Qualitative aspects and validation of a screening method for pesticides in vegetables and fruits based on liquid chromatography coupled to full scan high resolution (Orbitrap) mass spectrometry

The analytical capabilities of liquid chromatography with single-stage high-resolution mass spectrometry have been investigated with emphasis on qualitative aspects related to selective detection during screening and to identification. The study involved 21 different vegetable and fruit commodities, a screening database of 556 pesticides for evaluation of false positives, and a test set of 130 pesticides spiked to the commodities at 0.01, 0.05, and 0.20 mg/kg for evaluation of false negatives. The final method involved a QuEChERS-based sample preparation (without dSPE clean up) and full scan acquisition using alternating scan events without/with fragmentation, at a resolving power of 50,000. Analyte detection was based on extraction of the exact mass (±5 ppm) of the major adduct ion at the database retention time ±30 s and the presence of a second diagnostic ion. Various options for the additional ion were investigated and compared (other adduct ions, M + 1 or M + 2 isotopes, fragments). The two-ion approach for selective detection of the pesticides in the full scan data was compared with two alternative approaches based on response thresholds. Using the two-ion approach, the number of false positives out of 11,676 pesticide/commodity combinations targeted was 36 (0.3 %). The percentage of false negatives, assessed for 2,730 pesticide/commodity combinations, was 13 %, 3 %, and 1 % at the 0.01-, 0.05-, and 0.20-mg/kg level, respectively (slightly higher with fully automated detection). Following the SANCO/12495/2011 protocol for validation of screening methods, the screening detection limit was determined for 130 pesticides and found to be 0.01, 0.05, and ≥0.20 mg/kg for 86, 30, and 14 pesticides, respectively. For the detected pesticides in the spiked samples, the ability for unambiguous identification according to EU criteria was evaluated. A proposal for adaption of the criteria was made.     

Determination of neonicotinoid pesticides residues in agricultural samples by solid-phase extraction combined with liquid chromatography-tandem mass spectrometry

This work reports a new sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, confirmation and quantification of six neonicotinoid pesticides (dinotefuran, thiamethoxam, clothiandin, imidacloprid, acetamiprid and thiacloprid) in agricultural samples (chestnut, shallot, ginger and tea). Activated carbon and HLB solid-phase extraction cartridges were used for cleaning up the extracts. Analysis is performed by LC-MS/MS operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Quantification was carried by the internal standard method with D(4)-labeled imidacloprid. The method showed excellent linearity (R(2)≥0.9991) and precision (relative standard deviation, RSD≤8.6%) for all compounds. Limits of quantification (LOQs) were 0.01 mg kg(-1) for chestnut, shallot, ginger sample and 0.02 mg kg(-1) for tea sample. The average recoveries, measured at three concentrations levels (0.01 mg kg(-1), 0.02 mg kg(-1) and 0.1 mg kg(-1) for chestnut, shallot, ginger sample, 0.02 mg kg(-1), 0.04 mg kg(-1) and 0.2 mg kg(-1) for tea sample), were in the range 82.1-108.5%. The method was satisfactorily validated for the analysis of 150 agricultural samples (chestnut, shallot, ginger and tea). Imidacloprid and acetamiprid were detected at concentration levels ranging from 0.05 to 3.6 mg kg(-1).     

Exact-mass library for pesticides using a molecular-feature database

An automated molecular-feature database (MFD) consisting of the exact monoisotopic mass of 100 compounds, at least one exact mass product ion for each compound, and chromatographic retention time were used to identify pesticides in food and water samples. The MFD software compiles a list of accurate mass ions, excludes noise, and compares them with the monoisotopic exact masses in the database. The screening criteria consisted of +/-5 ppm accurate mass window, +/-0.2 min retention time window, and a minimum 1000 counts (signal-to-noise (S/N) ratio of approximately 10:1). The limit of detection for 100 tested compounds varied from <0.01 mg/kg for 72% of the compounds to <0.1 mg/kg for 95% of the compounds. The MFD search was useful for rapid screening and identification of pesticides in food and water, as shown in actual samples. The combined use of accurate mass and chromatographic retention time eliminated false positives in the automated analysis. The major weakness of the MFD is matrix interferences and loss of mass accuracy. Strengths of the MFD include rapid screening of 100 compounds at sensitive levels compared with a manual approach and the ease of use of the library for any accurate mass spectrometer instrumentation capable of routine sub-5-ppm mass accuracy.     

Multiresidue determination of pesticides by solid-phase extraction and GC-MS for control of peach production in Bulgaria

A multiresidue analytical method based on acetone extraction and clean-up/pre-concentration on polymeric sorbents was validated for 42 pesticides in peach matrix in order to control safety of fresh production on the Bulgarian market. Matrix-matched calibration was used by addition of pesticides just before SPE. In this way the standards and the samples undergo exactly the same procedure and an improvement of recoveries for the target analytes was observed. The identification and quantification were done by gas chromatographic technique with mass-spectrometric detection (GC-MS). The limits of detection obtained were 0.005?mg?kg^–1 or lower for the most of analytes, and the recovery data were in range 73–109% at three spiked levels 0.01, 0.1 and 0.2?mg?kg^?1. The validated method was used for monitoring of selected pesticides in fresh peach fruits home production. Approximately 30% of the analysed lots (total 33 samples) contained residues mainly of cypermethrin and procymidone, but did not exceed EU MRLs.     

凝胶渗透色谱净化-气相色谱/串联质谱分析蘑菇中的36种农药残留

建立了用凝胶渗透色谱净化-气相色谱/串联质谱分析蘑菇中36种农药残留的方法。蘑菇中的待测农药组分在30 ℃条件下用乙酸乙酯提取,高速匀浆后通过凝胶渗透色谱净化;选用填料为中性多孔的聚苯乙烯二乙烯基苯微球体的S-X3玻璃柱(22 g,19 cm×2 cm)作为凝胶渗透色谱净化柱,流动相为乙酸乙酯-环己烷(体积比为1∶1)溶液,流速5 mL/min;收集第7~15 min流出的液体用气相色谱-三重四极杆串联质谱仪测定。在0.01~1.0 mg/L的质量浓度范围内,各种农药标准溶液的线性相关系数均大于0.99。在样品中添加36种农药(添加水平为0.01,0.05,0.10 mg/kg)的混合标准溶液,平均回收率为72.6%~117.1%,相对标准偏差为2.0%~10.8%(n=5),最低检出限为 0.1~0.7 μg/kg,最低定量限为 0.2~2 μg/kg。     

Method validation of resistive heating--gas chromatography with flame photometric detection for the rapid screening of organophosphorus pesticides in fruit and vegetables

A rapid method for the screening of organophosphorus (OP) pesticides in fruit and vegetables is reported. Sample extracts were analysed using resistive heating-gas chromatography (RH-GC) with flame photometric detection (FPD). A CarboFrit insert in the GC liner allowed injection of crude extracts onto the GC system. Separation of up to 20 pesticides was achieved in 4.3 min with excellent retention time stability. Signal-to-noise ratios of 5:1 or better were obtained for the majority of the pesticides at the lowest calibrated level (LCL), 0.01 microg ml(-1), with excellent linearity over the range 0.01-0.5 microg ml(-1) (0.004-0.2 mg kg(-1) equivalent). Average recoveries between 70 and 116% were obtained for pesticides spiked at 0.01 and 0.1 mg kg(-1) with associated R.S.D. values < or =20% in the majority of cases. Estimates of relative reproducibility standard deviation (R.S.D.(R)), made by combining observed R.S.D. values with estimates of uncertainty associated with mean recovery allowed the determination of HORRAT values which confirmed that the method is capable of producing results which are fit for purpose. The validated method was then used to screen peaches, grapes and sweet peppers for a total of 37 pesticides. Incurred residue results obtained using RH-GC-FPD were in good agreement with the results from analysis of the same samples using MS confirmation.     

Comprehensive multi-residue method for the target analysis of pesticides in crops using liquid chromatography-tandem mass spectrometry

A liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) multi-residue method for the simultaneous target analysis of a wide range of pesticides and metabolites in fruit, vegetables and cereals has been developed. Gradient elution has been used in conjunction with positive mode electrospray ionization tandem mass spectrometry to detect up to 171 pesticides and/or metabolites in different crop matrices using a single chromatographic run. Pesticide residues were extracted/partitioned from the samples with acetone/dichloromethane/light petroleum. The analytical performance was demonstrated by the analysis of extracts from lettuce, orange, apple, cabbage, grape and wheat flour, spiked at three concentration levels ranging from 0.01 to 0.10 mg/kg for each pesticide and/or metabolite. In general, recoveries ranging from 70 to 110%, with relative standard deviations better than 15%, were obtained. The recovery and repeatability data are in good accordance with EU guidelines for pesticide residue analysis. The limit of quantification for all targeted pesticides and metabolites tested was 0.01 mg/kg. The selectivity and robustness of the LC-MS/MS method was demonstrated by a 1-year comparison of its analytical results with those obtained from our validated GC and LC multi-residue methods applied to more than 3500 routine samples. The validated LC-MS/MS method has been implemented in our analytical scheme since 2004, replacing four of the conventional detection methods, i.e. GC-flame-photometric detection (acephate, methamidophos, etc.), GC-nitrogen-phosphorus detection, LC-UV detection (carbendazim, thiabendazole, imazalil and prochloraz) and LC-fluorescence detection (N-methylcarbamate pesticides). During a 3-year period, the LC-MS/MS method has been applied to the analyses of more than 12,000 samples.     

High-performance liquid chromatographic determination of benzoylurea insecticides residues in grapes and wine using liquid and solid-phase extraction

A method for the determination of the benzoylurea insecticides diflubenzuron, triflumuron, teflubenzuron, lufenuron and flufenoxuron in grapes and wine by HPLC has been developed and validated. Grape samples (50 g) were homogenized and extracted with ethyl acetate-sodium sulfate and further cleaned-up by solid-phase extraction on silica sorbent. Wine samples (10 ml) diluted with water (1:3) were solid-phase extracted on an octadecyl sorbent using methanol as the eluent. The pesticides were separated on a reversed-phase octadecyl narrow-bore column by gradient elution and the residues were determined with a UV diode array detector. The calibration plots were linear over the range 0.05-5 micrograms/ml. Recoveries of benzoylurea pesticides from spiked grapes (0.02-2.0 mg/kg) and wine (0.01-0.2 mg/l) were 85.8-101.6% and 69.1-104.8%, respectively, and the limits of quantification for these insecticides were < 0.01 mg/kg for grapes and < 0.01 mg/l for wine. The method was applied to the determination of flufenoxuron and teflubenzuron residues in grapes from treated fields and in produced wine.     

应用超高效液相色谱-四极杆-飞行时间质谱建立茶叶中农药残留的筛查与确证方法

基于超高效液相色谱-四极杆-飞行时间质谱(UPLC-QTOF-MS),使用UNIFI软件建立91种农药残留的筛查与确证方法,进行定性方法验证并应用于流通市场中茶叶的筛查检测。通过对收集的农药认证标准物质(CRM)分析,构建91种农药化合物的质谱数据库。样品经乙腈提取,固相萃取柱净化,Acquity BEH C18色谱柱分离,在MS^E模式下进行全信息采集(ESI+), UNIFI软件对数据进行匹配分析。设置保留时间最大偏差为±0.1 min,精确质量偏差阈值为±5×10^-6,可识别加合物形式包括[M+H]⁺、[M+Na]⁺、[M+K]⁺、[M+NH₄]⁺。参照SANTE/11813/2017指南进行定性方法学验证。在21份茶叶样品中添加混合标准溶液至4个水平(0.01、0.05、0.10、0.20 mg/kg),确定每种农药在茶叶样品中的筛查检出限(SDL),共评估了1911种农药/样品组合。发现有66种农药的SDL为0.01 mg/kg, 8种农药的SDL为0.05 mg/kg, 1种农药的SDL为0.10 mg/kg, 3种农药的SDL为0.20 mg/kg,共有13种农药的SDL大于0.20 mg/kg。一种农药在筛查检测中存在基质抑制效应。最后,应用建立的方法分析了流通市场中22份茶叶样品的农药残留情况,从6份茶叶样品中筛查检测出6种农药化合物,经人工鉴定均为阳性。该法为茶叶中农药残留的高通量筛查检测提供了参考。     

A multiresidue method for the determination of 109 pesticides in rice using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) sample preparation method and gas chromatography/mass spectrometry with temperature control and vacuum concentration

A rapid, specific and sensitive multiresidue method based on the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) sample preparation method and gas chromatography with mass spectrometric detection by selected ion monitoring (GC/MS-SIM) has been developed for the routine analysis of 109 pesticides in rice. The method uses one quantification ion and two identification ions. Temperature control during sample preparation helps improve the recovery of thermally labile pesticides such as captan. The method was validated by the analysis of samples spiked at 0.025-0.150 mg/kg in rice matrix. The recoveries of all pesticides were between 80% and 115% with a relative standard deviation of less than 15%. The limit of quantitation (LOQ) for most compounds met the maximum residue limits (MRLs) for pesticides in rice in Korea.     

气质联机分析蔬菜中农药多残留及基质效应的补偿

摘要建立了蔬菜中52种农药化合物的气相色谱\|质谱检测方法, 考察了基质效应和分析保护剂在方法中的应用, 评价了3种分析保护剂组合的加入对补偿基质效应的影响, 确定了最佳配比. 样品前处理采用乙腈提取, 用PSA(Primary-secondary amine)固相材料分散净化技术, 用气质联机在选择离子监测模式下分析检测. 该方法在0.01～1.00 mg/L范围内线性关系良好, 相关系数大于0.98, 最低检测浓度除溴氰菊酯和异菌脲外均在0.2～9.4 mg/kg之间, 各化合物添加回收率为81.8%～119.5%, 相对标准偏差为0.8%～17.6%.     

Determination of pesticide residues in coconut water by liquid-liquid extraction and gas chromatography with electron-capture plus thermionic specific detection and solid-phase extraction and high-performance liquid chromatography with ultraviolet detection

Two simple methods were developed to determine 11 pesticides in coconut water, a natural isotonic drink rich in salts, sugars and vitamins consumed by the people and athletes. The first procedure involves solid-phase extraction using Sep-Pak Vac C18 disposable cartridges with methanol for elution. Isocratic analysis was carried out by means of high-performance liquid chromatography with ultraviolet detection at 254 nm to analyse captan, chlorothalonil, carbendazim, lufenuron and diafenthiuron. The other procedure is based on liquid-liquid extraction with hexane-dichloromethane (1:1, v/v), followed by gas chromatographic analysis with effluent splitting to electron-capture detection for determination of endosulfan, captan, tetradifon and trichlorfon and thermionic specific detection for determination of malathion, parathion-methyl and monocrotophos. The methods were validated with fortified samples at different concentration levels (0.01-12.0 mg/kg). Average recoveries ranged from 75 to 104% with relative standard deviations between 1.4 and 11.5%. Each recovery analysis was repeated at least five times. Limits of detection ranged from 0.002 to 2.0 mg/kg. The analytical procedures were applied to 15 samples and no detectable amounts of the pesticides were found in any samples under the conditions described.     

Evaluation of relevant time-of-flight-MS parameters used in HPLC/MS full-scan screening methods for pesticide residues

An automatic screening method based on HPLC/time-of-flight (TOF)-MS (full scan) was used for the analysis of 103 non-European fruit and vegetable samples after extraction by the quick, easy, cheap, effective, rugged, and safe method. The screening method uses a database that includes 300 pesticides, their fragments, and isotopical signals (910 ions) that identified 210 pesticides in 78 positive samples, with the highest number of detection being nine pesticides/sample. The concentrations of 97 pesticides were <10 microg/kg, 53 were between 10 and 100 microg/kg, and 60 were at a concentration of >100 microg/kg. Several parameters of the automatic screening method were carefully studied to avoid false positives and negatives in the studied samples; these included peak filter (number of chromatographic peak counts) and search criteria (retention time and error window). These parameters were affected by differences in mass accuracy and sensitivity of the two HPLC/TOF-MS systems used with different resolution powers (15 000 and 7500), the capabilities of which for resolving the ions included in the database from the matrix ions were studied in four matrixes, viz., pepper, rice, garlic, and cauliflower. Both of these mass resolutions were found to be satisfactory to resolve interferences from the signals of interest in the studied matrixes.     

Analysis of pesticide residues using the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) pesticide multiresidue method in combination with gas and liquid chromatography and tandem mass spectrometric detection

The Quick Easy Cheap Effective Rugged and Safe multiresidue method (QuEChERS) has been validated for the extraction of 80 pesticides belonging to various chemical classes from various types of representative commodities with low lipid contents. A mixture of 38 pesticides amenable to gas chromatography (GC) were quantitatively recovered from spiked lemon, raisins, wheat flour and cucumber, and determined using gas chromatography-tandem mass spectrometry (GC-MS/MS). An additional mixture of 42 pesticides were recovered from oranges, red wine, red grapes, raisins and wheat flour, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination. The pesticides chosen for this study included many of the most frequently detected ones and/or those that are most often found to violate the maximum residue limit (MRL) in food samples, some compounds that have only recently been introduced, as well as a few other miscellaneous compounds. The method employed involved initial extraction in a water/acetonitrile system, an extraction/partitioning step after the addition of salt, and a cleanup step utilizing dispersive solid-phase extraction (D-SPE); this combination ensured that it was a rapid, simple and cost-effective procedure. The spiking levels for the recovery experiments were 0.005, 0.01, 0.02 and 0.2 mg kg(-1) for GC-MS/MS analyses, and 0.01 and 0.1 mg kg(-1) for LC-MS/MS analyses. Adequate pesticide quantification and identity confirmation were attained, even at the lowest concentration levels, considering the high signal-to-noise ratios, the very good accuracies and precisions, as well as the good matches between the observed ion ratios. Mean recoveries mostly ranged between 70 and 110% (98% on average), and relative standard deviations (RSD) were generally below 10% (4.3% on average). The use of analyte protectants during GC analysis was demonstrated to provide a good alternative to the use of matrix-matched standards to minimize matrix-effect-related errors. Based on these results, the methodology has been proven to be highly efficient and robust and thus suitable for monitoring the MRL compliance of a wide range of commodity/pesticide combinations.     

QuEChERS-气相色谱/串联质谱法同时测定杨桃中37种农药残留

建立了QuEChERS-气相色谱/三重四极杆串联质谱(GC-MS/MS)测定杨桃中37种农药残留量的方法.样品以1％乙酸乙腈为提取溶剂,采用QuEChERS净化,在质谱多反应监测(MRM)模式下进行定性,基质匹配标准曲线外标法定量.结果表明:在0.01～0.5 mg/L范围内,37种农药的线性关系良好,方法定量限均低于0.01 mg/kg;在低、中、高3个添加水平范围内平均回收率在72.9％～117％之间,相对标准偏差(RSD)≤9.6％.该方法简单、快速、溶剂用量少、灵敏度高,适用于分析杨桃样品中37种农药残留量的检测和确证.     

Multiresidue determination of organophosphorus pesticides in ginkgo leaves by accelerated solvent extraction and gas chromatography with flame photometric detection

A rapid and simple method using accelerated solvent extraction and solid-phase extraction cleanup was developed and validated for the determination of 15 organophosphorus pesticides in ginkgo leaves by capillary gas chromatography with flame photometric detection. The pesticides were extracted at 100 degrees C under 1500 psi pressure in <20 min. The average recovery from 10 g ginkgo leaves, fortified at 3 levels ranging from 0.05 to 1.00 mg/kg, was 95.2% with a relative standard deviation of 4.6%. The limits of detection ranged from 1.11 x 10(-3) mg/kg (dimethoate) to 4.44 x 10(-3) mg/kg (dichlorvos). The proposed method showed acceptable accuracy and precision while minimizing environmental concerns, time, and labor. Furthermore, the method could be easily applied to the monitoring of these 15 organophosphorus pesticides in ginkgo leaves.     

Dispersive solid-phase extraction cleanup combined with accelerated solvent extraction for the determination of carbamate pesticide residues in Radix Glycyrrhizae samples by UPLC-MS-MS

Dispersive solid-phase extraction (DSPE) cleanup combined with accelerated solvent extraction (ASE) is described here as a new approach for the extraction of carbamate pesticides in Radix Glycyrrhizae samples prior to UPLC-MS-MS. In the DSPE-ASE method, 15 carbamate pesticides were extracted from Radix Glycyrrhizae samples with acetonitrile by the ASE method at 60 °C with a 5 min heating time and two static cycles. Cleanup of a 1 mL aliquot of the extract by the DSPE method used 20 mg PSA (primary secondary amine), 50 mg Al(2)O(3)-N, and 20 mg GCB (graphitized carbon black) (as cleanup sorbents) under the determined optimum conditions. The linearity of the method was in the range of 10 to 200 ng/mL with correlation coefficients (r(2)) of more than 0.996. The limits of detection were approximately 0.2 to 5.0 μg/kg. The method was successfully used for the analysis of target pesticides in Radix Glycyrrhizae samples. The recoveries of the carbamate pesticides at the spiking levels of 50, 100, and 200 μg/kg ranged from 79.7% to 99.3% with relative standard deviations lower than 10%. This multi-residue analytical method allows for a rapid, efficient, sensitive and reliable determination of target pesticides in Radix Glycyrrhizae and other medicinal herbs.     

Development of a multi-residue screening method for the determination of pesticides in cereals and dry animal feed using gas chromatography-triple quadrupole tandem mass spectrometry

A multi-residue screening method for simultaneous analysis of 122 gas chromatography amenable pesticides in dry matrices such as cereal grain and certain feedingstuffs was developed. The method entails a simple extraction of re-hydrated sample with acetonitrile followed by a dispersive solid phase extraction (dispersive-SPE) clean-up step prior to the final determination by gas chromatography/triple quadrupole tandem mass spectrometry (GC-MS/MS). Due to complexity of analyzed matrices, two MS/MS transitions were set for each pesticide to eliminate the need for re-analysis of potentially positive samples, and provide unequivocal identification of detected pesticides in accordance with recent guidelines, in a single analytical run. Thus, in the developed GC-MS/MS acquisition method, a total of 216 different multiple reactions monitoring (MRM) transitions were monitored in one set of experimental conditions. To evaluate performance of the method, validation experiments were carried out on wheat grain at three spiking levels (0.01, 0.02 and 0.05 mg kg(-1)). Additional recovery tests at 0.05 mg kg(-1) were carried out on several other matrices. The recoveries ranged between 73 and 129% with associated relative standard deviations between 1 and 29% for the majority of pesticides. Limits of detection were less or equal to 0.01 mg kg(-1) for approximately 68% of pesticides. The applicability of the proposed method to detect and quantify pesticide residues has been demonstrated in the analysis of 136 real samples. Additionally, the method was favorably compared with an acetone extraction method (accepted as a reference method by some of European and U.S. authorities) in the analysis of real samples known to contain pesticide residues.     

Liquid chromatography-electrospray mass spectrometry multi-residue determination of pesticides in apples and pears

This paper describes a rapid, specific and sensitive multi-residue method for the routine quantitative analysis of pesticides of several classes used for the treatment of apples and pears, down to their respective maximum residue limits (MRLs). It involves a rapid extraction procedure and liquid chromatography coupled to electrospray mass selective detection. Seven pesticides were extracted at pH 4.5 with a mixture of acetone-dichloromethane-hexane (50:20:30, v/v/v). Ionization was performed at atmospheric pressure in an electrospray-type source and detection was carried out using the selected ion monitoring (SIM) mode. Extraction recoveries were between 55 and 98% except for methylthiophanate (< 20%). Limits of detection (LODs) and limits of quantitation (LOQs) ranged, respectively, from 0.01 to 0.02 mg/kg and from 0.02 to 0.05 mg/kg, with relative standard deviation (R.S.D.) less than 19%. An excellent linearity was observed for LOQs up to 5 mg/kg. Intermediate ("inter-assay") precision and accuracy were satisfactory. The method was applied to many fruit samples intended for commercialization.     

固相萃取–气相色谱–串联质谱法测定茶叶中9种农药残留量

建立固相萃取净化–气相色谱–串联质谱法同时测定茶叶中9种农药残留量的方法。茶叶样品用乙腈均质提取,提取液经固相萃取净化处理后,采用DB–5MS毛细管色谱柱分离,在多反应监测模式下测定,外标法定量。9种农药组分的质量浓度在0.01~0.50 mg/L范围内与其色谱峰面积呈良好线性,相关系数r~2大于0.998,方法测定下限(10 S/N)为0.002~0.01 mg/kg。以空白绿茶、红茶、普洱茶和乌龙茶为基体,在0.05,0.1,0.2 mg/kg 3个添加水平进行加标回收试验,加标回收率在73.6%~99.7%之间,相对标准偏差为4.2%~8.7%(n=6)。该法操作简便、快速,适用于茶叶中多种农药残留的测定。