农药的超临界流体色谱-质谱分析（SFC-MS）

本应用说明中结论：The SFC-UV detected 5 out of 6 pesticides at 1ppm. All 6 pesticides produced a S/N of greater than 2 at  2ppb on a single quad MS in just over 5 minutes using SFC-MS. The SFC-MS identified26 out of 32  pesticides in 6 minutes.UASGOApplication Note 2/6Analysis of Pesticides using Supercritical Fluid Chromatography with Mass Spectrometry Analysis of Pesticides using Supercritical Fluid Chromatography with Mass Spectrometry [SFC-MS ] Pesticide analysis is required for consumer safety for food consumption. In 1996 the US FDA implemented regular m onitoring of domestic a nd imported foods. There are 1000 regist e red pesticides by the US an d 1100 by the European Union. The upper allowable limit is 10ppb or less.Japan has 16 pesticides that have zero tolerance.Wi t h the above requirements ， extremely sensitive pesticide analysis is required. HPLC with fluorescence detection is a common system used to analyz e certain pesticides.F l u orescence is a very sensitive detector ， b ut of course it does n o t aid in the ident i fication that MS can offer. The speed of SFC combined with the sensitivity and identif i cation of Mass Spectrometry was explored for pesticides. Jasco PU-2080 Pl u s pump CO， Delivery Pump： PU-2080-CO2 Column： Luna Modifier Pump： DG-2080 C18(4.6mmlDx150mmL，5 um)Mixer： MX-2080-32 CO， Flowrate： 5.0mL/min Autosampler ： AS-2057 Modifier ： 20mM Ammonium Column Oven： CO-2060acetatein Methanol PDA Detector ： MD-2018Modi f ier Gradient： 0min95% CO，： 5% MeOH Mass Spec： Agilent G6130 4 min 65% CO， ： 35%MeOH Back Pressure Regulator ： BP-20804.1min 50% CO， ： 50%MeOH 7 min 50% CO， ： 50%MeOH 7.1 min 95% CO，：5% MeOH Column T emperature：40°C Back Pressure： 100 Wavelength： 220nm APCI Source S electe d I o n Moni tor (SI M) Drying Gas Flow：12 L/min Fragmentor：70.0Nebulizer Press ：35psi G a i n ：1.0Drying Gas Temp：250°C Threshold：150Vaporizer Temp：250°C Step size：0.1Cap i llary Voltage：3000V Corona Current：4.0uA F i g u re 1. Stru c t u r e s of the 6 pest i cides used for i ni t ial UV detector test in g . Figure 2. Over l ay of SFC-UV chromatograms of 6 P esticides. 1. Malathion ， 2. Chloryriphos， 3. Carbofuran， Coumaphos， 5. Car b aryl ， 6. Duron. F i gur e 3. St a cked SFC-UV chromatograms of Carbaryl . The struct u res of t he 6 pest i c i des is shown in f igu re 1 and those 6 were each run and an overlay o f t heir chromatog ra ms is shown i n fi gu r e 2. Carba r yl is shown at various concentrat i ons i n f i gu re 3. F i ve out of t he six pesticides were detected at 1p pm with UV alone. T he MS was next used to increase the sensit i vity. Figure 4. SFC-MS SIM chromatogram of 6 pes t ic i de m i x (0.5ppm eac h). Col u mn SFC pak Si l -5 (4.6x250mm ， 5u m)T h e SFC-MS chromatogram of the 6 pesticides at 0.5ppm a n d the corresponding spectra are shown in fig u re 4 and 5， r espect iv ely. The sensit i vity was test at various concent r ations 0.5pmm to 2ppb (F i gure 6). A mixt u re of 32 pesticides (eac h 0.5ppm) was i nj ected and 26 of t h e m were detected and identif i ed us in g t h e same co n ditions on the silica column.T he i de n t i tie s and th e retention times o f each are s h own in table 1. F i gure 5. MS Pea k Spectra Confirming Pesticide Ident i ty. Figure 6. Sta c ked SFC-MS SIM chroma t ograms o f 6 pestici de m i x. Conditi o ns wer e the same as sh o wn i n previo u s slides.S/N of 2 or grea t e r for all 6 pest i cides a t 2pp b . Figure 7. Ov e rlay o f XIC of 26 pest i cides u sin g SFC-MS.26 of 32 pesticides were detected using SFC-MS. Pesticide Molecular Weight Retention Time Azinphosmethyl 317.3 3.6 Atrazine 215.7 3.03 Oxadiazon 345.2 1.9 Omethoate 213.2 5.8 Kresoxim-methyl 313.4 2.5 Chlorfenapyr 407.6 2.35 Diflufencian 394.3 2.7 Dimethoate 229.3 4.9 Spiroxamine 297.5 3.3 Thiobencarb 257.8 2.2 Tefluthrin 418.7 1.9 Terbutryn 241.4 5.04 Terbufos 288.4 1.6 Pesticide Molecular Weight Retention Time Trifluralin 335.3 3.6 Norfluazon 303.7 3.03 Pyrethrins 328.4，372.5 1.9，1.1 Fenamiphos 303.4 5.9 Fenarimol 331.2 4.6 Fenpropimorph 303.5 5.8 Fluvalinate 502.9 2.4 Procymidone 284.1 4.2 Trans-permethrin 391.3 2.6 Pendimethalin 281.3 1.67 Malathion 330.4 2.1 Methidathion 302.3 2.7 Conclu s ion The SFC-UV detected 5 out of 6 pest i cid e s at 1ppm. Al l 6 pestici d es produced a S/N of greater than 2 at 2ppb on a s i ngle quad MS in just over 5 minutes using SFC-MS . The SFC-MS i dentif i ed26 out of 32pesticides in 6 minutes .