbon tetrachloride and 1,1,2-trichloroethylene from cereal grains and rape seed. Apparent recoveries of fumigants from spiked solutions or spiked commodity extracts were generally in the range 90-105%, acetone + water giving the higher results. For most fumigated samples extracted shortly after treatment, comparative results obtained for the two extraction mixtures were similar to those obtained for spiked extracts and this, together with rapid rates of extraction, suggested that almost complete extraction from the commodities had been obtained. However, the rate of extraction of residues from aged samples using either solvent mixture was often slow, with extraction continuing well beyond the recommended standing periods. Agreement in results obtained was significantly improved by standing for longer periods, in order that equilibrium of residual compounds between commodity and solvent could be reached. However, low results were obtained using light petroleum distillate + hydrochloric acid to extract all four fumigants from rape seed and bromochloromethane from oats. It is recommended that the effectiveness of the solvent mixture selected for extraction of this type of volatile residue from cereal grains is carefully checked, especially when determining residues in aged samples or samples of unknown history. 相似文献
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采用超临界流体萃取-反相高效液相色谱法,以鱼藤酮萃取率和萃取产物总得率为评价指标,研究提出非洲山毛豆Tephrosia vogelii Hook.f中鱼藤酮的超临界流体萃取较优工艺条件为:萃取物料粒径30目,静态萃取20 min,萃取温度45℃,压力27.58 MPa,流体总流量30 mL/g,萃取前向萃取池中加入3 mL甲醇作夹带剂。采用该法对非洲山毛豆中鱼藤酮的萃取率(质量分数)达0.41%,相当于氯仿浸提法的98%;萃取产物总得率(质量分数)为16.62%,高于氯仿浸提法。与常规溶剂法相比,该方法具有萃取效率高、精确、无毒、经济、操作简便、选择性可调等优点。 相似文献
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Soxhlet extraction with hexane + acetone (1 + 1 by volume) was used for the extraction of organochlorine pesticide residues from river sediments, followed by Florisil column chromatography clean-up and determination by gas chromatography with an electron-capture detector. Average recoveries exceeding 90 % were obtained using this technique. Organochlorine pesticide residue levels in sediment samples from two major rivers flowing through predominantly rice-growing areas were determined by this method. Relatively high residue levels of organochlorine pesticides such as HCH, heptachlor and endosulfan were found in the sediments. 相似文献
14.
Allan E. Smith 《Pest management science》1978,9(1):7-11
The extraction from several field soils of the four herbicides benzoylprop-ethyl, nitrofen, profluralin, and tri-allate applied at least 6 months previously was compared using six solvent systems. The residues extracted were quantified using gas chromatographic techniques. Similar recoveries were achieved using 30% aqueous acetonitrile or acetonitrile + water + glacial acetic acid mixtures. The presence of the acetic acid was found to increase residues extracted only in the case of tri-allate. Methanol and 10% aqueous acetonitrile were slightly less efficient in recovering residues from the weathered field soils whereas acetone tended to be a poor solvent for the extraction of the chemicals studied. 相似文献
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A sensitive method for the detection and estimation of residues of the molluscicide, niclosamide, in bananas is described. The procedure involves extraction of the molluscicide, purification of the extract by solvent partition and column chromatography, formation of the heptafluorobutyryl derivative of 2-chloro-4-nitroaniline in 99% yield and determination of the derivative by gas—liquid chromatography with electron-capture detection. Recoveries from fortified bananas were 89 and 79% at levels of 0.02 and 0.2 mg kg?1, respectively. The sensitivity of the method was such that 0.6 pg of the pure derivative could be detected, based on twice the background noise level on the chromatograph. 相似文献
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Alternative methods for the extraction of unchanged carbon tetrachloride residues from fumigated whole and ground wheat and maize were examined and compared. Amounts of carbon tetrachloride extracted were determined by gas-liquid chromatography using two separate columns and an electron-capture detector. A portion of any carbon tetrachloride residue was found to be converted to chloroform by a steam distillation extraction method but not when a cold solvent extraction process was used. In addition, the effectiveness of removal of carbon tetrachloride from wheat and maize during a 3.5 h steam distillation was progressively lessened, in comparison with the cold extraction process, as the length of time that residual fumigant had been associated with the grain increased. The rate of elimination of carbon tetrachloride from wheat and maize during airing at two temperatures was determined and though partially dependent on the temperature of fumigation, airing was consistently more rapid at 25° than at 10°C. Initial residues of 200 to 400 parts/million in whole grains fell to 1 to 10 parts/million when aired for six months in thin layers at 25°C and to 5 to 50 parts/million at WC. Residues in wheat disappeared more rapidly than those in maize. Grinding initially caused a sharp reduction in carbon tetrachloride content but subsequent airing rates were little faster than those of the whole grains. It is concluded that complete elimination of trace amounts of carbon tetrachloride from products of treated grain is unlikely even after milling but the toxicological significance of such residues is uncertain. 相似文献
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The extent to which methyl bromide was retained by fumigated material after treatment was followed in laboratory studies on a range of commodities exposed to the vapour at atmospheric pressure. Amounts of methyl bromide, recovered by solvent extraction and determined using gas-liquid chromatography, were related to the temperature, moisture content and manner of post-treatment storage. Immediately after exposure, the initial amount of free methyl bromide present was more dependent on the gas concentration used than on the time of exposure. Under the experimental conditions of exposure, the residual free methyl bromide in all commodities fumigated at 25°, except cocoa beans and groundnuts, fell to below 1 ppm within a few days when they were held at that temperature, whether spread in thin layers on trays or kept sealed in glass bottles. At lower temperatures, the rate of loss was slower, small amounts of methyl bromide being extracted from several commodities one month after treatment. The disappearance of fumigant from wheat and sultanas was more rapid from samples with higher moisture contents. A mathematical treatment of the data is presented, to assist in prediction of the behaviour of residual fumigant under storage conditions before processing. It is concluded that the risk of ingestion of harmful quantities of free methyl bromide by the consumer is small and that the occasions when relatively high residues might occur can be predicted. 相似文献