Investigations on the applicability of two ELISA types for the determination of chlorpyrifos in soil samples compared with a gas chromatographic method

Two commercially available ELISA kits for water analysis, a microtiter plate-ELISA based on polyclonal antibodies (p-ELISA) and a magnetic particle tube-ELISA based on monoclonal antibodies (t-ELISA), were used to determine chlorpyrifos residues in soils. Comparison with a gas chromatographic method frequently applied was carried out by fortification experiments and by analyses of real soil samples. At concentration levels of 1.0, 0.1, 0.05 and 0.01 mg/kg, chlorpyrifos was reliably determined by the GC method. Application of the p-ELISA did not permit a reliable quantitation, while the t-ELISA was applicable in a concentration range of 0.05–1.0 mg chlorpyrifos/kg dry soil. Received: 23 July 1997 / Revised: 10 November 1997 / Accepted: 14 November 1997     

30％毒死蜱微乳剂在甘蓝及土壤中的残留动态研究

利用气相色谱（配FPD检测器）分析测定了30％毒死蜱微乳剂在甘蓝和土壤中的残留消解动态和最终残留量。毒死蜱色谱峰面积与质量浓度在0．01～0．5mg／L范围内呈良好的线性关系,相关系数,为0．9992。甘蓝和土壤中毒死蜱的最低检出浓度均为0．005mg／kg,在0．01,0．02,0．1mg／kg3个添加水平下,甘蓝及土壤中毒死蜱的平均回收率分别为80．1％～96．4％和82．1％-98．7％,变异系数分别为1．2％～5．0％和2．5％-3-3％（n=10）。残留消解动态的结果表明：毒死蜱在甘蓝中的半衰期为5．8～10．5d,在土壤中的半衰期为8．0～10．5d。毒死蜱在收获期甘蓝及土壤中最终残留量均低于我国规定的限量值（1．0mg／kg）。     

Dissipation behavior of chlorpyrifos residues and risk assessment in sugarcane fields

As chlorpyrifos is used globally to control pests in sugarcane fields, analysis of its residues on food crops is essential to assess product safety for humans. In this study, chlorpyrifos content in sugarcane plants, soil and juice was determined using a gas chromatography with an electron capture detector. The limit of quantification was 0.01 mg/kg for plant and soil, and 0.01 mg/L for juice. The degradation and residual risk in sugarcane fields after applying chlorpyrifos to two sample sites (Changsha and Danzhou, China) were assessed. Chlorpyrifos concentrations in plants and soil decreased rapidly over time, reaching a degradation rate ranging from 98.82 to 99.25% on day 35. The half‐life of chlorpyrifos in both plants and soil was only 5.97–6.12 days. Regardless of application dosage (standard or high) at a pre‐harvest interval of 60 days, chlorpyrifos was undetectable in the harvested sugarcane. Risk assessment indicated that chlorpyrifos residue in sugarcane did not pose a health risk to humans.     

Determination of the residues of eleven organophosphorus insecticides in Job's-tears by gas chromatography with a nitrogen-phosphorus detector

A simplified method for determining 11 organophosphorus insecticides (dichlorvos, methamidophos, acephate, diazinon, dimethoate, chlorpyrifos, malathion, parathion, quinalphos, methidathion, and ethion) in the Chinese herbal medicine Job's-tears is described. Standards were fortified into Job's-tears (5 g) at 4 levels. The organophosphorus insecticides were extracted with dichloromethane and cleaned up with a mixture of Celite 545-activated carbon (4 + 1). The extracts were analyzed by gas chromatography using a nitrogen-phosphorus detector. Analysis of fortified Job's-tears shows average recoveries ranged from 73.90-98.70%, 86.31-93.15%, 84.92-96.22%, and 83.29-104.23% at 0.05, 0.1, 0.5, and 1.0 mg/kg levels, respectively. The minimum detectable amount ranged from 1.0 x 10(-10) to 5.0 x 10(-10) g, and the limit of quantitation for the method was 0.05 mg/kg. The method is rapid, simple, sensitive, reproducible, and applicable to the determination of these 11 organophosphorus insecticides in Job's-tears.     

高效液相色谱法测定柑橘和土壤中残留的多菌灵

建立了柑橘和土壤中多菌灵残留量的高效液相色谱(HPLC)分析方法。柑橘果肉、果皮、全果和土壤样品中残留的多菌灵用碱性乙腈溶液提取,经NH2固相萃取(SPE)柱净化,HPLC分离,紫外检测器检测,外标法定量。在0.02～5.0 mg/L范围内,多菌灵的峰面积与其质量浓度呈良好的线性关系,相关系数为0.9997。柑橘果肉、果皮、全果和土壤中添加0.05～0.5 mg/kg多菌灵标准品的平均回收率为89.2%～102%,相对标准偏差为1.8%～9.1%;柑橘果肉和土壤中多菌灵的最低检测浓度为0.05 mg/kg,柑橘果皮和全果中多菌灵的最低检测浓度为0.1 mg/kg。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。     

稻田土壤及水中多抗霉素残留量的分析与检测方法研究

采用高效液相色谱法建立了稻田土壤及水中多抗霉素残留量的分析方法。水样品经氨水调节pH值至8.0,以乙酸乙酯萃取去除有机杂质,水相经浓缩后定容;土壤样品用碱性甲醇和水的混合溶液(70∶30)提取,提取液经浓缩后定容。上述萃取液采用C18亲水性不锈钢色谱柱(AQ-C18,4.6 mm×250 mm,5μm)进行液相色谱分离,紫外检测器检测,外标法定量,流动相为水(用冰乙酸调节pH值为4.0)-甲醇(87∶13),流速:0～8 min为1.0 mL/min,8～16 min为0.3 mL/min,柱温30℃,检测波长272 nm。结果表明,多抗霉素的浓度在0.05～2.00 mg/L范围内与其对应的峰面积呈良好的线性关系,相关系数(r2)为0.998 8;多抗霉素的最小检出量为1.00×10-9g,在稻田水中的最低检出浓度为0.05 mg/L,在稻田土壤中的最低检出浓度为0.05 mg/kg;在0.06、0.60、1.00 mg/kg加标水平下,多抗霉素在稻田水中的平均加标回收率为97%～99%,相对标准偏差为0.71%～2.4%;在稻田土壤中的平均加标回收率为95%～97%,相对标准偏差为1.7%～4.5%。该方法操作简便,分离效果好,准确度和精密度良好,符合农药残留的检测要求。     

Enantioselective separation of the carfentrazone‐ethyl enantiomers in soil,water and wheat by HPLC

A simple enantioselective HPLC method was developed for measuring carfentrazone‐ethyl enantiomers. The separation and determination was accomplished on an amylose tris[(S)‐α‐methylbenzylcarbamate] (Chiralpak AS) column using n‐hexane/ethanol (98:2, v/v) as mobile phase at a flow rate of 1.0 mL/min with UV detection at 248 nm. The effects of mobile‐phase composition and column temperature on the enantioseparation were discussed. The accuracy, precision, linearity, LODs, and LOQ of the method were also investigated. LOD was 0.001 mg/kg in water, 0.015 mg/kg in soil and wheat, with an LOQ of 0.0025 mg/kg in water and 0.05 mg/kg in soil and wheat for each enantiomer of carfentrazone‐ethyl. SPE was used for the enrichment and cleanup of soil, water, and wheat samples. Recoveries for two enantiomers were 88.4–106.7% with RSD_r of 4.2–9.8% at 0.1, 0.5, and 1 mg/kg levels from soil, 85.8–99.5% with the RSD_r of 4.4?9.6% at 0.005, 0.025, and 0.05 mg/kg levels from water, and from wheat the recoveries were 86.3?91.3% with RSD_r below 5.0% at 0.2, 0.5, and 1 mg/kg levels. This method could be used to identify and quantify the carfentrazone‐ethyl enantiomers in food and environment.     

高效液相色谱法对水果中多菌灵与福美双残留的同时测定

建立了高效液相色谱同时测定水果中多菌灵和福美双残留量的方法。样品经二氯甲烷提取,OasisHLB固相萃取柱净化后,经C18色谱柱分离,甲醇-0.05 mol/L甲酸铵溶液(60∶40,体积比)洗脱,紫外检测器进行检测。结果表明,多菌灵、福美双的的线性范围分别为0.01~10.0、0.05~10.0 mg/kg,相关系数分别为1.0、0.9999,检出限分别为0.005、0.03 mg/kg,平均加标回收率为80%~109%。该方法成功用于市售水果样品的测定。     

高效液相色谱法拆分苯霜灵对映体

以高效液相色谱手性固定相法在对映体水平上建立了苯霜灵的分析方法。采用OD手性色谱柱,正己烷/异丙醇流动相,流速为1.0 mL/m in,检测波长206 nm,以圆二色检测器对两对映体进行出峰顺序确证并考察了其圆二色特性。结果显示,苯霜灵单一对映体在0.52~259.2 mg/L浓度范围内具有较好的线性,线性相关系数均大于0.9994,最低检出限为0.26 mg/L,在240 nm处的出峰顺序为( )/(-)。同时建立了苯霜灵对映体在土壤、水、葡萄中的残留分析方法。土壤和葡萄样品分别用丙酮和乙腈提取,水样用固相萃取法(SPE)富集净化。土壤中两对映体在0.025~2.5 mg/kg范围内的回收率为93.67%~108.95%之间;水样品在0.005~0.5 mg/L浓度范围的回收率在85.13%~100.79%之间,葡萄样品在0.04~1 mg/kg浓度范围的回收率在83.22%~106.62%之间;相对标准偏差RSD均小于6%。     

固相萃取-气相色谱/质谱法分析水果和蔬菜中残留的嘧菌酯

建立了多种水果和蔬菜中嘧菌酯残留的气相色谱/质谱分析方法。首先用乙酸乙酯-环己烷(体积比为1∶1)对样品中的嘧菌酯进行超声波提取,经硅胶固相萃取小柱对样品提取液进行净化、富集,采用气相色谱/质谱法以选择离子监测模式(m/z 344,372,388,403定性,m/z 344定量)进行检测。实验结果表明,嘧菌酯在0.01～1.0 mg/kg浓度范围内呈线性,其相关系数r>0.99。在低、中、高3个添加水平,嘧菌酯的回收率为85.2%～98.2%,相对标准偏差为5.8%～21.5%。方法的检测限不大于0.01 mg/kg,定量限不大于0.05 mg/kg。     

Development and certification of reference materials for residues of organochlorine and organophosphorus pesticides in beef fat ACSL CRM 1 and 2

Beef fat samples were prepared and tested as candidate reference materials for organochlorine and organophosphorus pesticides. The CRMs consisted of beef fat spiked with pesticide solutions. One sample (ACSL CRM 1) was prepared containing close to 0.2 mg/kg of each of the organochlorine pesticides dieldrin and heptachlor epoxide. A second sample (ACSL CRM 2) was prepared containing close to 0.8 mg/kg of each of the organophosphorus pesticides diazinon, chlorpyrifos and ethion. The spiking levels and homogeneity of the materials were verified. The coefficients of variation of 5 analyses carried out to test between-jar homogeneity for each reference material were dieldrin, 3.5%; heptachlor epoxide, 1.1%; diazinon, 2.1%; chlorpyrifos, 1.2% and ethion, 3.1%. No instability in any of these compounds was detected over a twelve month period. The candidate reference materials were found to be suitable for certification by interlaboratory testing. The certification process was based on a two-stage nested design described in ISO Guide 35. Analysis of results reported by collaborating laboratories provided an assessment of the homogeneity of the reference materials. The certified values together with their upper and lower 95% confidence limits are: ACSL CRM 1*Dieldrin*0.199 mg/kg **(0.188, **0.210 mg/kg) *Heptachlor epoxide*0.194 mg/kg **(0.176, **0.212 mg/kg) ACSL CRM 2*Diazinon*0.805 mg/kg **(0.755, **0.855 mg/kg) *Chlorpyrifos*0.790 mg/kg **(0.728, **0.852 mg/kg) *Ethion*0.813 mg/kg **(0.746, **0.879 mg/kg). A certificate for each material was prepared according to the guidelines set out in ISO Guide 31. Received: 25 April 1997 / Revised: 19 August 1997 / Accepted: 28 August 1997     

Development and certification of reference materials for residues of organochlorine and organophosphorus pesticides in beef fat ACSL CRM 1 and 2

Beef fat samples were prepared and tested as candidate reference materials for organochlorine and organophosphorus pesticides. The CRMs consisted of beef fat spiked with pesticide solutions. One sample (ACSL CRM 1) was prepared containing close to 0.2 mg/kg of each of the organochlorine pesticides dieldrin and heptachlor epoxide. A second sample (ACSL CRM 2) was prepared containing close to 0.8 mg/kg of each of the organophosphorus pesticides diazinon, chlorpyrifos and ethion. The spiking levels and homogeneity of the materials were verified. The coefficients of variation of 5 analyses carried out to test between-jar homogeneity for each reference material were dieldrin, 3.5%; heptachlor epoxide, 1.1%; diazinon, 2.1%; chlorpyrifos, 1.2% and ethion, 3.1%. No instability in any of these compounds was detected over a twelve month period. The candidate reference materials were found to be suitable for certification by interlaboratory testing. The certification process was based on a two-stage nested design described in ISO Guide 35. Analysis of results reported by collaborating laboratories provided an assessment of the homogeneity of the reference materials. The certified values together with their upper and lower 95% confidence limits are: ACSL CRM 1*Dieldrin*0.199 mg/kg **(0.188, **0.210 mg/kg) *Heptachlor epoxide*0.194 mg/kg **(0.176, **0.212 mg/kg) ACSL CRM 2*Diazinon*0.805 mg/kg **(0.755, **0.855 mg/kg) *Chlorpyrifos*0.790 mg/kg **(0.728, **0.852 mg/kg) *Ethion*0.813 mg/kg **(0.746, **0.879 mg/kg). A certificate for each material was prepared according to the guidelines set out in ISO Guide 31.     

QuEChERS-高效液相色谱法测定稻田土壤、糙米和秸秆中的灭草松残留

建立了一种稻田土壤、糙米和秸秆中灭草松残留量的QuEChERS-HPLC检测方法。以乙腈为提取溶剂,N-丙基-乙二胺(PSA)为吸附剂,实现样品快速制备;在C18色谱柱上,以甲醇-0.2‰H3PO4(55/45,V/V)为流动相,紫外检测器于215nm波长处检测,在0.1～5.0 mg/L范围内浓度与峰面积呈良好的线性关系,相关系数为0.9991。在添加浓度为0.05～1.0 mg/kg范围内的平均回收率为88.6%～96.8%,相对标准偏差为1.1%～2.7%,检出限为5.5×10-11g。方法能够满足水稻田土壤、糙米和秸秆样品中灭草松的残留检测。     

Determination of chlorpyrifos 20% EC (Dursban 20 EC) in scented rose and its products

The method for determination of chlorpyrifos is validated and dissipation behaviour of residue in scented rose and percent transfer in different products is described. GC-electron-capture detection with a HP-1, 30 m x 0.53 mm, 3.0 microm capillary column and nitrogen at 1 ml/min was used in the study. Plant matrices studied were: leaves, flowers, soil, rose water, absolute and concrete. Detector response linearity and sensitivity, limit of detection and determination, percent recovery were determined based on area response (mm2) of the standard. Analytical field and laboratory samples (rose water by hydro-distillation of the flowers, concrete and absolute by hexane extraction and condensation) were analysed for evaluation of the method. Samples were extracted with acetone, partitioned with water, saturated sodium chloride solution and dichloromethane. The organic layer was rotary-evaporated to 2 ml for cleanup with silica-carbon column. The column was eluted with dichloromethane-toluene-acetone (10:2:2, v/v/v) and the derived solution was rotary-evaporated to 5 ml for end analysis. Matrix enhancement effect was observed for leaf and soil samples for which corrective approach was followed to compensate for overestimation of the residue. Limit of detection for chlorpyrifos standard was 0.05 mg/l with good linearity of detector response (R2 = 0.99). Percent recovery ranged from 78 to 117% in different plant matrices (fortification level 1, 4 and 8 mg/l). Dissipation behaviour showed that chlorpyrifos was below detection limit by the 12th day of application on the scented rose with half life of 3.40 days on leaves and 3.10 days on flowers at 0.1% dosage. Percent transfer studies showed that 5.71, 46.91 and 38.80% of the residue from flowers was transferred to rose water, concrete and absolute, respectively.     

An optical fiber biosensor for chlorpyrifos using a single sol-gel film containing acetylcholinesterase and bromothymol blue

An optical fiber biosensor consisting of acetylcholinesterase (AChE) and bromothymol blue (BTB) doped sol-gel film was employed to detect organophosphate pesticide chlorpyrifos. The main advantage of this optical biosensor is the use of a single sol-gel film with immobilized AChE and BTB. The compatibility of this mixture (AChE and BTB) with the sol-gel matrix has prevented leaching of the film. The immobilization of the enzyme and indicator was simple without chemical modification. The biosensing element on single sol-gel film has been placed inside the flow-cell for flow system. In the presence of a constant AChE, a color change of the BTB and the measured reflected signal at wavelength 622nm could be related to the pesticide concentration in the sample solutions. The performance of optical biosensor in the flow system has been optimized, including chemical and physical parameters. The response time of the biosensor is 8min. A linear calibration curve of chlorpyrifos against the percentage inhibition of AChE was obtained from 0.05 to 2.0mg/L of chlorpyrifos (18-80% inhibition, R(2)=0.9869, n=6). The detection limit for chlorpyrifos was 0.04mg/L. The results of the analysis of 0.5-1.5mg/L of chlorpyrifos using this optical biosensor agreed well with chromatographic method.     

Treatment of the solution extracted from metal contaminated soils by reverse osmosis and chemical precipitation

In this study a process for the remediation of soils contaminated by lead or copper is proposed, consisting of the operations in sequence: soil flushing, membrane treatment, acidification, and metal precipitation. Pb(II) and Cu(II) extraction from a synthetically contaminated soil using a 0.05 M EDTA aqueous solution were investigated in column. The metal removal efficiencies and the final soil metal concentration were 98.2% and 37.96 mg/g respectively for lead and 95.4% and 59.20 mg/kg for copper. The extracted solutions were concentrated through a membrane treatment to reduce the water content up to the 75% and to obtain a permeate metal concentration in compliance with the Italian Environmental Regulation. The recovery of the used EDTA from the retentate solution, with recovery yield of at least 85.4%, was also obtained through acidification. Metal precipitation from the filtered solution was then performed according two different methods, achieving metal removal yield of more than 99.4%.     

气相色谱法测定花生中六六六、滴滴涕、乙草胺和毒死蜱残留

建立了毛细管柱气相色谱法同时测定花生中六六六、滴滴涕、乙草胺和毒死蜱的方法。样品用乙腈提取,固相萃取柱净化,气相色谱仪电子捕获检测器(ECD)进行测定。结果表明,10种农药含量在0.005~1.0 mg/L之间线性关系良好,相关系数均在0.995以上,加标回收率在80.5%~116.9%之间,相对标准偏差在1.2%~5.0%之间。方法适用于花生中六六六、滴滴涕、乙草胺和毒死蜱的同时测定。     

Randomly Methylated β-Cyclodextrins (RAMEB) Enhance the Aerobic Biodegradation of Polychlorinated Biphenyl in Aged-Contaminated Soils

The biological removal of polychlorinated biphenyls (PCBs) from contaminatedsoils is adversely affected by the poor bioavailability of these pollutants. Twodifferent aged-contaminated soils containing about 890 and 8500 mg/kg of PCBswere supplemented with biphenyl and treated in slurry- and solid-phase aerobic0.5 litre-microcosms in the presence of RAMEB at 0, 0.5, 1.0, 3.0% (w/w). RAMEB,which was non-toxic and slowly biodegraded by the soil microorganisms, significantlyenhanced the bioavailability (from 30 to 50%) and the biological degradation (from 15to 55%) and dechlorination of PCBs in both soils and treatment conditions. RAMEBeffects were dependent on the concentration at which it was applied, the soil featuresand the treatment conditions. RAMEB enhanced PCB biodegradation by increasingboth the PCB bioavailability and the availability of biodegrading bacteria in themicrocosms. RAMEB appears a promising bioavailability enhancing agent for thetreatment of PCB-contaminated soils, not only for its positive effects on the PCBsbiodegradation, but also for its biodegradability, non-toxicity and relatively low cost.     

水载流-原子荧光光谱法同时测定土壤中痕量砷、汞

改变原子荧光光谱法以稀酸为载流的进样方式,以水为载流在新型双道原子荧光光谱仪上同时测定了土壤中的痕量砷(As)、汞(Hg).采用王水水浴加热溶解样品,用50 g/L硫脲-抗坏血酸混合溶液预先将砷还原为As(Ⅲ),保持10％(体积分数)以上盐酸浓度,不转移直接定容静置后测定.优化了仪器工作条件,详细考察了以水为载流测定的...     

Simultaneous determination of four fluorescent whitening agents (including trans and cis isomers) in facial mask by dispersive solid‐phase extraction combined with ultra high performance liquid chromatography and diode array detection

A novel ultra high performance liquid chromatography with diode array detection method, based on the dispersive solid‐phase extraction by using polymer weak anion exchange as the sorbent, was established for the simultaneous determination of fluorescent whitening agents 85, 28, 351, and 71 in facial mask. The amounts of polymer weak anion exchange, adsorption time, and volume of elution solvent in the dispersive solid‐phase extraction technology were optimized, and the developed method was validated in terms of the method limit of detection, method limit of quantitation, linear range, recovery, accuracy, and precision. Results indicated that the standard curves were linear over the selected concentration ranges of 0.05–100 mg/L for four target analytes, with determination coefficients greater than 0.999. The method limits of quantitation of the target analytes were in the range of 0.6–2.8 mg/kg. Recoveries were calculated at the concentrations of 1.0–30 mg/kg spiked in negative samples and the values were between 89.3 and 102% with an RSD of 2.5–5.1% for intraday precision and 3.8–5.0% for interday precision. The method was successfully applied to analyze 20 facial mask samples and fluorescent whitening agent 85 was detected in one sample with the concentration of 4.7 mg/kg.