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PerkinElmer: The Determination of Benzene, Toluene, Ethyl Benzene, Xylenes and Styrene in Olive Oil...

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  1. 1. The Determination ofBenzene, Toluene, EthylBenzene, Xylenes and Styrene in Olive Oil using HS Extraction and GC/MS Andrew Tipler Chromatography R&D ManagerPerkinElmer Inc., Shelton, CT 2009 PerkinElmer2012
  2. 2. Olive OilOlive oil is produced by grinding olives andextracting the oil by mechanical (pressing) orchemical (solvent extraction) means.Olive oil is composed mainly of the mixedtriglyceride esters of oleic acid and palmiticacid and of other fatty acids, along with tracesof squalene and sterols.It is commonly used in cooking, cosmetics,pharmaceuticals, and soaps and as a fuel.
  3. 3. Olive Oil ProductionAnnual perProduction in Production % ConsumptioncapitaCountry tons (2009) (2009) (2005) consumption (kg) World2,907,985100% 100% 0.4 Spain1,199,20041.2%20% 13.6Italy 587,70020.2%30% 12.4Greece332,60011.4% 9% 23.7Syria 168,1635.8%3%7.0 Tunisia150,0005.2%2% 11.1 Turkey 143,6004.9%2%1.2Morocco95,3003.3%2%1.8Portugal 53,3001.8%2%7.1 France6,300 0.2%4%1.3United States2,700 0.1%8%0.6 Others 169,1225.8% 18%1.2 Source: Wikipedia.com
  4. 4. Effects of Air PollutionOlive trees are good at absorbing air pollutants and passing them on to theolives and thus into the oil
  5. 5. Acceptable limits for BTEXS in olive oilConcentrations in olive oil were found to be around several tens of g/kg forbenzene; a few hundred g/kg for toluene and many hundreds of g/kg for thesum of ethyl benzene and xylenes. Substantial concentrations of styrene werefound which however was probably of natural origin. The situation wasconsidered to be sufficiently serious that a definition of provisional limits forthese components was proposed (benzene: 50g/kg; toluene: 180g/kg; ethylbenzene: 50g/kg; xylenes: 280g/kg). However, these were not imposed as aconsequence of disagreement in the European Union . Maurus Biedermann,Konrad Krob, Gianni Morchio, Z Lebensm Unters Forsch (1995) 200; 266-272.Despite the strong concerns, even today, there still appears to be noagreement on the acceptable limits of BTEXS in olive oil.On 10 June 2011, the US National Toxicology Program has described styreneas "reasonably anticipated to be a human carcinogen".
  6. 6. BTEXS (~0.6ng) separation using GC/MS Styrene 30m x 0.25mm x 1.0m Elite-Wax o-Xylene Scan EI+9.92TIC100 35(1)-10-130(0) Ethylbenzene 1.17e8p-Xylene m-Xylene Toluene 8.85 7.94 8.07Benzene 6.635.24 %4.92 5.004.62 4.726.49 0Time 5.05 5.55 6.056.557.05 7.558.058.559.05 9.5510.05
  7. 7. Sampling Olive Oil Olive oil is a heavy sample matrix and is not very GC- friendly. Direct injection will cause problems with breakdown and Dont do this in your lab! contamination. Some form of extraction technique is required to separate the BTEXS from the sample matrix prior to introduction into the GC.
  8. 8. Headspace SamplingHeadspace sampling provides a very easyway to extract the volatile BTEXScompounds from the olive oil matrix.10g of sample are placed in a vial which isthen sealed with a cap and maintained at90C for 20 minutes. The volatilecomponents (including BTEXS) willpartition into the vapor phase0.15mL of the vapor phase is transferredto the GC column for analysis.
  9. 9. Analytical SystemClarus SQ8 GC/MS TurboMatrix HS Sampler
  10. 10. Pressure-Balanced Headspace Sampling EquilibrationPressurization SamplingV2 V1V1 V1PHSValveclosed forjust a few secondsOlive oilsample
  11. 11. Total Ion Chromatogram from Spiked Olive Oil 1: Scan EI+Ethanol100TIC10g olive oil spiked with 17ng/g BTEXS1.17e830m x 0.25mm x 1.0m Elite-Wax35(1)-10-130(0)Ethylbenzene p-Xylene Toluenem-XyleneBenzene o-XyleneStyrene % 6.577.214.624.63 4.91 5.70 7.978.345.916.29 10.438.21 6.068.91 0 Time5.055.55 6.056.557.057.558.05 8.559.05 9.5510.05
  12. 12. Single Ion Monitoring Improves Selectivity and Detectability9.93 100 2.61e4 Styrene SIM @ 104 Daltons%0Ethylbenzenep-Xylene 8.17 m-Xylene 100 9.38e3 SIM @ 106 Daltons o-Xylene 7.94 8.078.86%0 6.62Toluene 100 4.80e4 SIM @ 92 Daltons%05.24 100 Benzene 6.95e4 SIM @ 78 Daltons%0Time 5.105.60 6.10 6.60 7.10 7.608.108.60 9.10 9.6010.10
  13. 13. SiFi Enables Simultaneous Full and Single Ion Data collection
  14. 14. 0% 1005.10 OliveOilAStd_060Benzene @ 78 Da5.606.106.60Toluene @ 92 Da7.107.60Ethylbenzene @ 106 Da8.10p-Xylene @ 106 Dam-Xylene @ 106 Da8.60o-Xylene @ 106 Da9.10SIM of Olive oil spiked with 17ng/g BTEXS9.609.95 Styrene @ 104 Da10.10Time
  15. 15. Extracted Calibration Plot for Benzene 18000y = 178.38x - 60.006 16000 R = 0.9998 14000 12000Peak Area (Counts) 1000080006000400020000 0 10 20 3040 50 6070 80 90 100Concentration (ppb w/w)
  16. 16. Extracted Calibration Plot for Styrene 1200 y = 12.021x - 3.8872R = 0.9997 1000 800Peak Area (Counts) 600 400 200 00 10 20 3040 50 60 7080 90 100 Concentration (ppb w/w)
  17. 17. Quantitative PerformanceRSD r2Limit of Detection Compound (% at 45ng/g, n=10) (from 4.5 to 90ng/g) (ng/g)Benzene1.7 0.99980.1Toluene3.8 0.99860.2Ethylbenzene 2.3 0.99950.3p-Xylene 3.5 0.99970.3m-Xylene 3.7 0.99980.3o-Xylene 3.3 0.99950.3Styrene3.5 0.99970.3Standard mixtures prepared in 10g clean olive oil
  18. 18. Low-Level Determination of BTEXS in Olive Oil S/N:RMS=23.81 TIC100 1.84e3 Styrene, 3.1ng/g10.039.71 9.80 10.17 % 0 S/N:RMS=39.67 TIC100 2.47e3m-Xylene, 5.4ng/g 8.85 % 8.347.93 8.06 8.578.93 9.057.73 7.80 0 S/N:RMS=71.15 TIC100 1.10e4Toluene, 5.9ng/g % 0S/N:RMS=14.84TIC100 3.90e3Benzene, 0.9ng/g5.015.42 % 0 Time5.10 5.60 6.10 6.607.10 7.60 8.10 8.609.109.6010.10
  19. 19. Background from Clean Olive Oil Toluene @ 92 DaBenzene @ 78 Da Clean Olive Oil spiked with 17ng/g BTEXSOliveOilAStd_060100Ethylbenzene @ 106 Dam-Xylene @ 106 DaStyrene @ 104 Dap-Xylene @ 106 Da o-Xylene @ 106 Da%9.9505.10 5.60 6.10 6.60 7.10 7.60 8.10 8.60 9.10 9.60 10.10 TimeClean Olive OilOliveOilA_061100% 0 Time 5.10 5.60 6.106.60 7.10 7.608.10 8.60 9.109.6010.10
  20. 20. BTEXS in Olive Oil from Local Supermarket (ng/g) Ethylbenzene Sample Source m-Xylene p-Xylene o-Xylene BenzeneToluene StyreneCalifornia 0.895.86 1.661.455.243.77 3.07Italy, Greece, Spain Tunisia 2.8627.556.125.8616.73 8.7541.34Italy, Spain, Greece, Tunisia3.0724.2213.47 7.8523.64 13.97 39.59Italy, Spain, Tunisia, Turkey, 2.9917.033.743.449.356.1440.09ArgentinaSpain, Argentina 2.4334.997.227.4218.97 10.65 126.11Italy, Spain, Greece, Tunisia, 4.0935.7119.13 17.10 59.31 28.10 61.05Morocco, Syria, TurkeyItaly, Greece, Spain, Tunisia1.252.79ND 1.803.743.17 7.39
  21. 21. Conclusions The sensitivity of the MS detector in SIM mode enables detection of low levels of BTEXS with standard headspace sampling. Detection limits of 0.1 to 0.3ng/g have been demonstrated which compare favorably against those in other published papers (~5ng/g). The HS sampling system simplifies sample preparation and eliminates the effects from a heavy sample matrix entering the chromatographic column and the MS detector. Good quantitative performance has been shown. Significant levels of BTEXS were found in olive oils purchased at a local (Connecticut) supermarket.
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