Food Chemistry 134 (2012) 2398–2405

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Food Chemistry

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Analytical Methods

Finding of pesticides in fashionable fruit juices by LC–MS/MS and GC–MS/MS

Kevin Tran a, David Eide a, Susan M. Nickols a, Michele R. Cromer a, Armando Sabaa-Srur b,Robert E. Smith a,⇑a Total Diet and Pesticide Research Center, US Food and Drug Administration, 11510 W 80th St., Lenexa, KS 66214, United Statesb Department of Basic and Experimental Nutrition, Nutrition Institute, Federal University of Rio de Janeiro, United States

a r t i c l e i n f o

Article history:Received 6 May 2011Received in revised form 26 September 2011Accepted 7 April 2012Available online 21 April 2012

Keywords:AçaíGojiMangosteenNoniPomegranateSea buckthornLC–MS

0308-8146/$ - see front matter Published by Elsevierhttp://dx.doi.org/10.1016/j.foodchem.2012.04.034

⇑ Corresponding author. Tel.: +1 913 752 2127; faxE-mail address: robert.smith@fda.hhs.gov (R.E. Sm

a b s t r a c t

Products labelled as containing extracts from two mushrooms (cordyceps plus reishi) and the juices fromaçaí, goji, mangosteen, noni, pomegranate, and sea buckthorn have been analysed for 174 different pes-ticides, using the validated QuEChERS method for sample preparation and electrospray LC–MS/MS in thepositive ion mode for analysis. Pesticides were found in 10 of the 21 samples analysed. Most pesticidesfound were below the tolerance levels (1–6 lg/g, depending on the pesticide), but some were not. Thisincluded boscalid, dimethomorph, iprovalicarb, pyridaben, pyrimethanil, and imazalil, for which thereis no tolerance reported or zero tolerance in any fruit. However, genuine açaí that was harvested inthe state of Pará and lyophilised in Rio de Janeiro had no detectable pesticides, when analysed by bothLC–MS/MS and GC–MS/MS, which can detect 213 more pesticides and industrial chemicals. Likewiseno pesticides were found in one sample each of cordyceps plus reishi, sea buckthorn and noni.

Published by Elsevier Ltd.

1. Introduction

The juices of açaí (Euterpe oleracea Martius), goji (Lycium barba-rum), mangosteen (Garcinia mangostana), noni (Morinda citrifoliaL.), pomegranate (Punica granatum) and sea buckthorn (Hippophaerhamnoides) have become fashionable and are widely consumed, ashave combined extracts of the mushrooms cordyceps (Cordycepssinensis) plus reishi (Ganoderma Lucidum) (Brondízio, Safar, &Siqueira, 2002; Dog, 2009; Johanningsmeier & Harris, 2011). Manyproducts that are sold in the USA and over the Internet are labelledas containing one or more of these fruits, either as a juice or alyophilised (freeze-dried) solid. Part of the appeal of these productsis that they are organic and should not have any human-made pes-ticides or industrial chemicals.

Açaí is the common name for the large palm tree, E. oleraceaMartius. Its fruit is harvested when it turns purple. The edible por-tion corresponds to only 7% of the fruit weight. In order to make iteasier to obtain the pulp, water is added while de-pulping the fruit.According to the amount of water added during this process, it pro-duces Açaí Grosso (which means thick açaí) containing >14% of to-tal solids, Açaí Médio (medium açaí) containing between >10% and614% of total solids and the Açaí Popular (popular açaí or thin açaí)

Ltd.

: +1 913 752 2122.ith).

containing 610% of total solids. The pH is between 5.3 and 5.6. Thepulp is dried to contain about 40% fat. Even though many of thechemical components of açaí are known, they are also known tobe in other fruits. So, there is no way to test samples labelledaçaí to see if they are authentic, as there is for pomegranate juice(Johanningsmeier & Harris, 2011; Zhang, Wang, Lee, Henning, &Heber, 2009). In fact, a market survey of commercial sources ofproducts labelled as containing pomegranate found that only sixout of 23 met the proposed standards for authenticity (Zhanget al., 2009). Like açaí, pomegranate juice looks like grape juice,which often contains pesticides. Since grape juice costs much lessthan açaí or pomegranate juice, it would be a cost-effective choicefor adulteration. So, one way to look for adulteration and fraud is tolook for pesticides. The previously validated LC–MS/MS method(Sack et al., 2011) can detect 174 pesticides, but these do not in-clude pyrethoids (such as cypermethrin, cyfluthrin, deltamethrin,permethrin, lambdacyhalothrin and fenpropathrin) that have beenused in past years to prevent infestations (Rozendaal, 1997) of tri-atomine bugs that can carry Trypanasome cruzei, the aetiologicalagent for Chagas disease, which may be caused by consuming con-taminated açaí (Nóbrega et al., 2009). Instead, GC–MS/MS isneeded. As part of a more extensive project to analyse products la-belled as containing açaí, it was decided to submit the Brazilianaçaí to the more extensive analysis that included GC–MS/MS. Thisadded 213 more pesticides and industrial chemicals to the list ofanalytes in Brazilian açaí.

Table 1MS transition parameters. Q1 and Q2 and the m/z of the two ions used for quantitation. DP is the declustering potential, CE is the collision energy and EXP is exit potential.

Compound Transition 1 Transition 2

Q1 Q2 DP CE EXP Q1 Q2 DP CE EXP

3-Hydroxycarbofuran 238.1 163 66 21 15 238.1 181 66 16 11Acephate 184.1 143 61 13 5 184.1 49 61 33 6Acetamiprid 223.0 126 60 29 10 223 99 60 51 14Acibenzolar-S-methyl 211.0 136 46 39 8 211 140 46 31 8Alanycarb 400.1 238.2 35 14 5 400.1 91.1 35 40 5Aldicarb + NH4 208.1 116 35 11 10 208.1 89 35 23 16AldicarbSulfoxide 207.1 132.1 30 10 8 207.1 89.1 30 19 6Aldoxycarb 223.1 86.1 52 21 5 223.1 148 52 13 9Aminocarb 209.1 152 71 21 8 209.1 137.1 71 35 10Amitraz 294.2 163.2 46 21 4 294.2 107.1 46 57 4AvermectinB1a + NH4 890.9 567.7 75 23 18 890.9 305.4 72 35 22AvermectinB1b + Na 876.5 291 41 35 4 876.5 145 41 43 4Azoxystrobin 404.1 372.1 51 19 5 404.1 344.1 51 27 5BDMC 260 122 52 34 5 260 107 52 54 5Benalaxyl 326.2 148.1 71 31 8 326.2 294.1 71 17 10Bendiocarb 224.1 109 61 27 20 224.1 167.1 61 15 12Benfuracarb 411.2 195.1 50 30 5 411.2 252.1 50 19 5Bentazon 241 199 76 19 8 241 107 76 39 8Benzoximate 364 199 51 13 13 364 105 51 35 4Bifenazate 301.1 170.1 59 30 9 301.1 198.1 59 21 10Bitertanol 338.2 70 51 31 12 338.2 269.2 48 13 14Boscalid 343 307 90 27 7 343 140 90 27 6BromuconazoleA 378 159 61 39 12 378 70 61 43 12BromuconazoleB 378.1 159.1 61 39 12 378.1 70.1 61 43 12Bupirimate 317 166.1 86 33 12 317 108 86 37 10Buprofezin 306.2 201.1 46 17 5 306.2 116.2 46 21 5Butafenacil + NH4 492.1 331 58 33 16 492.1 349 61 21 12Butocarboxim + Na 213.1 75 50 21 6 213.1 116 50 13 6Butoxycarboxim 223.1 106 45 15 8 223.1 166 45 11 5Carbaryl 202.1 145 57 15 9 202.1 127 54 41 8Carbendazim 192.2 160.2 80 24 10 192.2 132.1 80 41 7Carbetamide 237.1 192 55 13 10 237.1 118.1 56 19 10Carbofuran 222.1 123 66 31 19 222.1 165.1 66 19 11Chlorantraniliprole 484 452.9 66 23 14 484 285.9 66 19 16Chlorfluazuron 540 158 91 27 4 540 383 91 28 4Chlorotoluron 213.1 72.2 61 31 5 213.1 46.2 61 27 5Chloroxuron 291.1 72.4 65 34 5 291.1 218.1 65 30 5Clethodim 360.1 164 61 28 9 360.1 268.1 61 17 8Clofentezine 303 138 65 22 8 303 102 65 51 14Clothianidin 250 169 51 17 4 250 132 51 21 10Cyazofamid 325 108 60 20 9 325 261.1 60 15 13Cycluron 199.1 89.1 50 21 5 199.1 72.2 50 21 4Cyflufenamid 413.1 295.1 56 23 8 413.1 223.1 56 33 14Cymoxanil 199 128 60 13 5 199 111 60 25 5CyproconazoleA 292 70 63 37 10 292 125 63 43 8CyproconazoleB 292.1 70.1 63 37 10 292.1 125.1 63 43 8Cyprodinil 226 93 95 49 13 226 77 95 64 12Cyromazine 167.1 85.1 62 27 15 167.1 125.1 62 27 8Desmedipham + NH4 318.1 182 42 19 10 318.1 136 39 34 9Diclobutrazol 328.1 70 81 49 12 328.1 158.9 81 49 10Dicrotophos 238.1 112.1 66 19 8 238.1 193 66 15 13Diethofencarb 268.1 226.1 60 15 12 268.1 124 61 45 8Difenoconazole 406.1 251.1 80 37 13 408.2 253.1 76 33 5Diflubenzuron 311 158.2 71 23 10 311 141.1 71 45 10Dimethoate 230 199 49 16 12 230 125 50 27 8DimethomorphA 388.1 301 66 25 5 388.1 165.1 66 45 5DimethomorphB 388.2 301.1 66 25 5 388.2 165.2 66 45 5Dimoxystrobin 327.1 205 40 15 5 327.1 116 40 35 5Dinotefuran 203.1 129.2 51 19 8 203.1 157.2 51 13 14Dioxacarb 224.1 167 51 13 10 224.1 123 51 23 21Diuron 233.1 72 56 33 5 235.1 72.1 56 38 10Doramectin + NH4 916.9 593.6 68 20 16 916.9 331.5 65 33 22Emamectin 886.5 158.1 111 51 10 886.5 82.1 111 127 13Eprinomectin 914.5 186.2 77 27 12 914.5 154.2 77 58 10Ethaboxam 321 183.1 86 33 12 321 200.1 86 39 12Ethiofencarb 226.1 106.9 41 21 5 226.1 164.1 41 11 5Ethiprole 397.3 350.9 81 29 24 397.3 255.2 81 49 16Ethirimol 210.2 140.1 81 31 8 210.2 98.1 81 39 18Etoxazole 360.1 141 76 45 5 360.1 57.2 76 45 5Famoxadone + NH4 392 331 32 15 6 392 238 37 23 6Fenamidone 312.1 92 66 39 16 312.1 236.1 66 21 14Fenazaquin 307.1 161.1 68 27 10 307.1 147 68 28 9Fenbuconazole 337 124.9 81 41 8 337 70 81 39 12

(continued on next page)

K. Tran et al. / Food Chemistry 134 (2012) 2398–2405 2399

Table 1 (continued)

Compound Transition 1 Transition 2

Q1 Q2 DP CE EXP Q1 Q2 DP CE EXP

Fenhexamid 302 97 75 34 14 302 55 75 67 9Fenobucarb 208.1 95.1 61 21 18 208.1 152.1 61 13 10Fenoxycarb 302.1 88 65 30 6 302.1 116.1 65 17 7Fenpyroximate 422 366.1 56 23 5 422 135.1 56 43 5Fenuron 165.1 72.1 56 25 5 165.1 46 56 29 5Flonicamid 230.1 203.1 55 35 4 230.1 174 55 35 4Flubendiamide 683 408 56 17 12 683 274 56 43 16Fludioxinil + NH4 266 229 41 23 14 266 227.1 41 13 14Flufenoxuron 489 158 86 29 10 489 141.1 86 63 8Fluometuron 233.1 72.1 71 37 12 233.1 46 71 35 4Fluoxastrobin 459.2 427.2 55 28 5 459.2 188 55 35 5Flusilazole 316.1 247.1 78 27 14 316.1 165.1 78 38 9Flutolanil 324.1 262.1 74 26 14 324.1 242.1 74 34 12Flutolanil + NH4 341.1 242.1 61 35 4 341.1 262.1 61 35 4Flutriafol 302.1 70.1 66 37 12 302.1 123 66 41 8Forchlorfenuron 248 129.1 52 25 5 248 93.1 52 48 5Formetanate 222.1 165 71 22 9 222.1 93 76 53 14Fuberidazole 185 157 81 33 13 185 65 81 67 11Furathiocarb 383.1 195.1 74 26 10 383.1 252.1 74 19 14Halofenozide 331.1 275 41 11 16 331.1 105.1 41 25 8Hexaflumuron 461.1 158.2 56 25 5 461.1 141.1 56 65 5Hexythiazox 353.1 228 63 23 12 353.1 168 63 36 9Hydramethylnon 495.2 323.2 146 45 18 495.2 151.1 146 95 8Imazalil 297 159 65 34 12 297 201 65 29 10Imidacloprid 256 209.1 61 23 10 256 175.1 61 28 10Indoxacarb 528 203 89 54 10 528 218 86 33 14Ipconazole 334.2 70 74 52 10 334.2 125 74 50 17Iprovalicarb 321.2 119 66 29 8 321.2 203.1 66 13 13Isoprocarb 194.1 95 60 23 13 194.1 137 60 13 10Isoproturon 207.2 72.1 66 29 5 207.2 46.1 66 31 5Isoxaflutole 360.1 251.1 62 24 9 360.1 220.1 62 50 9Isoxaflutole + NH4 377 251.1 56 29 14 377 69 56 35 12Ivermectin + NH4 892.8 569.7 70 21 20 892.8 713.8 71 15 24Kresoxim-methyl 314 116 51 21 4 314 206 51 13 4Linuron 249.1 160 60 23 5 249.1 182.1 60 21 5Lufenuron 511.1 158.1 61 27 5 511.1 141.2 61 67 5Malathion 331 127 71 19 8 331 285 71 11 16Mandipropamide 412.1 328.1 81 21 10 412.1 356.1 81 17 10Mepanipyrim 224 106 86 37 8 224 77 86 59 14Metaflumizone 507.1 178.1 101 39 12 507.1 287.1 101 37 16Metalaxyl 280.1 220.2 60 20 12 280.1 192.2 60 26 10Metconazole 320.1 70 81 51 12 320.1 125 81 59 10Methamidophos 142 94 54 20 5 142 125 54 19 7Methiocarb 226.1 169.1 61 13 11 226.1 121.1 61 27 8Methomyl 163.1 88.1 35 12 6 163.1 106 35 13 6Methoxyfenozide 369.1 149.1 56 24 9 369.1 313.2 56 13 10Metobromuron 259 170.2 56 23 4 259 148.2 56 21 4Mevinphos-E 225.1 127.1 51 20 7 225.1 193.2 51 10 10Mevinphos-Z 225 127 51 20 7 225 193.1 51 10 10Mexacarbate 223.2 166.1 64 23 10 223.2 151 64 35 9Monocrotophos 224.1 127.1 53 23 10 224.1 98 53 17 5Monolinuron 215.1 126.1 51 23 5 215.1 99 51 41 5Moxidectin 640.5 528.5 61 12 16 640.5 498.5 61 17 16Myclobutanil 289 70 71 37 12 289 125 71 47 8Novaluron 493 158.1 71 27 5 493 141.1 71 69 5Nuarimol 315 252.1 75 31 13 315 81 75 44 12Omethoate 214 124.9 46 29 5 214 182.8 46 17 5Oxadixyl 279.1 219.1 61 17 13 279.1 132.1 61 43 21Oxamyl + NH4 237.1 72.1 36 25 5 237.1 90.1 36 12 6Paclobutrazol 294 70 62 46 10 294 125 58 49 8Pencycuron 329.1 125 76 37 22 329.1 218.1 76 25 14Phenmedipham 301.1 136 50 26 5 301.1 168.1 50 14 4PhorateSulfone 293.1 97.1 36 41 5 293.1 171.1 36 17 5Picoxystrobin 368 145 56 27 4 368 205 56 15 4PiperonylButox + NH4 356.2 177.2 49 22 9 356.2 119.1 49 46 8Pirimicarb 239.2 72.1 64 35 10 239.2 182.1 64 23 10Prochloraz 376 308 45 17 10 376 70 45 44 12Promecarb 208.1 109 37 23 8 208.1 151 37 13 10Propamocarb 189.2 102 60 25 8 189.2 144 61 19 13Propargite + NH4 368.2 231.1 46 15 13 368.2 175.1 46 23 12Propiconazole 342.1 159 62 40 9 342.1 69 62 36 10Propoxur 210.1 111 39 19 6 210.1 168.1 39 11 10Pymetrozine 218 105 71 27 5 218 78 71 47 5Pyracarbolid 218.1 125 59 27 8 218.1 97 59 40 14

2400 K. Tran et al. / Food Chemistry 134 (2012) 2398–2405

Table 1 (continued)

Compound Transition 1 Transition 2

Q1 Q2 DP CE EXP Q1 Q2 DP CE EXP

Pyraclostrobin 388 194 31 19 5 388 163 31 29 5Pyridaben 365 147 46 31 5 365 309 46 19 5Pyrimethanil 200 107 71 33 5 200 82 71 35 5Pyriproxyfen 322 96 45 21 5 322 185 45 29 5Rotenone 395.1 213.1 90 32 12 395.1 192.1 90 34 10Siduron 233.3 137.2 66 21 5 233.3 94 66 31 5SpinetoramA 748.5 142.2 86 45 8 748.5 98.1 86 109 18SpinetoramB 760.5 142.2 96 41 10 760.5 98.1 96 101 18SpinosynA 732.5 142.2 111 43 10 732.5 98.1 111 103 16Spirodiclofen 411.3 313.3 72 23 8 411.3 71.3 71 33 10Spiromesifen 371.2 273.2 73 16 6 371.2 255.2 74 33 4Spiromesifen + NH4 388.2 273.2 41 19 12 388.2 255.2 41 39 16Spirotetramat 374.2 330.2 66 23 8 374.2 302.2 66 25 20Spiroxamine 298.2 144.2 72 28 10 298.2 100.1 72 46 14Sulfentrazone 387 307.1 81 27 5 387 146 81 57 5Tebuconazole 308.2 70 81 49 11 308.2 125 81 51 8Tebufenozide 353.2 133 54 24 9 353.2 297.2 54 14 9Tebuthiuron 229.1 172.4 46 21 5 229.1 116.1 46 35 5Teflubenzuron 381.1 141.2 66 52 5 381.1 158.2 66 23 5Temephos 467 419.1 101 29 12 467 405 101 23 12Thiabendazole 202.1 175.1 84 35 10 202.1 131.2 84 45 8Thiacloprid 253 126 68 30 9 253 99 68 60 14Thiamethoxam 292 211 64 18 10 292 181 64 32 10Thidiazuron 221.1 102.1 57 28 6 221.1 128.2 57 22 7Thiophanate-methyl 343 151.1 61 29 14 343 311 61 17 10Triadimefon 294 197.1 63 22 12 294 225 63 19 8Triadimenol 296.1 70 46 31 12 296.1 227.1 46 19 14Trichlorfon 256.9 109.1 66 25 20 256.9 127 66 25 8Tricyclazole 190 163 81 33 10 190 136 81 41 11Trifloxystrobin 409 186 31 23 5 409 206 31 21 5Triflumizole 346.1 278.1 51 15 8 346.1 73 51 27 6Triflumuron 359.1 156.2 52 23 6 359.1 139 52 44 6Triticonazole 318.1 70 63 42 10 318.1 125 63 41 8Vamidothion 288 146 61 19 10 288 118 61 33 10Zoxamide 336.1 187 55 33 11 336.1 159 53 39 12

Table 2UFLC parameters for LC–MS/MS.

Equilibration time (min) 0.1

Injection volume (lL) 2.0Total flow: (mL/min) 0.4Rinsing volume (lL) 500Rinsing speed (lL/s) 35Sampling speed (lL/s) 15Cooler temperature (�C) 15Column oven temperature (�C) 50

K. Tran et al. / Food Chemistry 134 (2012) 2398–2405 2401

2. Materials and methods

2.1. Materials

Brazilian açaí berries were bought in a supermarket in Belém –state of Pará. These establishments prepared acaí (in three forms)in strict hygienic conditions that are monitored by the Ministryof Agriculture. In the process, the fruit was washed and disinfectedwith chlorinated water, then transferred to pulpers to remove theedible portion (pulp + peel). Drinking water was added to obtainthe Açai Grosso, Médio or Popular. All machinery was made ofstainless steel. Shortly after obtaining the product, they were pack-aged in plastic bags and exposed for sale in the refrigerated sec-tions of stores. Shortly after buying the acaí samples, they werestored at �18 �C. Once frozen, the samples were flown (approxi-mately 4 h flight) to Rio de Janeiro, where they were subjected tolyophilisation and sent to the FDA lab in Lenexa, Kansas. Thesesamples do not have any chemical additives (preservatives, colour-ing agents, acids or emulsifiers). Dietary supplements labelled ascontaining cordyceps plus reishi, açaí, goji, mangosteen, noni,pomegranate and sea buckthorn were purchased over the Internetand in local grocery stores in Kansas and Missouri. Pesticide stan-dard mixes were purchased from AccuStandards (New Haven, CT).They consist of nine mixtures of 20–25 analytes (total of 174compounds) at 100 lg/mL in methanol (99.99%, HPLC grade,Honeywell, B&J Brand). The concentration for the stock standardmixture was 3.0 lg/mL in methanol. The intermediate standardhad a concentration of 100 ng/mL in methanol, as final concentra-tion for injected standard is 50.0 ng/mL in LC–MS buffer A (4 mMof ammonium formate and 0.1% formic acid in water). Spike

solution was prepared by dissolving 10 mg of high purity standards(obtained from the Environmental Protection Agency) in methanolto give a concentration of 1.0 mg/mL. It was then further diluted toconcentration of 3 lg/mL in acetonitrile (99.98% HPLC grade,Honeywell, B&J Brand).

2.2. Methods

Samples were prepared according to the QuEChERS method(Anastassiades, Lehotay, Štajnbaher, & Schenck, 2003; Lehotay,Mastovská, & Lightfield, 2005), that was recently validated in an in-ter-laboratory study (Sack et al., 2011). QuEChERS pre-filled centri-fuge tubes were from UCT Enviro-Clean (Bristol, PA). Theycontained 6 g anhydrous magnesium sulphate (MgSO4) plus 1.5 gNaCl (UCT Enviro-Clean # ECMSSC50CTFS), 1200 mg anhydrousMgSO4, plus 400 mg primary and secondary amine (PSA) sorbent(UCT Enviro-Clean # ECMS12CPSA415CT), and 150 mg anhydrousMgSO4 plus 50 mg PSA (UCT Enviro-Clean # CUMPS2CT). The

Table 3GC–MS (SIM mode) analytes, retention times (RT), ions and limits of quantitation (LOQs).

Compound RT (min) LOQ (lg/g) Quantitaion ion (m/z) Confirmation ions (m/z)

Metaldehyde 5.54 0.007 89 45, 87, 117, 131Phenmedipham (fragment 1) 5.95 0.08 133 104, 132, 134Propoxur C2H3NO 7.52 152 110D8-naphtalene (IS) 7.80 136 108, 134, 137Ethiolate 7.90 0.004 161 72, 100, 118Isoproturon fragment 8.35 0.002 146 128, 147, 161Bendiocarb C2H3NO 9.02 166 126, 151Carbofuran C2H3NO 9.45 164 122, 131, 149EPTC/Eptam 10.46 0.004 189 128, 132, 160Biphenyl 11.04 0.002 154 152, 153, 155Dioxacarb C2H3NO 11.74 166 121, 122, 165Butylate 11.82 0.004 174 146, 156, 217Vernolate 12.22 0.014 203 128, 132, 161Propham 12.53 0.007 179 119, 120, 137Pebulate 12.53 0.01 203 128, 132, 161Metolcarb 12.57 0.023 108 107, 109D10-acenaphthene (IS) 13.08 164 160, 162, 163THPI 13.36 0.043 151 79, 122, 152o-Phenylphenol 13.83 0.002 170 115, 141, 169, 171Carbaryl C2H3NO 13.81 144 115Tebuthiuron 13.92 0.037 156 129, 157, 171Isoprocarb 14.21 0.042 136 107, 121, 193Molinate 14.31 0.017 187 126, 127, 158Fenobucarb 15.80 0.007 150 107, 121, 151Propoxur 15.87 152 110, 209Diphenylamine 16.30 0.001 169 167, 168, 170Cycloate 16.47 0.011 154 83, 155, 215Phenmedipham (fragment 2) 16.95 0.08 167 108, 135, 1362,3,5-Trimethacarb 17.02 0.008 136 121, 135, 137MBTZ 17.28 0.006 164 108, 135, 136Bendiocarb 17.41 0.005 166 126, 151, 223Tebutam 17.61 0.007 190 134, 142, 233Promecarb 17.85 0.007 150 135, 136, 151Desmedipham 18.90 0.034 181 122, 135, 1363,4,5-Trimethacarb 18.79 0.011 136 121, 135, 137Ethoxyquin 18.84 0.006 202 145, 174, 217Carbofuran 19.00 0.022 164 122, 131, 165Prometon 19.10 0.003 225 168, 183, 210Bufencarb-1 19.28 0.017 164 107, 135Terbumeton 19.55 0.005 210 169, 211, 225Aminocarb 19.64 0.006 208 136, 150, 151Isocarbamib 19.80 0.010 142 113, 130Cycluron 19.84 0.019 198 127, 154, 169Pyrimethanil 20.35 0.015 198 184, 199Bufencarb-2 20.64 0.017 121 107, 122, 164Fenfuram 20.83 0.010 201 109, 110Mexacarbate 20.86 0.011 165 150, 164, 222Secbumeton 20.94 0.004 196 169, 210, 225Octhilinone 21.50 0.020 213 101, 114, 196Ethiofencarb 21.65 0.019 168 107, 108, 139Pirimicarb 21.36 0.003 238 72, 166, 167Dioxacarb 21.99 0.009 166 121, 122, 165Desmethryn 22.08 0.004 213 171, 198, 214Metribuzen 22.37 0.016 198 144, 199, 214Beta-Spiroxamine 22.53 100 144, 1983-Hydroxycarbofuran 22.54 0.011 180 147, 151, 162Cymiazole 22.77 0.005 218 144, 170, 185Fuberidazole 22.79 0.009 184 155, 156, 183Carbaryl 22.87 0.010 144 115, 145Simetryn 22.90 0.006 213 170, 185, 198Ametryn 23.10 0.001 212 170, 185, 227Kresoxim-methyl 23.15 0.015 223 116, 194Metalaxyl 23.01 0.006 249 206, 162, 234Prometryn 23.30 0.003 241 184, 199, 226Naphthalene acetamide 23.63 0.007 185 115, 141Alpha-Spiroxamine 23.75 100 144, 198Ethofumesate 23.93 0.006 286 161, 179, 241Terbutryn 23.81 0.004 226 170, 185, 241Methiocarb 23.88 0.004 168 153, 169, 225Norea 24.15 0.022 153 150, 154, 222Chlorpyrifos 24.49 0.006 314 199, 208, 210Diethofencarb 24.80 0.007 225 168, 196, 267Fenpropimorph 24.81 0.011 128 129, 173, 303Methfuroxan 25.07 0.011 229 137, 138, 230

2402 K. Tran et al. / Food Chemistry 134 (2012) 2398–2405

Table 3 (continued)

Compound RT (min) LOQ (lg/g) Quantitaion ion (m/z) Confirmation ions (m/z)

Desmethyl diphenamid 25.22 0.005 167 165, 166, 168Tetraconazole 25.19 0.015 336 171, 254, 338Nitrothal isopropyl 25.36 0.005 254 212, 236, 237Butralin 25.37 0.009 266 250, 267, 295Diphenamid 25.50 0.004 167 165, 166, 239Pyracarbolid 25.62 0.017 217 97, 125Isopropalin 25.82 0.006 280 238, 264, 281Pendimethalin 26.03 0.018 252 253, 281Cyprodinil 26.10 0.004 224 210, 225MGK-264 26.17 0.008 164 111, 165, 275Allethrin-1 26.60 0.015 123 107, 136, 168Thiabendazole 26.80 0.056 201 130, 174Allethrin-2 26.85 0.015 123 107, 136, 168Furalaxyl 26.88 242 152, 225, 301Aniten 27.33 0.006 181 152, 282Napropamide 28.45 0.062 171 128, 271Tricyclazole 28.91 0.034 189 162, 190Isoprothiolane 28.88 0.008 290 189, 204, 231Carboxin 29.54 0.028 235 132, 143Buprofezin 29.47 0.011 305 172, 175, 190Flusilazole 29.47 0.042 233 123, 315Methoprotryne 29.81 0.018 256 171, 214, 271Pyrethrin-1 29.77 0.120 123 150, 168Bupirimate 29.56 0.009 273 166, 208, 316Diniconazole 30.78 268 156, 232, 270Oxadixyl 30.97 0.019 163 132, 233, 278Mepronil 31.78 269 119, 210Pyrethrin-2 32.05 0.120 123 133, 162Benalaxyl 32.04 0.009 148 206, 266, 325Lenacil 32.63 0.030 153 136, 154, 234Hexazinone 32.98 0.025 171 128, 172, 252Sethoxydim 33.45 0.120 178 191, 204, 252Prorpargite 33.46 0.026 350 173, 201, 335Piperonyl butoxide 33.77 0.014 176 177, 193, 338Resmethrin-1 33.63 0.012 171 128, 143, 338Resmethrin-2 33.90 0.012 171 128, 143, 338Nitralin 33.92 0.011 316 274, 300D12-Chrysene (IS) 34.60 240 236, 241Tetramethrin-1 34.55 0.019 164 107, 123, 165Carbosulfan 34.41 0.028 160 118, 164, 323Fenoxycarb 34.91 0.053 186 255, 256, 301Tetramethrin-2 34.86 0.019 164 107, 123, 165Fenpropathrin 35.04 0.020 265 181, 208, 209Fenazaquin 35.28 0.033 160 117, 145

D-Phenothrin 35.68 0.010 183 123, 184, 350

Pyriproxifen 36.07 0.019 226 136, 137Tralkoxydim 36.22 0.078 283 137, 226, 268Amitraz 36.36 0.500 293 132, 161, 162Naproanalid 36.66 0.004 291 144, 171, 292Biteranol-1 37.37 0.007 170 112, 168, 171Biteranol-2 37.52 0.007 170 112, 168, 171Etofenprox 38.96 0.027 163 135, 183, 376.1Azoxystrobin 41.06 0.008 344 345, 372, 388, 403Famaxadone 41.39 330 196, 224, 315

IS means internal standard.

Table 4Pesticides (ng/g) found by LC–MS/MS in samples obtained in the USA and the Internetthat were labelled as containing Açaí.

Pesticide residues Açaí 1 Açaí 4 Açaí 8 Açaí 9 Açaí 10

Bifenazate 1.6Boscalid 2.6 2.5 3.0Carbendazim 0.9Hexythiazox 0.6Imidacloprid 0.9Metalaxyl 0.2Methoxyfenozide 0.2 3.8Pyraclostrobin 0.1

K. Tran et al. / Food Chemistry 134 (2012) 2398–2405 2403

QuEChERS procedure was done as follows. For most samples, 15 gof sample was added 15 mL of acetonitrile (CH3CN) in a 50 mL cen-trifuge tube, but in some samples, 10 g of sample was added 10 mLof CH3CN. The volume was adjusted to maintain ratio of 1 g sampleper mL of CH3CN. That is, for 5 ml spike volume add 10 mL CH3CNto 15 g sample. This was shaken for 1 min in Geno/Grinder (SpexPrep model 2000) at 1000 strokes/min. Then, the anhydrous MgSO4

plus NaCl was added. For 15 g samples, 6 g MgSO4 + 1.5 g NaCl wasadded and for 10 g sample 4 g MgSO4 + 1 g NaCl was added. Thiswas spiked to obtain 2–1000 lg/mL concentrations of analytes.This was shaken again for 1 min at 1000 strokes/min, then centri-fuged (Multifuge X3R, Thermo Scientific) at about 4500 rpm for5 min. The supernatant was cleaned up using the PSA sorbent. Thatis, 1.0 mL of the extract was transferred to a 2 mL centrifuge tubecontaining 50 mg PSA + 150 mg MgSO4. Then, 0.5 mL of the extract

was diluted to 1.0 mL with LC–MS aqueous buffer A (0.5 g sample/mL), filtered through a 0.45 lm nylon filter and analysed by LC–

XIC of +MRM (364 pairs): 142.0/94.0 amu Expected RT: 1.9 ID: Methamidophos.1 from Sample 17 (200) o... Max. 1.5e5 cps.

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.02 81 165 255 345 426 499 590 680 761 876 995 1916 3033

Time, min

0.0

2.0e5

4.0e5

6.0e5

8.0e5

1.0e6

1.2e6

1.4e6

1.6e6

1.8e6

2.0e6

2.2e6

2.4e6

2.6e6

2.8e6

3.0e63.1e6

Inte

nsity

, cps

1.88

KAN 200 ng/mL

Fig. 1. Separation of pesticide standards by LC–MS/MS.

2404 K. Tran et al. / Food Chemistry 134 (2012) 2398–2405

MS. The solvent was removed from the remaining 0.5 mL, so that itcould be redissolved in a solvent suitable for GC–MS/MS.

The LC–MS/MS was an AB Sciex (Foster City, CA) 4000 QTrap:scheduled MRM in the positive ionisation mode. Both quantitativeand confirmatory ions were used in each pesticide identification.The transition parameters and MS parameters are listed in Table 1.

The prominent Ultrafast Liquid Chromatography (UFLC) wasfrom Shimadzu (Kyoto, Japan). It had a LC-20AD Pump, Sil-20ACAutosampler, DGU-20A3 Online Degasser, and CTO-20AC Columnoven set at 40 �C. Pesticides were analysed using a Waters AtlantisT3 octadecyl silica (C18) column (2.1 � 0100 mm, 3 lm). Buffer A(4 mM of ammonium formate and 0.1% formic acid in water) andbuffer B (4 mM of ammonium formate and 0.1% formic acid in ace-tonitrile) was used as mobile phases. The UFLC parameters and thegradient elution program are listed in the Table 2.

GC with element-specific detectors was used to look for 40organohalogen compounds (OHs), and 65 organophosphorus com-pounds (OPs) using a Varian 3600 GC with an 8000 series autosam-pler. They were separated on a DB-17 column (30 m � 0.53 mm ID,film thickness 1.5 lm). The OHs were detected by an electrolyticconductivity (ELCD) detector with a base temperature of 300 �Cand a reaction temperature of 900 �C. The ELCD reaction gas wasH2, flowing at 80 mL/min, with n-propanol solvent and a vent timeof 1 min. The oven temperature started at 120 �C and increased at5 �C per min until it reached 280 �C, where it was held for 3 min.The OPs were detected using a pulsed flame photometric detectorPFPD. The detector base temperature was 300 �C. Hydrogen and airflow rates were 10–15 mL/min.

Another 117 compounds were detected by GC–MS in theselected ion mode (SIM) using an Agilent Model 6890 GC with amodel 5973 mass selective detector and Agilent Chem Stationsoftware. The temperatures of the source, quadrupole and transferline were 250, 150 and 290 �C, respectively. The analytes with

retention times, ions and limits of quantitation are in listed in Ta-ble 3. The GC inlet system contained a 4 mm glass injector liner,Agilent part # 5181–3316. The inlet temperature was 280 �C.Pulsed splitless injection with a 50:1 split ratio at 1.0 min wasused. The injection volume was 2 lL. The carrier gas was ultrapurehelium. The column was a DB-5 phase, 0.25 mm ID � 30 m DB-5phase, with a 0.25 lm film thickness. The oven temperature pro-gram was: Initial temperature: 50 �C, increased at 10 �C/min to130 �C, then 4 �C/min to 230 �C, then hold 7 min for a total runtime of 46 min.

GC–MS and GC–MS/MS were used to look for 213 pesticides andindustrial chemicals. The method was based on a published meth-od (Wong et al., 2010). They were analysed on an Agilent 7890A GCwith 5975C inert XL MSD with Triple-Axis Detector. The data werereviewed using an RTL database of 930 compounds and pesticidessearched using the NIST/EPA/NIH Mass Spectral Library Version2.0f, build October 8, 2008.

The samples were also analysed on an Agilent 7890A GC with7000 GC/MS Triple Quad set up for 213 compounds. The names ofthe analytes are in the Supplementary Information. Two HP-5MSUI 15 m � 0.25 mm ID columns with 0.25 lm film thickness wereused in series. They were installed with a back flush component be-tween the two columns. This gives the second column a slightlyhigher flow rate (1.2 mL/min, compared to 1.0 mL/min) than thefirst column. There was a single taper 2 mm id dimpled liner, a300 �C transfer line and a 300 �C electron source. The temperatureof both the first and third quadrupoles was 180 �C. The column oventemperature started at 60 �C, where it was held for 1 min, followedby a 40 �C/min increase to 170 �C, then increase 10 �C/min untilreaching 310 �C. The inlet temperature started at 60 �C, where itwas held for 0.2 min, then increase 600 �C/min until reaching270 �C. There was a back flush at 4 mL/min for 2 min at 300 �C atthe end of the run. The names of the analytes are in Table 3.

Table 5Pesticides found by LC–MS/MS in Other Fashionable Fruit Juices (ng/g).

Pesticide residues Goji 1 Goji 2 Mangosteen Pomegranate Mixturea

3-Hydroxycarbofuran 0.2Acetamiprid 3.0 4.4Azoxystrobin 0.3Boscalid 0.5Carbofuran 0.1Diflubenzuron 0.3DimethomorphA 6.4DimethomorphB 13.9Fenhexamid 6.3Fludioxonil 89.2 3.4Flusilazole 0.6Imazalil 4.7Imidacloprid 1.8 0.6 1.1Iprovalicarb 3.6Metalaxyl 0.1 0.6Methoxyfenozide 0.2Propamocarb 0.3Pyridaben 0.1Pyrimethanil 13.5Tebufenozide 0.2Thiabendazole 2.7

a The label on the sample labelled mixture said it had several juices, includingAçaí.

Table 6Spike recoveries in LC–MS/MS.

Samples Spike compounds % Recovery

Sea Buckthorn (Matrix blank) (No methomyl found)Sea Buckthorn Spike Methomyl 86Sea Buckthorn Spike Duplicate Methomyl 91Goji 3 (Matrix blank) (No methomyl found)Goji 3 Spike Methomyl 94Goji 3 Spike Duplicate Methomyl 95Genuine Brazilian Açaí Grosso (Matrix blank) (No methomyl found)Genuine Brazilian Açaí Popular Methomyl 70Genuine Brazilian Açaí Médio Methomyl 76Genuine Brazilian Açaí Grosso Methomyl 80

K. Tran et al. / Food Chemistry 134 (2012) 2398–2405 2405

3. Results and discussion

A chromatogram of showing the separation of standards is inFig. 1. None of the 174 pesticides that we looked for by LC–MS/MS were found in genuine açaí from Brazil or in USA açaí samples2, 3, 6, 7, 11, 13 and 14. The names of the pesticides are in Table 1.The same samples and numbering system were used in the accom-panying paper on the NMR analysis of lipids in açaí (Luo, Tran,Levine, Sabaa-Srur, & Smith, 2011). Likewise, no pesticides werefound in one sample each of cordyceps plus reishi, sea buckthornand noni. However, pesticides were found in five samples labelledas containing açaí. The amounts found are listed in Tables 4 and 5.Pesticides were also found in two samples labelled as goji juice,one sample labelled as mangosteen juice, one sample labelled aspomegranate juice and a sample labelled as containing a mixtureof juices, including açaí. Most pesticide residues found were far be-low the tolerance levels (1–6 lg/g, depending on the pesticide).However, there is zero tolerance for boscalid, dimethomorph, ipro-valicarb, pyridaben, pyrimethanil, and imazalil (The PesticideChemical News Guide, 2010), which were found in some samples.Imidacloprid was found in samples labelled as containing mango-steen, goji, and the sample labelled as containing a mixture of fruitjuices. On the other hand, metalaxyl was only found in mangosteenand the sample containing a mixture of fruit juices. There is zero

tolerance for both metalaxyl and imidacloprid in goij and mango-steen (The Pesticide Chemical News Guide, 2010). The sample la-belled as containing a mixture of fruit juices had the greatestnumber of pesticide residues found, ranging from 0.2 to 13.9 ng/g. Pesticides found in this sample were well below the allowed lev-els. The highest pesticide level was found in the pomegranate juicesample, i.e. 89.2 ng/g of fludioxonil, far below the tolerance level inpomegranate of 5.0 lg/g (The Pesticide Chemical News Guide,2010). Three samples of genuine Brazilian açaí and one sampleeach of goji and sea buckthorn were spiked with methomyl. Spikerecoveries were from 86% to 101% (Table 6). Ion ratios agreed wellbetween the spikes and standards.

Also, none of the 213 pesticides and industrial chemicals thatwere analysed for by GC and GC–MS/MS were found in the Brazil-ian açaí samples.

In conclusion, pesticides were found in 10 of the 21 samplesthat were analysed. Pesticides were not found in genuine Brazilianaçaí. So, the presence of pesticides in samples obtained in the USAand labelled as containing Brazilian açaí probably indicates thatthey were adulterated.

This work should not be taken as reflecting FDA policy orregulations.

Appendix A. Supplementary data

Supplementary data associated with this article can be found, inthe online version, at http://dx.doi.org/10.1016/j.foodchem.2012.04.034.

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