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Featured Application: Multiresidue Pesticide Mix Extracted from Brown Rice Flour Using QuEChERS Extraction and Cleanup

7.5-Min Screening Analysis of Multiresidue Pesticides in Brown Rice Flour


  • 7.5-min analysis with complete analytical cycle time of less than 10 min.
  • Over 90% of the 200+ residues analyzed exhibit recoveries between 70-120%.
  • Compatible with both traditional HPLC and modern UHPLC instruments.

Analysis of multiresidue pesticides is no easy task, and it’s made even more difficult by complex sample matrices and the sophistication of the LC-MS/MS instrumentation commonly used for analysis. An LC-MS/MS can provide remarkable sensitivity, even allowing a degree of chromatographic coelutions to exist and still quantitatively monitor analytes of interest. However, too many coelutions can overwhelm the mass spectrometer, so a good chromatographic method is still essential. The optimized chromatographic method described here allows the analysis of hundreds of compounds in as little as 7.5 minutes with a total cycle time under 10 minutes, ensuring fast, accurate sample screening and increased lab productivity.

As detailed below, a sample of brown rice flour was fortified with all of the components included in the Restek LC multiresidue pesticide kit, extracted with Q-sep QuEChERS extraction salts, cleaned up using dSPE, and analyzed using a 2.7 µm Raptor ARC-18 column. The inherent efficiency of a 2.7 µm superficially porous particle column produces narrow peaks, which permits more compounds to be fit into a given unit of time. The selectivity of the Raptor ARC-18 stationary phase ensures that compounds elute throughout the entire length of the analysis, which avoids crowding compounds in time and potentially taxing the mass spectrometer’s ability to monitor all the relevant ions effectively. Note that it is important to keep internal system volume down to a minimum, so selecting narrow-bore LC tubing and avoiding excess lengths of tubing will help produce the narrowest peaks and achieve the quickest, most efficient chromatography. This analysis of multiresidue pesticides in brown rice flour uses straightforward mobile phases that are mass spec friendly and a flow rate that keeps the back pressure within the operating range of conventional HPLC instruments. These advantages make it possible to analyze over 200 pesticides, surrogates, and internal standards—even in such a challenging matrix—in a matter of minutes.


PeakstR (min)Precursor IonProduct Ion 1Product Ion 2
1.Cyromazine0.747167.168.143.1
2.Methamidophos1.318142.094.0125.1
3.Formetanate1.681222.1165.046.1
4.Carbofuran1.682222.2165.0123.1
5.Methabenzthiazuron1.686222.0165.0150.0
6.Acephate1.690184.0143.049.0
7.Pymetrozine1.708218.1105.078.0
8.Aminocarb1.716209.1137.1152.1
9.Propamocarb1.735189.1102.0144.1
10.Omethoate1.905214.0125.0183.0
11.Dinotefuran1.972203.1129.187.1
12.Aldicarb sulfoxide2.010207.189.0132.1
13.Butoxycarboxim2.022223.0106.0166.0
14.Nitenpyram2.049271.0225.056.0
15.Aldicarb sulfone2.062240.2148.086.0
16.Carbendazim2.090192.0160.0131.9
17.Oxamyl2.154237.172.090.0
18.Flonicamid2.234230.1203.0148.0
19.Methomyl2.259163.188.0106.1
20.Thiabendazole2.284201.892.2104.0
21.Thiamethoxam2.289292.1211.1181.1
22.Fuberidazole2.368185.0157.1103.0
23.Monocrotophos2.375224.1127.0193.1
24.Mexacarbate2.393223.2166.1151.1
25.Dioxacarb2.397224.1167.077.1
26.Dicrotophos2.526238.1112.172.0
27.Imidacloprid2.536256.1175.0209.0
28.Clothianidin2.545250.0169.0113.0
29.Dimethoate-d6 (IS)2.652236.2205.2131.2
30.Fenuron2.662165.072.146.1
31.Trichlorfon2.667257.0108.9220.8
32.Dimethoate2.668230.0199.0125.0
33.3-Hydroxycarbofuran2.679238.1181.0163.0
34.Vamidothion2.695288.0146.0118.0
35.Mevinphos2.715225.1127.0127.0
36.Acetamiprid2.724223.0126.056.1
37.Propoxur2.777210.0111.0168.0
38.Ethirimol2.780210.2140.298.2
39.Cymoxanil2.805199.1128.2111.2
40.Thiacloprid2.865253.0126.099.0
41.Pirimicarb2.896239.272.0182.1
42.Aldicarb3.022208.2116.289.2
43.Tricyclazole3.066190.0163.0136.0
44.Oxadixyl3.076279.1219.1132.1
45.Carbetamide3.085237.1192.0118.1
46.Simetryn3.122214.168.096.0
47.Thiophanate-methyl3.146343.0151.0311.1
48.Thidiazuron3.150221.1102.1127.9
49.Bendiocarb3.212224.1167.1109.0
50.Imazalil3.225297.1159.041.1
51.Prometon3.227226.1142.1184.0
52.Metribuzin3.230215.1187.1131.0
53.Secbumeton3.232226.2170.2100.2
54.Terbumeton3.235226.1114.1170.1
55.Sulfentrazone*3.263387.0309.0201.0
56.Pyracarbolid3.279218.1125.197.0
57.Tebuthiuron3.310229.1172.1116.0
58.Carbaryl3.316202.1145.0127.0
59.Carboxin3.326236.1143.087.1
60.Monolinuron3.373215.1126.0148.0
61.Fluometuron3.381233.172.146.1
62.Diuron3.382233.172.146.0
63.Ethiofencarb3.406226.0107.0164.0
64.Ametryn3.447228.168.1186.1
65.Chlorotoluron3.450213.072.146.1
66.Metobromuron3.483259.0170.0148.1
67.Propham3.500180.1120.277.1
68.Flutriafol3.508302.070.1123.0
69.Methoprotryne3.532272.1170.0198.1
70.Forchlorfenuron3.536248.1129.093.0
71.Isoprocarb3.537194.195.1137.1
72.Fenpropimorph3.561304.2147.1117.0
73.Atrazine-d5 (SS)3.575221.2179.2101.3
74.Isocarbophos3.606291.1231.1121.1
75.Isoproturon3.612207.172.146.1
76.Desmedipham3.620318.0154.1301.0
77.Phenmedipham3.623318.1108.193.1
78.Spiroxamine3.626298.2144.258.2
79.Pyrimethanil3.659200.0107.082.0
80.Metalaxyl3.691280.1220.1192.1
81.Chlorantraniliprole3.730484.0452.8285.8
82.Cycluron3.785199.189.146.0
83.Prometryn3.830242.1158.0200.2
84.Linuron-d6 (SS)3.843255.1160.1185.2
85.Linuron3.854249.0160.0182.0
86.Thiofanox3.876242.157.2184.0
87.Fenobucarb3.894208.095.1152.1
88.Azoxystrobin3.915404.2329.0344.0
89.Diethofencarb3.924268.1226.1124.0
90.Ethofumesate3.925304.1121.1241.0
91.Ethiprole3.932397.0350.9255.0
92.Fludioxonil*3.935247.1180.1126.1
93.Methiocarb3.958226.1169.1121.1
94.Siduron3.967233.394.0137.1
95.Halofenozide3.974331.1104.9275.0
96.Fenamidone3.993312.092.1236.1
97.Furalaxyl3.995302.1242.195.0
98.Acibenzolar-S-methyl4.023210.9136.191.1
99.Nuarimol4.030315.1252.0207.0
100.Dimethomorph4.044388.2300.9165.1
101.Boscalid4.050343.0306.8140.0
102.Mandipropamid4.067412.1328.1125.0
103.Flutolanil4.079324.1262.0242.0
104.Promecarb4.104208.1109.0151.0
105.Paclobutrazol4.119294.070.1125.0
106.Triadimenol4.119296.170.143.1
107.Mepronil4.161270.191.1119.0
108.Cyproconazole4.175292.270.1125.0
109.Myclobutanil4.195289.270.1125.1
110.Chloroxuron4.225291.172.146.1
111.Bupirimate4.226317.2166.0237.1
112.Methoxyfenozide4.230369.2149.0313.1
113.Triadimefon4.287294.069.0197.0
114.Bifenazate4.290301.1198.0170.1
115.Cyprodinil4.313226.193.077.0
116.Mefenacet4.325299.1148.1120.1
117.Mepanipyrim4.334224.177.1106.1
118.Fluquinconazole4.346376.0348.9307.0
119.Fenhexamid4.383302.197.155.1
120.Fluoxastrobin4.385459.2427.0188.1
121.Tetraconazole4.387372.0159.070.0
122.Bromuconazole isomer 14.392376.0159.0159.0
123.Butafenacil4.411492.1330.9179.9
124.Iprovalicarb4.412321.2119.091.1
125.Flufenacet4.427364.1152.0194.1
126.Triticonazole4.429318.070.0125.0
127.Cyazofamid4.441325.1108.044.0
128.Diflubenzuron4.464311.0158.0141.0
129.Spirotetramat4.478374.1330.1302.0
130.Fenarimol4.510331.0267.9189.1
131.Fenbuconazole4.516337.0125.070.1
132.Epoxiconazole4.529330.0121.1101.0
133.Etaconazole4.552328.1159.055.0
134.Fipronil*4.571436.9332.0252.0
135.Neburon4.635275.057.188.1
136.Flusilazole4.646316.1247.1165.1
137.Fenoxycarb4.653302.288.1116.1
138.Picoxystrobin4.674368.0145.0205.0
139.Rotenone4.683395.1213.1192.1
140.Tebufenozide4.719353.2133.1105.0
141.Dimoxystrobin4.738327.1205.1116.1
142.Bromuconazole isomer 24.740378.0159.0159.0
143.Flubendiamide4.745700.0408.0274.0
144.Diclobutrazol4.764328.070.1159.0
145.Carfentrazone ethyl4.773429.1412.1346.1
146.Kresoxim-methyl4.795314.0267.1116.0
147.Tebuconazole4.827308.070.1124.9
148.Spinosad A4.840732.5142.198.1
149.Penconazole4.853284.170.1159.0
150.Prothioconazole4.857344.0189.0154.0
151.Zoxamide4.893336.1187.0159.0
152.Famoxadone4.933392.2331.1238.0
153.Diazinon-diethyl-d10 (IS)4.961315.2170.2154.3
154.Hydramethylnon4.979495.2323.245.2
155.Triflumuron4.986359.1156.0111.0
156.Prochloraz4.986376.0308.070.1
157.Hexaconazole4.993314.170.0158.8
158.Benalaxyl5.021326.2148.0208.1
159.Metconazole5.033320.170.1125.0
160.Propiconazole5.054342.0159.069.0
161.Pyraclostrobin5.076388.0194.0163.1
162.Clofentezine5.080303.0138.0102.0
163.Bitertanol5.120338.2269.270.1
164.Spinosad D5.142746.5142.098.0
165.Benzoximate5.171364.0199.1105.0
166.Diniconazole5.184326.170.0158.9
167.Thiobencarb5.197258.0125.089.1
168.Pencycuron5.229329.1125.089.0
169.Spinetoram5.234748.5142.198.2
170.Hexaflumuron*5.351459.0439.0175.0
171.Triflumizole5.366346.1278.073.1
172.Indoxacarb5.375528.1149.9203.0
173.Difenoconazole5.380406.1251.1152.0
174.Ipconazole5.426334.270.0124.9
175.Trifloxystrobin5.426409.0186.0206.0
176.Novaluron*5.455491.0471.0304.9
177.Emamectin-benzoate B1b5.463872.2158.282.1
178.Clethodim5.565360.1164.1268.1
179.Teflubenzuron5.614380.9140.9158.0
180.Alanycarb5.636400.191.0238.0
181.Buprofezin5.642306.2106.186.0
182.Emamectin-benzoate B1a5.644886.5158.082.1
183.Benfuracarb5.695411.2194.9251.9
184.Fluazinam*5.726463.0415.9397.9
185.Metaflumizone*5.728505.1302.1328.0
186.Furathiocarb5.735383.1195.0252.1
187.Temephos5.757467.1125.0418.9
188.Lufenuron5.767511.2141.0158.0
189.Tebufenpyrad5.778334.0117.0145.0
190.Pyriproxyfen5.843322.096.0227.1
191.Piperonyl butoxide5.864356.2177.0119.1
192.Hexythiazox5.924353.2228.0168.1
193.Quinoxyfen5.935308.1197.0162.0
194.Flufenoxuron5.984489.1158.0141.0
195.Propargite6.088368.1231.1175.0
196.Etoxazole6.099360.2141.057.1
197.Spiromesifen6.129371.3273.2255.2
198.Chlorfluazuron6.165539.8382.9158.0
199.Spirodiclofen6.269428.371.1313.1
200.Fenpyroximate6.283422.1366.1138.1
201.Pyridaben6.442365.2147.0309.1
202.Eprinomectin6.466914.6186.1154.1
203.Abamectin B1a6.544890.6305.4567.2
204.Fenazaquin6.559307.1161.0131.1
205.Doramectin6.733916.6331.2593.4
206.Ivermectin6.893892.6551.4569.4
*Detected in ESI- mode
LC Multiresidue Pesticide Mix Extracted from Brown Rice Flour with QuEChERS Slim Pouch on Raptor ARC-18 by LC-MS/MS
LC_FS0521
ColumnRaptor ARC-18 (cat.# 9314A12)
Dimensions:100 mm x 2.1 mm ID
Particle Size:2.7 µm
Pore Size:90 Å
Guard Column:Raptor ARC-18 EXP guard column cartridge 5 mm, 2.1 mm ID, 2.7 µm (cat.# 9314A0252)
Temp.:50 °C
SampleLC multiresidue pesticide kit (cat.# 31971)
Diluent:Water:acetonitrile 9:1
Conc.:1 ng/mL see notes for details
Inj. Vol.:5 µL
Mobile Phase
A:0.2% Formic acid, 2 mM ammonium formate in water
B:0.2% Formic acid, 2 mM ammonium formate in methanol
Time (min)Flow (mL/min)%A%B
0.000.4955
2.000.44060
4.000.42575
6.000.40100
7.500.40100
7.510.4955
9.500.4955
DetectorMS/MS
Ion Mode:ESI+/ESI-
Mode:Scheduled MRM
InstrumentUHPLC
NotesAlthough the ten LC multiresidue pesticides kit mixes are formulated to ensure maximum long-term stability and reliability as packaged, stability may become an issue when a large number of compounds with different chemical functionalities are combined together into a single mix. This should be taken into consideration for quantitative analysis.

Sample Preparation:
Brown rice flour (10 g), purchased from a local market, was mixed with 10 mL water. After mixing for 10 min, the brown rice flour was fortified at 10 ng/g with all residues from the LC multiresidue pesticide kit (cat.# 31971), which had been previously combined into a single mixture that day. The fortified brown rice flour suspension was then mixed for 30 min to ensure uniform dispersion of the added pesticide residues in the brown rice flour suspension. Extraction was performed using 10 mL of acetonitrile and original unbuffered QuEChERS salts (cat.# 25848). After centrifugation, 1 mL supernatant was added to a 2 mL dSPE vial containing magnesium sulfate, PSA, and C18 (cat.# 26125) for cleanup. After centrifugation, 100 μL of the 10 ng/mL extract was diluted with 900 μL water and injected onto the UHPLC.

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