QuEChERS-分散液液微萃取/气相色谱-串联质谱法高通量快速检测蔬果中152种农药残留

曹小云，陈树干，曾楚莹，黎秀娟，王 露

(广东省深圳市盐田区疾病预防控制中心，广东 深圳 518081)

农产品中农药多残留是食品安全中最令人关注的问题之一[1]，由于其对人体的长期健康风险[2-3]，国际食品法典委员会(CAC)和多数国家均制定了严格的农产品中农药最高残留限量(MRLs)[4]，日本、欧盟等发达国家对未设MRLs的农药，一般均要求其含量小于0.01 mg/kg。我国《GB2763-2016食品中农药最大残留限量》[5]已对433种农药制定了4 140项标准，但仍与发达国家有差距[4]，蔬果中农药残留情况依然严峻[6]。因此，亟待建立新鲜蔬果中高灵敏度、高准确性和高通量的检测农药残留的分析方法。

由于新鲜蔬果的基质非常复杂，对其进行农残检测时需繁琐的样品前处理以减少干扰。随着科学技术的发展，特别是气相色谱-质谱法(GC-MS)[7-8]、气相色谱-串联质谱法(GC-MS/MS)[9-10]、超高效液相色谱-串联质谱法(LC-MS/MS)[11]等联用技术的发展，将色谱高效的分离性能与质谱优越的抗干扰、高灵敏度、高通量离子监测能力相结合，能够在复杂基质背景下实现目标物的准确测定，从而可以摒弃繁杂、污染大、不经济的传统前处理方法，而采用分散固相萃取(DSPE)、QuEChERS法、液相微萃取(LPME或LLME)等[12-13]新技术。如GB 23200.113-2018[14]采用QuEChERS法，使用特定吸附填料吸附除去杂质，净化萃取液[9]；Rezaee等[15]发展的分散液液微萃取法(DLLME)，用微量有机溶剂即可实现目标物的提取和富集[13,16]，操作简便、成本低、快速、环保、效果好。然而每种方法都有各自的优缺点，如QuEChERS法在浓缩痕量残留农药的同时也浓缩了杂质，需根据不同样品优选净化吸附剂及用量[12,14]；DLLME法则只适用于水样等基质简单的样品，难以直接应用于基质复杂的食品中[7,13]。虽然通过方法联用则可发挥各自优势互补不足，但将QuEChERS和DLLME及GC-MS/MS三者联合应用的报道较少[8,13]，且涉及的农药种类较少。本研究将QuEChERS和DLLME及GC-MS/MS 3种技术联用，并通过实验条件优化，建立了同时检测新鲜蔬果中152种(含异构体)农药残留的分析方法，以满足新鲜蔬菜水果中农药多残留的高通量快速筛查及应急检测需要。

1 实验部分

1.1 仪器与试剂

Trace1300 TSQ8000 Evo气相色谱-质谱仪(美国ThermoFisher公司)；Allegra 64R Centrifuge高速冷冻离心机(美国BeckmanCoulter公司)；GENIUS 3 VORTEX漩涡混合器、A11分析研磨机(德国IKA公司)。

乙腈、丙酮、二氯甲烷、乙酸乙酯(优级纯，德国Merck公司);三氯甲烷和氯化钠(分析纯，上海凌峰化学试剂有限公司)：QuEChERS提取盐由2 g 无水MgSO4、0.5 g NaCl、0.5 g柠檬酸三钠二水合物、0.25 g柠檬酸氢二钠组成，净化剂由300 mg无水MgSO4、50 mg乙二胺-N-丙基硅烷(PSA)和5 mg石墨化碳黑(GCB)组成，均购于美国ThermoFisher公司。

农药标准物质：有机磷类、有机氯类、氨基甲酸酯类、菊酯类、除草剂、杀菌剂等农药及其异构体共152种(日本林纯药、美国O2si smart solutions和德国Dr.Ehrenstorfer)。标准工作溶液：将各农药标准品用丙酮稀释成质量浓度10.0 mg/L的标准储备液，临用前再用乙腈混合逐级稀释成低浓度混合标准工作溶液；用空白基质溶液配制用于绘制校准曲线的标准溶液。

1.2 样品前处理

取蔬果新鲜样品100 g用研磨机研磨成匀浆，搅拌均匀后称取5.0 g于50 mL离心管中(剩余匀浆于-20 ℃冰箱中储存备用)，加入5.0 mL乙腈，于-20 ℃冷冻10 min，再加入提取盐，涡旋1 min后以9 000 r/min离心5 min，吸取2.0 mL上清液于15 mL离心管(预先加入净化剂)中；再涡旋离心1次，取1.0 mL上清液于15 mL离心管，准确加入50 μL三氯甲烷萃取剂，再加4 mL纯水，涡旋离心后用微量注射器取管底部液滴至含有内衬管的进样瓶中，GC-MS/MS自动进样测定。

1.3 色谱-质谱条件

色谱条件：色谱柱TG-5MS(30 m×0.25 μm×0.25 mm)；进样口温度280 ℃；柱箱升温程序：初始柱温60 ℃，保持2 min，以25 ℃/min升至180 ℃，再以5 ℃/min升至280 ℃，最后以10 ℃/min升温至300 ℃，保持5 min；不分流进样，进样量1.0 μL；氦气柱流量1.20 mL/min。

质谱条件：电子轰击电离源(EI)温度300 ℃；传输线温度280 ℃；选择反应监测扫描(SRM)模式；根据农药各组分保留时间分段扫描，窗带宽(Window)为1.2 min，循环时间0.3 s，其余参数用仪器默认值；152种农药的保留时间、离子对信息和碰撞能见表1。

表1 152种农药的保留时间、离子对信息和碰撞能Table 1 Retention times,ion pairs information and collision energy of 152 pesticides

(续表1)

No.CompoundRetentiontime/minIonpairs(m/z)Collisionenergy(eV)60Cyprodinil(嘧菌环胺)14.79224.1>196.9∗,224.1>208.0,225.1>209.720,18,1661Chlorfenvinphos-E-trans(E-反式毒虫畏)14.87266.9>159.0∗,268.8>161.0,322.9>267.014,12,1262Dimethametryn(异戊乙净)14.97212.1>68.1∗,212.1>94.1,212.1>122.130,20,1263Heptachlorepoxide(环氧七氯)15.06262.9>192.9∗,352.8>262.9,354.7>264.930,16,1264Oxychlordane(氧化氯丹)15.08115.0>50.9∗,184.9>84.9,184.9>121.022,26,1265Trichlorfon(敌百虫)15.2292.9>65.0∗,109.0>63.0,109.0>81.06,10,666Isofenphos(异丙胺磷)15.22185.0>121.0∗,213.0>121.0,213.0>185.010,14,667Chlorfenvinphos-Z-cis(Z-顺式毒虫畏)15.22266.9>159.0∗,294.9>267.0,323.0>267.014,8,1268Isocarbophos(水胺硫磷)15.22121.1>65.0∗,136.0>69.0,136.0>108.014,30,1269Isofenphos-methyl(甲基异丙胺磷)15.23199.0>65.0∗,199.0>121.0,241.1>121.134,10,2070Esprocarb(禾草畏)15.3291.0>65.0∗,119.0>65.0,119.0>91.016,26,1071Dimepiperate(哌草丹)15.32119.0>65.0∗,119.0>91.1,145.0>112.126,10,872Phoxim(辛硫磷)15.33135.2>77.1∗,135.2>94.0,135.2>134.514,8,673Quinalphos(喹硫磷)15.33146.0>118.1∗,157.1>102.0,157.1>129.010,22,1474Phenthoate(杀虫杀螨剂)15.33121.0>77.0∗,246.0>121.0,274.0>121.022,8,1075Methidathion(杀扑磷)15.76145.0>58.0∗,145.0>85.0,302.6>284.914,6,1476Propaphos(丙虫磷)15.77139.9>125.0∗,220.0>125.0,220.0>140.012,24,1077α-cis-Chlordane(α-顺式氯丹)15.77372.8>265.8∗,374.7>265.8,376.6>268.020,20,2078o,p′-DDE(o,p′-滴滴伊)15.90246.0>176.1∗,317.8>246.0,317.8>248.028,20,1879Fenothiocarb(苯硫威)15.9172.1>56.0∗,105.7>72.0,160.1>72.112,10,1080Paclobutrazol(多效唑)15.95125.0>89.0∗,236.0>125.0,236.0>167.018,12,1081Pentachlorobiphenyl1(PCB101,五氯联苯峰1)15.95253.9>184.0∗,323.8>253.9,325.8>255.930,25,2582Tetrachlorvinphos(杀虫畏)16.07109.0>79.0∗,328.9>109.0,330.8>109.06,18,1883Endosulfan1(硫丹峰1)16.15194.7>125.0∗,194.7>159.4,240.6>205.922,8,1484γ-trans-Chlordane(γ-反式-氯丹)16.23271.7>236.8∗,372.7>263.7,374.7>265.912,20,2285Fenamiphos(克线磷)16.42154.0>139.0∗,216.9>202.0,303.1>195.210,12,886Butamifos(丁胺磷)16.46200.0>65.1∗,286.0>185.0,286.0>202.020,24,1487Napropamide(敌草胺)16.48100.1>72.1∗,128.2>72.1,271.1>72.16,6,1488Prothiofos(丙硫磷)16.65266.7>220.9∗,266.7>238.9,308.9>239.018,8,1489Metominostrobin-E(E-苯氧菌胺)16.73191.0>119.0∗,191.0>132.6,191.0>160.120,18,1090Profenofos(丙溴磷)16.75296.7>268.9∗,336.9>266.9,336.9>308.910,12,891Pretilachlor(丙草胺)16.83202.1>145.5∗,202.1>174.2,238.1>146.114,8,1092Butachlor(丁草胺)16.84160.0>131.7∗,176.1>146.9,188.1>160.112,12,1093p,p′-DDE(p,p′-滴滴伊)16.88246.0>176.1∗,317.8>246.0,317.8>248.028,20,1894Dieldrin(狄氏剂)16.95262.8>190.9∗,262.8>192.9,262.8>227.830,30,1695p,p′-DDD(p,p′-滴滴滴)17.16235.0>165.1∗,235.0>199.0,236.8>165.020,14,2096Flusilazole(氟硅唑)17.22206.0>151.3∗,233.0>151.9,233.0>164.914,14,1697Cyproconazole(环唑醇)17.62222.0>82.1∗,222.0>89.3,222.0>125.010,38,2098Endrin(异狄氏剂)17.65245.0>173.0∗,262.8>192.9,280.8>245.322,30,899Fenoxanil(稻瘟酰胺)17.76189.0>125.1∗,293.1>155.0,293.1>198.012,20,12100Chlorobenzilate(杀螨酯)17.93111.0>75.1∗,139.0>74.9,139.0>111.014,26,12101Endosulfan2(硫丹峰2)17.96158.9>123.0∗,194.7>159.0,240.6>205.812,8,12102Fensulfothion(芬硫磷)18.04307.9>96.9∗,307.9>153.1,307.9>293.026,12,8103o,p′-DDD(o,p′-滴滴滴)18.25235.0>165.1∗,235.0>199.0,236.8>165.020,14,20104o,p′-DDT(o,p′-滴滴涕)18.33235.0>165.1∗,235.0>199.5,236.8>165.022,10,22105Ethion(乙硫磷)18.36153.0>97.0∗,230.9>128.9,230.9>174.910,22,12106Nonachlor-trans(反式九氯)18.38236.8>142.9∗,262.8>192.9,408.7>300.024,28,18107Endrinaldehyde(乙醛异狄氏剂)18.57173.0>138.1∗,249.8>214.9,344.9>281.016,24,8108Hexachlorobiphenyl1(PCB138,六氯联苯峰1)18.64289.9>218.0∗,357.9>287.8,359.8>289.830,25,25109Mepronil(担菌宁)18.66119.0>65.0∗,119.0>91.0,269.1>119.122,12,14110Triazophos(三唑磷)18.80161.0>105.7∗,161.0>134.1,172.1>77.112,8,25111Benalaxyl(苯霜灵)19.1491.0>65.0∗,148.1>77.0,148.1>79.012,30,22112Carfentrazon-ethyl(唑草酮)19.18290.0>99.9∗,311.9>150.7,340.1>312.136,18,10113Edifenphos(克瘟散)19.20172.9>65.1∗,172.9>109.0,310.0>109.030,8,26114Propiconazole1(丙环唑峰1)19.31172.9>74.0∗,172.9>109.0,172.9>145.038,26,16115Endosulfansulfate(硫丹硫酸盐)19.34238.7>203.9∗,271.7>234.9,271.7>236.812,12,12116p,p′-DDT(p,p′-滴滴涕)19.46235.0>165.1∗,235.0>199.5,236.8>165.022,10,22117Propiconazole2(丙环唑峰2)19.53172.9>74.0∗,172.9>109.0,172.9>145.038,24,14118Hexachlorobiphenyl(PCB153,六氯联苯)19.53287.8>217.9∗,357.7>287.8,359.7>287.930,35,35119Thenylchlor(甲氧噻草胺)19.90127.0>53.0∗,127.0>59.0,127.0>97.018,10,12

(续表1)

No.CompoundRetentiontime/minIonpairs(m/z)Collisionenergy(eV)120Tebuconazole(戊唑醇)19.92125.0>89.0∗,125.0>99.0,250.0>125.016,16,20121Bioresmethrin(生物苄呋菊酯)20.29123.1>81.1∗,143.0>128.1,171.0>128.08,10,14122Endrin-ketone(异狄氏剂酮)20.86209.2>138.4∗,316.8>208.9,316.8>281.030,28,10123Pyridaphenthion(哒嗪硫磷)20.95199.0>77.1∗,199.0>92.1,340.0>199.124,14,8124EPN(苯硫磷)21.17157.0>77.0∗,169.0>77.0,169.0>141.022,22,8125Bifenthrin(联苯菊酯)21.24165.1>163.6∗,181.0>165.9,181.0>179.024,10,12126Piperophos(哌草磷)21.32122.1>53.0∗,122.1>79.7,320.1>122.120,12,10127Methoxychlor(甲氧滴滴涕)21.39227.1>141.1∗,227.1>169.1,227.1>212.132,22,12128Fenpropathrin(甲氰菊酯)21.4797.1>55.1∗,181.0>126.8,181.0>151.96,28,22129Etoxazole(乙螨唑)21.55140.9>62.9∗,140.9>113.0,204.0>176.126,14,10130Tebufenpyrad(吡螨胺)21.60276.1>171.0∗,318.1>131.1,318.1>145.110,14,14131Anilofos(莎稗磷)21.82183.7>157.0∗,225.9>157.0,225.9>184.08,14,6132Heptachlorobiphenyl1(PCB180,七氯联苯峰1)21.84323.8>253.9∗,391.8>321.7,393.7>323.735,25,25133Azinphos-methyl(谷硫磷)22.38132.0>77.0∗,160.0>50.9,160.0>77.012,34,16134Phosalone(伏杀硫磷)22.38121.1>65.0∗,182.0>74.8,182.0>111.010,30,14135Mirex(灭蚁灵)22.70236.8>142.9∗,272.0>236.8,273.8>238.826,14,14136Iambdacyhalothrin(高效氯氟氰菊酯)23.15180.9>152.0∗,197.1>141.1,207.9>180.922,10,8137Pyraclofos(吡唑硫磷)23.79360.0>96.9∗,360.0>139.0,360.0>194.120,14,10138Etobenzanid(乙氧苯草胺)25.32149.1>121.0∗,179.1>59.1,179.1>121.08,10,10139Butafenacil(氟丙嘧草酯)25.32180.0>124.0∗,331.0>124.0,331.0>180.016,38,16140Cyfluthrin1(氟氯氰菊酯峰1)25.64163.0>127.1∗,163.0>91.1,163.0>65.16,12,26141Cyfluthrin2(氟氯氰菊酯峰2)25.83163.0>127∗,163.0>91.1,206.0>151.16,12,18142Cyfluthrin3(氟氯氰菊酯峰3)25.97163.0>127.0∗,163.0>91.1,226.0>206.16,12,12143Cyfluthrin4(氟氯氰菊酯峰4)26.05163.0>127.0∗,163.0>91.1,226.0>206.16,12,10144Cypermethrin1(氯氰菊酯峰1)26.22163.0>91.1∗,163.0>127.1,180.9>152.16,12,20145Cypermethrin2(氯氰菊酯峰2)26.42163.0>127.0∗,163.0>91.1,180.9>151.96,12,18146Cypermethrin3(氯氰菊酯峰3)26.56163.0>127.0∗,163.0>91.0,180.9>152.26,12,20147Cypermethrin4(氯氰菊酯峰4)26.63163.0>127.1∗,163.0>91.1,180.9>152.26,12,20148Etofenprox(醚菊酯)26.76163.1>77.1∗,163.1>107.1,163.1>135.132,16,10149Fenvalerate(氰戊菊酯)27.90125.0>89.0∗,125.0>89.0,167.0>89.0,167.0>125.018,18,10,32150Flumioxazin(丙炔氟草胺)27.92354.1>176.1∗,354.1>312.0,354.1>326.116,8,8151Indoxacarb(二唑虫)29.02133.9>106.0∗,203.0>106.1,203.0>134.08,22,12152Deltamethrin(溴氰菊酯)29.07181.0>152.1∗,252.8>92.9,252.8>172.022,16,8

*quantitative ion pairs(定量离子对)

图1 不同提取条件下152种农药回收率(10 μg/kg)Fig.1 152 Pesticides recoveries under different extraction conditions(10 μg/kg)

2 结果与讨论

2.1 QuEChERS法优化

2.1.1 提取与净化本研究采用蔬果中农残检测常用溶剂乙腈[13]为提取剂，考察了样品与乙腈用量不同比例(料液比)对结果的影响，发现料液比为1∶1(即5.0 g样品加5.0 mL乙腈)时的提取效果最好，可满足样品均匀性、代表性及后续步骤所需。另外，实验还考察了样品萃取时不加盐、加入氯化钠或缓冲盐(柠檬酸缓冲盐)、净化剂用量(1倍量)(2.0 mL萃取液)对结果的影响(见图1)。由图可见，柠檬酸缓冲盐会使溶液酸碱平衡，比只用NaCl萃取液盐析的效果更好，且农药的回收率更高；净化剂用量对测定结果也有较大影响，随着净化剂用量的增大，色素类杂质去除明显，干扰峰减少，但农药的回收率降低，上清液量减少，综合考虑，选择1倍量的净化试剂较适宜。

2.1.2 QuEChERS法验证实验取3组空白菜心样品各6份，每份5.0 g，152种农药的加标浓度为20、50、100 μg/kg，在优化条件下测定。结果显示，152种农药(包括异构体)在3个浓度水平下的加标回收率为68.6%～106%，相对标准偏差(RSD)为1.3%～14%(见表2)，表明经QuEChERS方法提取净化后的效果较好，满足实验要求。

表2 QuEChERS法净化条件下菜心中152种农药在3个添加水平下的回收率统计结果Table 2 The statistical results of recoveries of 152 pesticides in Chinese cabbages at 3 levels by QuEChERS

2.2 DLLME法优化

2.2.1 萃取剂与分散剂选择实验选取轻质溶剂(正己烷、环己烷、甲苯)、三氯甲烷(CHCl3)、四氯化碳、二硫化碳、正辛醇、氯苯为萃取剂进行DLLME实验，比较了萃取体系中萃取剂聚集成的液滴状态、体积稳定性、取出便利性和加标回收率，结果发现以CHCl3为萃取剂时的效果最好。另外，实验还比较了丙酮、乙腈、二氯甲烷、乙酸乙酯为分散剂时的分离效果，发现采用乙腈时效果最佳。因此，本研究中乙腈既是QuEChERS法萃取溶剂，又是DLLME分散剂。

图2 1.0 mL萃取液在不同水体积中不同萃取剂量DLLME的152种农药回收率(10 μg/kg)Fig.2 The recoveries of 152 pesticides of DLLME from 1.0 mL extract with different extraction doses in different water volumes(10 μg/kg)

2.2.2 DLLME萃取体系组成比例DLLME体系中分散剂、萃取剂和水的比例不同将影响农药组分萃取效率。分别在2～6 mL纯水和1.0 mL加标乙腈萃取液(分散剂)的不同比例体系中加入50 μL 或100 μL萃取剂CHCl3进行DLLME实验，结果如图2。实验显示4 mL水中添加1.0 mL萃取液和50 μL CHCl3于DLLME效果最佳。

2.3 GC-MS/MS条件的优化

2.3.1 质谱条件的优化以1.00 mg/L的152种农药标准液进行GC-MS/MS检测，以各组分实际出峰时间校准和调整仪器方法参数，使各组分尽可能分离良好；利用仪器全自动SRM离子对优化软件(AutoSRM)功能，优化组分的特征母离子和子离子对及其碰撞能量，提高农药组分定性和定量准确性。经优化调整质谱参数后，152种农药组分(100 μg/L)的SRM谱图见图3。

图3 152种农药标准的SRM(选择反应监测)色谱图(100 μg/L)Fig.3 SRM chromatogram of 152 pesticide standards(100 μg/L)

2.3.2 基质效应基质效应(Matrix effects，ME)[17]是指样品中非待测物在分析过程中对待测物检测有显著干扰并影响结果准确性的现象。减少ME的方法有基质净化法、同位素内标法、掩蔽剂补偿法[10,17]、空白基质配制标准溶液等[17]。用基质匹配的校准曲线斜率(A)与其纯溶剂的标准曲线斜率(B)进行比较，若A/B值在0.8～1.2之间为弱ME。实验结果发现，不采用基质匹配时不足30%农药的A/B值在上述范围内，而经基质匹配标准溶液校准后，A/B值在0.8～1.2范围内的农药达92.0%，表明基质效应被有效控制，故本方法采用空白基质匹配标准溶液绘制标准曲线。

2.4 方法学考察

2.4.1 方法校准曲线及定量下限用空白样品基质溶液配制152种农药(包括异构体)的质量浓度分别为5.0、10、20、50、100、150、200 μg/L的标准溶液，在优化条件下测定。结果显示，各组分峰面积(y)与其质量浓度(x,μg/L)在5.0～200 μg/L范围内呈良好的线性关系，相关系数均在0.995以上，计算得方法的检出限(LOD，S/N=3)和定量下限(LOQ，S/N=10)分别为0.14～2.3 μg/kg和0.45～7.7 μg/kg，结果见表3。

2.4.2 准确度与精密度取空白样品(梨)匀浆3组每组6份，每份样品5.0 g，152种农药的加标浓度为5.0、10.0、20.0 μg/kg，在优化条件下测定(表3)。结果显示，152种农药在3个加标水平下的回收率为60.6%～119%，RSD为1.5%～20%，其中样品平均加标回收率在70%～120%范围内的农药种数达133种，占总组分数87.5%。

表3 152种农药的线性方程、相关系数、检出限、定量下限及梨样品在3个添加水平的回收率和相对标准偏差(RSDs)Table 3 Linear equations,correlation coefficients(r2),limits of detections(LODs),limits of quantification(LOQs),recoveries and relative standard deviations(RSDs) of 152 pesticides in pears at three levels

(续表3)

No.CompoundLinearequationr2LOD(μg/kg)LOQ(μg/kg)Recoveries(RSD,n=6)/%5.0μg/kg10.0μg/kg20.0μg/kg33Dimethenamidy=4.36×104x+2.56×1040.99850.301.076.4(5.7)84.5(5.7)88.1(9.9)34Chlorpyrifos-methyly=4.87×104x-8.82×1040.99930.411.468.6(7.3)80.9(12)86.2(13)35Parathion-methyly=4.85×104x-1.10×1050.99880.331.168.0(7.2)79.6(12)85.0(11)36Tolclofos-methyly=1.87×104x+2.59×1030.99840.511.767.0(12)75.5(6.8)69.5(9.9)37Pirimicarby=1.92×102x-1.27×1020.99741.55.072.9(16)81.4(3.9)87.8(5.7)38Prometryny=2.15×104x+6.11×1030.99840.742.567.6(5.7)70.9(6.5)69.9(5.7)39Metalaxyly=2.58×104x+2.14×1040.99950.571.968.0(7.5)77.8(17)91.2(10)40Terbutryny=2.82×104x+4.96×1030.99910.722.463.2(10)70.3(7.7)73.2(2.9)41Fenchlorfosy=4.38×104x-6.31×1040.99940.301.071.0(10)81.1(9.2)87.3(12)42Fenitrothiony=3.45×104x-7.84×1040.99910.291.071.6(9.3)78.4(6.4)89.5(6.2)43Pirimiphos-methyly=1.79×104x+5.78×1030.99960.431.478.3(12)88.5(6.8)89.6(6.9)44Carbofuran-3-hydroxyy=9.67×102x-2.81×1020.99981.55.064.3(10)79.3(6.9)75.6(13)45Tetrachlorobiphenyl1(PCB52)y=7.16×104x+7.24×1040.99940.200.6665.8(17)72.6(1.6)78.7(12)46Dimethylvinphosy=2.49×104x-6.79×1040.99860.391.389.2(6.2)97.2(6.3)100(16)47Malathiony=5.92×104x-2.20×1050.99770.291.071.4(14)79.9(6.2)88.9(9.0)48Diethofencarby=3.66×104x-2.83×1040.99920.341.166.2(15)72.8(7.2)83.3(12)49Acetochlory=9.39×103x-4.37×1030.99900.481.668.7(5.4)75.7(12)97.7(14)50Metolachlory=1.53×105x+9.90×1020.99830.291.067.7(14)76.4(6.5)82.1(9.7)51Carbaryly=2.20×103x+4.97×1030.99911.65.571.9(15)72.3(6.9)68.5(11)52Fenthiony=2.91×104x-3.30×1040.99860.321.174.5(6.9)84.4(10)84.1(6.0)53Methiocarby=8.56×103x+3.67×1030.99951.75.881.4(15)80.0(6.2)75.3(18)54Chlorpyrifos-ethyly=3.81×104x+4.75×1020.99880.230.7576.0(10)83.4(18)83.2(9.2)55Parathiony=2.87×104x-5.77×1030.99991.13.792.0(11)96.8(2.9)104(14)56Tetraconazoley=1.07×104x-1.49×1040.99931.96.583.6(2.0)90.3(5.2)98.3(12)57Fosthiazatey=1.01×103x-2.93×1030.99871.55.174.7(16)75.9(10)69.5(7.0)58Diphenamidy=1.91×104x+1.79×1040.99950.481.664.2(8.5)71.6(7.0)70.7(17)59Aldriny=8.87×103x+1.66×1040.99930.642.163.2(10)73.6(9.3)72.6(5.6)60Cyprodinily=5.91×104x+7.36×1040.99910.341.162.0(17)78.3(13)69.9(18)61Chlorfenvinphos-E-transy=3.68×104x-4.15×1040.99940.421.480.7(5.0)87.7(4.9)89.7(10)62Dimethametryny=5.00×104x+3.50×1040.99920.411.464.9(14)76.4(10)68.2(7.6)63Heptachlorepoxidey=1.52×104x+2.34×1040.99890.672.261.6(5.0)72.0(16)68.7(19)64Oxychlordaney=2.70×104x+3.61×1040.99930.531.861.7(6.0)72.8(15)65.0(18)65Trichlorfony=6.89×103x-1.49×1030.99971.24.086.0(19)91.5(4.5)91.8(7.8)66Isofenphosy=6.95×104x-1.70×1040.99790.270.8967.9(11)78.9(12)72.2(19)67Chlorfenvinphos-Z-cisy=3.47×104x-4.07×1040.99970.461.578.0(7.6)84.0(4.0)79.2(12)68Isocarbophosy=1.15×104x+1.45×1040.99941.24.068.3(11)78.7(9.0)86.8(15)69Isofenphos-methyly=1.36×103x+2.86×1020.99982.37.768.8(12)80.1(9.3)80.4(17)70Esprocarey=1.90×105x+4.13×1020.99930.371.274.6(19)91.9(5.1)86.6(17)71Dimepiperatey=1.83×105x+5.69×1040.99970.220.7469.9(14)79.3(8.9)64.8(16)72Phoximy=1.09×104x+6.93×1030.99951.03.397.0(6.4)111(15)89.3(12)73Quinalphosy=1.73×105x-1.52×1050.99940.190.6379.8(16)84.4(4.6)92.9(11)74Phenthoatey=1.54×104x-3.86×1040.99890.501.776.0(7.9)82.7(7.8)85.7(14)75Methidathiony=1.10×105x-3.37×1050.99860.301.068.0(11)79.5(16)83.7(12)76Propaphosy=6.32×104x-3.87×1040.99980.702.372.1(12)79.7(7.5)78.1(14)77α-cis-Chlordaney=2.96×104x+5.16×1040.99890.732.460.6(3.5)71.5(14)75.5(8.1)78o,p′-DDEy=1.04×105x+1.26×1050.99910.190.6465.1(5.2)66.3(5.0)66.1(14)79Fenothiocarby=6.04×104x+5.29×1040.99940.461.577.6(10)82.2(7.8)78.0(19)80Paclobutrazoly=4.44×104x-9.09×1040.99850.642.168.0(18)75.8(4.0)78.4(15)81Pentachlorobiphenyl1(PCB101)y=4.76×104x+3.59×1030.99990.260.8661.0(10)75.5(14)76.6(16)82Tetrachlorvinphosy=1.22×104x-6.38×1040.99550.662.282.8(4.5)91.8(14)93.4(6.5)83Endosulfan1y=1.38×104x+1.39×1040.99920.451.563.8(8.4)73.1(11)71.2(7.8)84γ-trans-Chlordaney=2.08×104x+1.64×1040.99981.13.665.5(7.6)76.4(10)69.7(11)85Fenamiphosy=1.90×104x-3.71×1040.99930.431.472.1(15)81.8(4.2)80.5(19)86Butamifosy=2.61×104x-1.68×1040.99960.431.481.4(17)88.2(1.9)93.9(17)87Napropamidey=5.97×104x+4.40×1040.99910.230.7565.3(19)77.1(6.6)78.2(18)88Prothiofosy=3.31×104x+1.28×1040.99940.692.371.6(7.1)72.5(16)78.0(15)89Metominostrobin-Ey=5.28×104x+6.36×1040.99930.571.972.7(18)77.3(6.9)81.8(11)

(续表3)

No.CompoundLinearequationr2LOD(μg/kg)LOQ(μg/kg)Recoveries(RSD,n=6)/%5.0μg/kg10.0μg/kg20.0μg/kg90Profenofosy=1.68×104x-5.06×1040.99860.451.570.7(13)83.8(7.5)94.9(14)91Pretilachloy=1.02×104x+6.24×1030.99950.882.964.8(4.8)71.3(10)75.6(9.1)92Butachlory=1.91×104x+5.24×1030.99980.441.577.7(16)89.2(1.6)82.5(13)93p,p′-DDEy=1.82×105x+2.66×1050.99840.250.8565.9(6.3)65.7(14)69.3(7.4)94Dieldriny=1.20×104x+7.84×1030.99940.742.563.5(15)69.3(8.2)73.3(9.1)95p,p′-DDDy=1.75×105x+2.79×1050.99940.250.8275.0(16)61.5(13)75.8(15)96Flusilazoley=1.74×104x-1.67×1040.99961.13.664.3(15)75.2(2.8)76.0(18)97Cyproconazoley=5.17×104x-9.44×1040.99880.481.662.7(19)70.4(7.1)79.1(16)98Endriny=8.28×103x+4.06×1030.99960.491.671.1(3.7)75.2(7.3)79.7(6.4)99Fenoxanily=7.96×103x-1.71×1040.99910.361.270.5(17)81.5(4.6)84.1(18)100Chlorobenzilatey=1.47×105x-4.09×1030.99960.260.8874.4(11)82.8(10)79.9(16)101Endosulfan2y=1.87×104x+7.08×1030.99950.521.766.2(12)76.1(6.9)74.2(16)102Fensulfothiony=3.50×103x-1.52×1030.99910.752.595.3(12)92.3(13)90.1(3.9)103o,p′-DDDy=3.26×105x+2.34×1050.99980.170.5869.8(17)72.0(14)82.8(18)104o,p′-DDTy=1.23×105x-8.32×1040.99980.541.866.0(6.9)76.4(7.5)63.6(10)105Ethiony=5.21×104x-2.18×1030.99980.672.273.8(2.4)80.6(4.4)89.8(13)106Nonachlor-transy=9.52×103x+1.33×1040.99900.782.663.5(5.0)74.8(11)75.9(5.7)107EndrinAldehydey=5.06×103x+5.56×1030.99950.581.969.7(10)79.7(6.3)79.7(8.4)108Hexachlorobiphenyl1(PCB138)y=5.95×104x+5.58×1040.99970.220.7471.2(20)73.6(8.2)84.0(10)109Mepronily=3.18×105x+9.51×1040.99960.612.078.9(14)85.2(2.1)93.3(9.6)110Triazophosy=4.31×104x-1.12×1050.99860.491.687.5(14)93.5(4.2)100(14)111Benalaxyly=5.59×104x+5.22×1040.99950.301.093.7(15)91.8(7.1)93.4(17)112Carfentrazon-ethyly=4.22×103x-2.74×1030.99990.521.785.1(9.1)98.6(9.3)101(14)113Edifenphosy=2.23×104x-1.05×1050.99680.481.685.6(7.9)92.4(6.6)90.9(16)114Propiconazole1y=2.55×104x+1.28×1040.99960.682.380.6(6.9)87.0(11)89.3(8.2)115Endosulfansulfatey=1.57×104x-4.20×1040.99880.371.263.6(4.7)76.0(19)71.8(18)116p,p′-DDTy=7.00×104x-2.30×1050.99820.712.462.5(8.9)68.5(5.7)62.4(4.5)117Propiconazole2y=3.32×104x+3.21×1030.99980.672.269.3(12)76.2(17)77.9(14)118Hexachlorobiphenyl(PCB153)y=3.68×104x+3.22×1040.99970.150.5067.6(16)78.6(13)89.3(11)119Thenylchlory=4.30×104x+7.42×1030.99960.411.481.0(10)89.4(6.9)91.0(14)120Tebuconazoley=3.59×104x-6.94×1040.99860.401.370.0(9.7)79.5(7.1)85.8(11)121Bioresmethriny=5.26×104x+5.12×1040.99950.441.564.7(8.6)67.3(15)61.8(11)122Endrin-ketoney=6.14×103x-1.06×1030.99960.401.362.5(4.1)73.1(19)62.7(5.6)123Pyridaphenthiony=1.51×104x-3.67×1040.99900.541.895.8(2.6)96.6(9.1)115(16)124EPNy=4.78×104x-8.87×1040.99950.301.077.7(16)84.5(4.8)87.2(4.4)125Bifenthriny=2.22×105x+2.90×1050.99910.210.7170.8(17)85.4(8.0)85.4(14)126Piperophosy=2.96×104x-6.05×1040.99930.411.491.7(17)82.7(17)91.3(12)127Methoxychlory=4.11×104x-1.15×1050.99880.501.769.8(4.2)90.7(17)75.4(7.1)128Fenpropathriny=5.36×104x-1.64×1040.99930.571.965.2(3.7)80.4(17)79.7(13)129Etoxazoley=2.69×104x+5.09×1030.99930.521.771.4(11)81.7(9.4)84.0(17)130Tebufenpyrady=4.21×104x+3.75×1040.99950.331.184.8(9.0)92.5(2.1)101(15)131Anilofosy=1.37×104x-5.49×1040.99750.461.584.3(5.5)99.1(9.0)93.6(9.0)132Heptachlorobiphenyl1(PCB180)y=3.36×104x+2.58×1040.99990.150.5067.6(17)72.3(9.7)81.0(11)133Azinphos-methyly=3.88×103x-4.85×1030.99911.55.194.4(16)118(15)103(14)134Phosaloney=6.39×104x-2.32×1050.99760.361.276.8(4.7)91.7(13)83.7(15)135Mirexy=1.58×104x+1.58×1050.99960.220.7263.3(12)75.5(18)65.9(17)136Iambdacyhalothriny=3.82×104x-7.01×1040.99950.180.5976.1(15)76.8(11)76.7(13)137Pyraclofosy=1.67×103x-7.54×1030.99711.75.795.9(14)99.4(5.7)104(11)138Etobenzanidy=3.23×104x-3.75×1040.99971.44.6113(10)119(5.1)114(9.0)139Butafenacily=1.22×105x+7.31×1040.99990.150.5085.1(2.8)89.1(2.9)95.8(9.6)140Cyfluthrin1y=8.37×103x-9.03×1030.99970.431.471.2(5.0)82.6(9.6)66.8(10)141Cyfluthrin2y=1.08×104x-1.46×1040.99950.341.174.0(4.6)83.8(8.2)77.1(15)142Cyfluthrin3y=7.14×103x-4.12×1030.99970.301.074.0(3.9)82.9(5.2)76.4(16)143Cyfluthrin4y=8.84×103x-1.60×1040.99940.361.269.3(11)76.3(15)79.3(8.8)144Cypermethrin1y=9.47×103x-1.42×1030.99950.531.877.9(12)74.9(13)85.1(7.3)145Cypermethrin2y=9.81×103x-8.73×1030.99930.762.571.1(11)72.4(12)70.2(10)

(续表3)

No.CompoundLinearequationr2LOD(μg/kg)LOQ(μg/kg)Recoveries(RSD,n=6)/%5.0μg/kg10.0μg/kg20.0μg/kg146Cypermethrin3y=9.29×103x-8.19×1030.99970.461.574.0(14)71.3(12)79.4(7.4)147Cypermethrin4y=8.20×103x-1.80×1030.99990.491.668.9(8.6)75.3(7.9)81.4(15)148Etofenproxy=7.61×104x+1.37×1040.99990.381.376.9(4.8)84.9(7.5)86.1(12)149Fenvaleratey=1.93×104x-2.84×1040.99950.290.9870.7(1.5)81.2(4.9)80.1(13)150Flumioxaziny=4.34×103x-4.69×1030.99980.602.077.1(8.8)83.4(5.5)85.6(15)151Indoxacarby=6.62×103x-8.45×1030.99961.24.192.5(13)93.4(5.1)95.4(11)152Deltamethriny=1.36×104x-1.35×1040.99970.421.470.1(7.2)79.7(4.7)79.1(16)

the linear range of the standard curve is 5.0-200 μg/L(标准曲线线性范围是5.0～200 μg/L)

2.5 实际样品检测

应用本文建立的方法对超市和农贸市场的蔬果样品进行检测，包括26种蔬菜(油麦菜、西蓝花、苦瓜、小白菜、番茄、四季豆、胡萝卜、红薯、通菜、卷心菜、茄瓜、圣女果、南瓜、芋头、洋葱、韭黄、菠菜、花椰菜、甜椒、韭菜花、豇豆、芡实、山药、蒜薹、菜心、芥蓝)和14种水果(苹果、梨、桃、蓝莓、葡萄、猕猴桃、香蕉、樱桃、柑橘、李子、橙子、哈密瓜、柿子、火龙果)，各30份样品。结果显示，有24份蔬菜样品共检出31种农药残留，占总152种农药的20.4%；检出含量为1.5～2 649.8 μg/kg，其中含量低于50 μg/kg的占70.7%；有3份蔬菜样品中的农残超标：菠菜中氟硅唑含量为1.23 mg/kg；苦瓜中氯氰菊酯(异构体之和)为0.93 mg/kg；油麦菜中戊唑醇为2.65 mg/kg，此外还检出氟硅唑、丙环唑等农药(见图4)。有25种水果样品检出农残，涉及20种农药组分，占农药总数13.2%；没有水果样品农药超标，检出范围是1.7～325.5 μg/kg，含量低于50 μg/kg的占91.2%。

图4 油麦菜SRM色谱图Fig.4 SRM chromatogram of leaf lettuce

3 结 论

采用优化QuEChERS法和DLLME法联合处理样品，使样品农残的萃取效率、液滴稳定性和易操作性好，目标物浓缩倍数高，检测更灵敏准确；这两种前处理方法与优化的GC-MS/MS方法联用构建的高通量农药多残留检测方法，更经济、高效且操作简单,能较好地满足新鲜蔬果中农药残留的快速筛查和应急检测的需要。