Analysis of MCPD- and Glycidyl- Esters in edible oils

Transcription

1 Analysis of MCPD- and Glycidyl- Esters in edible oils IZMIR, TURKEY Dubois Mathieu Nestlé-Research-Center Quality and Safety

2 Agenda 2

3 MCPD- and glycidyl-esters Esters of Mono-Chloro-Propane-Diol H ccurrence: H thermally processed foods vegetable fats/oils (Highest amounts in refined palm oil) R Concern: R R intrinsic toxicity release of 3-MCPD: - carcinogen - TDI of 2 µg/kg bw (EC, JECFA) - regulatory limit (EC): 2 µg/kg in HVP and soy sauce (CDEX limit of 4 µg/kg) release of 2-MCPD H 3-MCPD 3-MCPD diesters 3-MCPD monoesters H R R = alkyl currence: refined fats and oils (Highest amounts in refined palm oil) Concern: Esters of glycidol H 2 C intrinsic toxicity (unknown) release of glycidol: - genotoxic carcinogen - no safety limit H 2 C CH R R= alkyl Walburga Seefelder NRC-QS 3

4 Indirect analysis: questionable Hydrolysis Derivatization Analysis 2-MCPD 3-MCPD esters Glycidyl esters Alkaline MCPD 3-MCPD 2-MCPD 3-MCPD derivatized 2-MCPD 3-MCPD free Ease of use Precision impaired by: Already in place nly 2 chemical standards Hydrolysis (alkaline / acidic) Derivatisation 4

5 Hydrolysis Derivatisation Detection Method 7 indirect methods for MCPD and glycidyl-esters analysis H2S4/MeH NaCH3/MeH HFBI PBA in Na PBA in (NH4)2S4 HFBI PBA in Na PBA in (NH4)2S4 PBA in NaBr 3-MCPD 2-MCPD 3-MCPD 3-MCPD 3-MCPD 3-MCPD 3-MCPD 2-MCPD 3-MCPD Glycidol Nestlé Velisek et al. BfR (II) BfR (III) DGF CIII 18 A + B (from 3- MCPD- and glycidylesters) BfR (I) SGS 5

6 Agenda 6

7 MCPD and glycidyl esters are very similar in nature to TAG/DAG and MAG MCPD mono-esters MCPD di-esters Matrix esters of glycerol H H Sn1-3-MCPDmono-esters n n Sn2-3-MCPDmono-esters n1 n1 n2 n2 3-MCPDdi-esters 2-MCPDdi-esters H n1 n3 n1 n2 n2 TAG DAG H n Sn1-2-MCPDmono-esters glycidyl-esters (GE) n H H n1 MAG n=? Seefelder et al. Eur. J. Lipid Sci. Technol 113 (3), (211)

8 Which standards to match fatty acid composition of oils % Sunflower oil Soybean oil Safflower oil Palm Kernel oil Palm oil live oil Grape seed oil Corn oil Coconut oil Canola oil Linolenic acid Linoleic Acid leic acid Stearic acid Palmitic acid Myristic acid Lauric acid Capric acid Caprylic acid % 6% 8% 2 Not available as GEs and MCPD mono-esters analytical standards Rational approach for glycidyl- and MCPD-mono-esters 8

9 Which standards to match fatty acid composition of oils % Sunflower oil Soybean oil Safflower oil Palm Kernel oil Palm oil live oil Grape seed oil Corn oil Coconut oil Canola oil Linolenic acid Linoleic Acid leic acid Stearic acid Palmitic acid Myristic acid Lauric acid Capric acid Caprylic acid Glycidyl- esters: Glycidyl laurate (C12:) Glycidyl myristate (C14:) Glycidyl palmitate (C16:) Glycidyl stearate (C18:) Glycidyl oleate (C18:1) Glycidyl linoleate (C18:2) Glycidyl linolenate (C18:3) Same rational 7+7 standards 3-MCPD- mono- esters: 1-lauryl-3-MCPD (C12:) 1-myristyl-3-MCPD (C14:) 1-palmityl-3-MCPD (C16:) 1-stearyl-3-MCPD (C18:) 1-oleyl-3-MCPD (C18:1) 1-linoleyl-3-MCPD (C18:2) 1-linolenyl-3-MCPD (C18:3) 9

10 GE laurate GE myristate GE palmitate GE stearate GE oleate GE linoleate GE linolenate GE laurate GE myristate GE palmitate GE stearate GE oleate GE linoleate GE linolenate GE laurate GE myristate GE palmitate GE stearate GE oleate GE linoleate GE linolenate GE laurate GE myristate GE palmitate GE stearate GE oleate GE linoleate GE linolenate il samples follow this simple model 1% 8% 6% 4% 2% % GEs distibution in 13 palm oil samples measured theory 1% 8% 6% 4% 2% % GEs distibution in 4 coconut oil samples measured theory 1% 8% 6% 4% 2% % GEs distibution in 2 sunflower oil samples measured theory 1% 8% 6% 4% 2% % GEs distibution in 2 canola oil samples measured theory 1

11 Situation is even more complex with 3-MCPD diesters Theoretical example of palm oil: 3-MCPD-di-esters chemical standards to cover all possibilities: Theoretical abundance (3-MCPD FA1; FA2 ) = abundance (FA1) x abundance (FA2) n1 n2 3-MCPD di-esters Fatty acid (FA1 or 2) Abundance (% in palm oil) Lauric acid.2 Myristic acid 1 Palmitic acid 45 Stearic acid 4 leic acid 4 Linoleic Acid 1 Linolenic acid

12 Situation is even more complex with 3-MCPD diesters % Lauric acid Myristic acid Palmitic acid Stearic acid leic acid Linoleic Acid Linolenic acid Linolenic acid Linoleic Acid leic acid Stearic acid Palmitic acid Lauric acid Myristic acid Theoretical example of palm oil: 3-MCPD-di-esters chemical standards to cover all possibilities: 49 standards 1% 3-MCPD di-ester content (Theory) 25 Theoretical distribution 2 15 n1 1 5 n2 sn 1 FA 12

13 Situation is even more complex with 3-MCPD diesters % Lauric acid Myristic acid Pamitic acid Stearic acid leic acid Linoleic Acid Linolenic acid Linolenic acid Linoleic Acid leic acid Stearic acid Palmitic acid Lauric acid Myristic acid Theoretical example of palm oil: 3-MCPD-di-esters chemical standards to cover all possibilities: 49 standards 1% 3-MCPD di-ester content (Theory) 28 standards 1% 3-MCPD di-ester content (Experimental) 4 Theoretical distribution n n2 sn 1 FA 13

14 Situation is even more complex with 3-MCPD diesters % Lauric acid Myristic acid Pamitic acid Stearic acid leic acid Linoleic Acid Linolenic acid Linolenic acid Linoleic Acid leic acid Stearic acid Palmitic acid Lauric acid Myristic acid Theoretical example of palm oil: 3-MCPD-di-esters chemical standards to cover all possibilities: 49 standards 1% 3-MCPD di-ester content (Theory) 28 standards 1% 3-MCPD di-ester content (Experimental) 1 standards 98% 3-MCPD di-ester content (Pragmatic) 4 Theoretical distribution 35 il 3-MCPD di-esters coverage (1 standards included ) canola oil 93% corn oil 98% cotton seed il 96% grape seed oil 99% olive oil 95% palm oil 98% palm lein 96% safflower oil 99% soybean oil 9% sn 1 FA 14

15 Situation is even more complex with 3-MCPD diesters Theoretical example of palm oil: 3-MCPD-di-esters chemical standards to cover all possibilities: 49 standards 1% 3-MCPD di-ester content (Theory) 28 standards 1% 3-MCPD di-ester content (Experimental) 1 standards 98% 3-MCPD di-ester content (Rational) 6% Measured in 22 palm oil samples Theoretical in Palm oil 5% 4% 3% 2% 1% Approach confirmed by samples analysis % +LS PP LL+Ln L S PL P PS 15

16 Linolenic acid Linoleic Acid Caprylic acid Capric acid Lauric acid Myristic acid Palmitic acid Stearic acid leic acid Linoleic Acid Linolenic acid Caprylic acid Capric acid Lauric acid Myristic acid Palmitic acid Stearic acid leic acid % Issues with palm kernel and coconut oil Current available standards do not fit with: - Palm kernel oil 7.8% 3-MCPD di-ester coverage - Coconut oil 3.9% 3-MCPD di-ester coverage Theoretical distribution in palm kernel oil 25 2 Not available: custom synthesis required sn 1 FA 16

17 Quantitation requires standard addition or labeled standards Relative Abundance Relative Abundance Standard addition: compensate matrix effects External calibration: IS mandatory (custom synthesis) * * * * NL: n 1.85E4 C 21H H: 8 C 21H 39 3 p (gss, s/p:4) Chrg 1 6 R: 5 4 NL: 1.93E * * * * H n NL: 1.4E4 C 21H H: 8 C 21H p (gss, s/p:4) Chrg 6 1 R: 5 Res.Pwr NL: 1.46E * * * * * n1 NL: 1.17E4 C 37 n2h H: C 37 H p (gss, s/p:4) Chrg 1 R: 5 NL: 1.24E m/z m/z C C 4 H H: 8 C C 4 H 39 3 p (gss, s/p:4) Chrg 1 6 R: m/z m/z C C 4 H H: C C 4 H p (gss, s/p:4) Chrg 6 1 R: 5 Res.Pwr m/z m/z C C 5 H H: C C 5 H p (gss, s/p:4) Chrg 1 R: 5 17

18 Standard addition (on extracts) vs external calibration (labeled standards) Comparison if standard addition vs external calibration on Ges: 4 GEs with corresponding 4 GEs IS ( 13 C 3/4 ) 5 palm oil samples 1 Std addition on extracts (value in µg/kg) y = 1.66x R² =.9915 Glycidyl-palmitate Glycidyl-stearate Glycidyl-oleate Glycidyl-linoleate Glycidyl-linolenate Tolerance int. (95%) Linear (Y = X) Ext. Calib with IS (value in µg/kg) Conclusion: Few IS to check recoveries in each sample Standard addition on extracts 18

19 Agenda 19

20 Direct analysis of MEs and GEs : 3 methods developed Solubilization + IS (if available) Extraction Liquid chromatography Mass spectrometry Place text or Pictures here Place text or Pictures here Solvent compatible with extraction IS: check recoveries Method 1: GEs Method 2: MCPD mono-esters Method 3: MCPD di-esters C18 column TF, QTF: identification, method development QqQ: routine analysis

21 Chromatographic separation ToF detection Column: Waters Acquity HSS T3 (5x2.1mm, 1.8µm) Elution: A MeH:H2 75:25 (1mM ammonium formate,.1% HCH ) B: Isopropanol (1mM ammonium formate,.1% HCH) Run time: 15 min between injection System: Agilent UHPLC 129 and QToF 654 glycidyl-esters MCPDmono-esters glycidyl-laurate glycidyl-myristate glycidyl-linolenate glycidyl-linoleate glycidyl-palmitate glycidyl-oleate glycidyl-stearate 1 myristoyl-3-chloropropanediol 1 lauroyl-3-chloropropanediol 1 palmitoyl-3-chloropropanediol 1 stearoyl-3-chloropropanediol 1 oleyl-3-chloropropanediol 1 linoleoyl-3-chloropropanediol 1 linolenoyl-3-chloropropanediol MCPDdi-esters 1,2-bis-palmitoyl-3-chloropropanediol 1-palmitoyl-2-stearoyl-3-chloropropanediol 1,2-dilinoleoyl-3-chloropropanediol 1-oleoyl-2-stearoyl-3-chloropropanediol 1-linoleoyl-2-stearoyl-3-chloropropanediol 1-oleoyl-2-linolenoyl-3-chloropropanediol 1-oleoyl-2-linoleoyl-3-chloropropanediol 1-palmitoyl-2-linoleoyl-3-chloropropanediol 1,2-bis-oleoyl-3-chloropropanediol 1-oleyl-2-palmitoyl-3-chloropropanediol 21

22 MCPD mono-esters: what is detected? x x1 5 +ESI EIC( , , , ) Scan Frag=15.V _1-palmitoyl-3MCPD_MS.d H 2.95 Sn1-3-MCPD mono-esters +ESI EIC( , , , ) Scan Frag=15.V _1-palmitoyl-2MCPD_MS.d Sn1-2-MCPD mono-esters 2 H x1 5 +ESI EIC( , , , ) Scan Frag=15.V _2-palmitoyl-3MCPD_MS.d 1 H 2.98 Sn2-3-MCPD mono-esters Counts vs. Acquisition Time (min) MCPD mono-esters: No separation of isomers (2-,3-MCPD, Sn1 and Sn2) Different MS response (e.g. 2-palmitoyl-3-MCPD is 4% less than Sn1) 22

23 MCPD di-esters: what is detected? x x x ESI EIC( , , , ) Scan Frag=19.V 11331_1_2_distearoyl-3-MCPD.d +ESI EIC( , , , ) Scan Frag=19.V 11339_1_3_distearoyl-2-MCPD.d +ESI EIC( , , , ) Scan Frag=19.V _mix_distearoyl-2-3-MCPD.d di-stearoyl-3-mcpd di-stearoyl-2-mcpd Mix 1: Counts vs. Acquisition Time (min) MCPD di-esters: No separation of isomers (2- and 3-MCPD) Different response (e.g. Di-stearoyl-2-MCPD is 3% less) 23

24 Agenda 24

25 Sensitivity (µg/kg) Target low level and high throughput "Dilute and shoot" Sample prep. Rapid Matrix effect Sensitivity Developement phase Instrument stability Sensitivity High frequency Instrument cleaning Less maintenance Inj. 25

26 Method n 1: Gel Permeation Chromatography (GPC) for GE purification Area Weißhaar et al. Eur. J. Lipid Sci. Technol. 21, 112, Conditions: 1g oil in 1mL (yclohexane : Ethyl Acetate 1:1) 4 ml injected on SX3 BioBeads (Bio-Rad), flow at 5 ml/min Collect 9-13mL Dry under vacuum 2.E+8 Palm oil elution profile TAG GE-laurate GE-linoleate GE-linolenate GE-myristate GE-oleate GE-palmitate GE-stearate 2.E E+8 5.E+7 DAG GEs collection.e Elution Volume (ml) Additional clean up for high MAG/DAG content SPE Si cartridges (5mg) CH22 (1 ml) elution 26

27 SGS Indirect method glycidol in µg/g Glycidyl-esters: Indirect vs direct (#1) 1 palm oil samples analysed by: Nestlé (Direct Method: GPC, SPE, QqQ analysis) External laboratory (Indirect Method : alkaline hydrolysis, PBA derivatization, GC-MS analysis) Scope Equipment Indirect method All oils GC-MS Direct method All oils (except MCT oils) GPC + LC- MS/MS Chemical Standards Indirect vs direct - 1 palm oil samples Y=X y = x R² =.9946 n Linear (Indirect vs Direct) Performances (sensitivity, automation, routine) Confidence (analyte transformation) Medium Low High High Nestlé Direct method glycidol in µg/g

28 MCPD esters are not separated from TAG and DAG by GPC Area GE MCPD monoesters MCPD di-esters Method 1: GPC Method 2: C18+Si Method 3: Si 2.5E+8 2.E+8 TAG Lack of resolution: 1.5E+8 TAG MCPD-di-esters DAG MCPD-di-esters 1.E+8 5.E+7 MCPD di-esters DAG MCPD mono-esters Glycidyl esters DAG MCPD-mono-esters Material tested: SX1; SX3; SX8.E Elution Volume (ml) No extension of GPC method for MCPD-esters 28

29 Area GEs Area MCPD mono Area Method n 2 for MEs (mono-esters) and GEs Masukawa et al. J. leo Sci. 59, (2) (21) Shimizu et al. J. leo Sci. 59 (1), (21) Masukawa et al. JACS 88 (1), (211) 1st SPE: C18: 2g C18,1mg oil, 25ml ACN 8.E+6 GEs MCPD-mono DAG TAG 6.E+6 4.E+6 2.E+6.E ml (Acetonitrile) 2nd SPE: Si: 5mg, 25ml CH E+7 1.E+7 8.E+6 6.E+6 4.E+6 2.E+6.E+ GEs MCPD mono 1.E+6 1.E+6 1.E+6 8.E+5 6.E+5 4.E+5 2.E+5.E ml CH22 MCPD di-esters coelute with TAG (SPE C18) No DAG after Si-SPE 29

30 Method n 2: recoveries 2 g C mg silica gel SPE 6 palm oil sample spiked at.5 µg/g and 1µg/g. GE MCPD monoesters MCPD di-esters Method 1: GPC Method 2: C18+Si Method 3: Si 16% 14% 12% 1% 8% 6% 4% 2% % Spiking.5µg/g Spiking 1µg/g 3

31 MCPD di-esters Area Method n 3 for MEs (di-esters) Silica gel chromatography column SiH 3g, 4mg oil in hexane 65ml CH22 4% in hexane GE MCPD monoesters MCPD di-esters Method 1: GPC Method 2: C18+Si Method 3: Si 3.E+ 2.5E+ 2.E+ 1.5E+ 1.E+ 5.E-1 Method n 3 : 3g SiH, 4 mg oil collect 1-palmitoyl-2- stearoyl-3- chloropropanediol bis-palmitoyl-3- chloropropanediol di-oleate-3- chloropropanediol oleate-palmitate-3- chloropropanediol 18% 16% 14% 12% 1% 8% 6% 4% 2% % Spiking.5 µg/g Spiking 1 µg/g.e+ TAG Elution volume (ml) m SiH /m oil > 75 MCPD mono-esters : DAG interference GEs: high volume 31

32 Direct method, MCPD in µg/g (Sum MCPD mono- and di-esters) MEs: Direct vs Indirect method 32 oil samples analysed by: Direct Method: MCPD mono-esters (2x SPE) + MCPD di-esters (silica) LC-ToF Indirect Method : acidic hydrolysis, HFBI derivatization GC-MS Σ 7 MEs (mono) + Σ 1 MEs (di) direct indirect 2-MCPD + 3-MCPD Total MCPD in µg/g Direct vs Indirect method y =.9747x R² =.9639 palm oil Palm olein sunflower 3 coconut oil 2 Palm kernel oil 1 Y = X Indirect method,mcpd in µg/g (Sum 3- and 2-MCPD ) 32

33 MCPD-esters: Indirect vs direct Scope Indirect method All oils Direct method All except: Coconut Palm Kernel 1% 8% 6% 4% 2% % 29 palm oil samples 65% 9% Equipment GC-MS LC-MS/MS LC-ToF 3-MCPD (Indirect) MCPD di-esters (Direct) Chemical Standards 2 17 available Performances (sensitivity, automation, routine) Confidence (analyte transformation) Medium Medium Low 2 extractions High n1 n2 n1 n

34 Conclusion No detection issue for direct determination: LC-HRMS or MS/MS fit for purpose Sample preparation highly required for better sensitivity and robustness Method Convenience (Quick, easy, cheap, robust) Direct GEs Indirect 2- and 3-MCPD Recommendation Direct Silica Column Direct 2x SPE (C18 + SiH) GEs MCPD mono-esters MCPD di-esters Compound class

35 Aknowledgements