Xinyu LIU, Peter JOZA, Andrew MASTERS, Bill RICKERT

Transcription

1 Determination of Ethylene Oxide (ETO) in Mainstream Cigarette Smoke Using Hydrobromic Acid Derivatization and Gas Chromatography-Mass Spectrometry Method Xinyu LIU, Peter JOZA, Andrew MASTERS, Bill RICKERT 2014 CORESTA CONGRESS October 12-16, 2014 Québec City, Canada LABSTAT INTERNATIONAL ULC. 262 Manitou Drive Kitchener, Ontario, Canada N2C 1L3 Phone: (519) Fax: (519) Web: 1

2 Objectives To develop a reliable method for the analysis of ethylene oxide in tobacco smoke To analyze low concentrations of ethylene oxide in new generation products (e.g. e- cigarette aerosols and heat-not-burn emissions) 2

3 Methods for the Direct Analysis of ETO Authors & Journal Sample matrix Method Gordon et al. 57 th TSRC (2003) Mainstream cigarette smoke GC-MS Dong et al. 62 th TSRC (2008) Masters et al. Coresta (2009) Gillman et al. Coresta 2012 Otte et al. Coresta 2013 Mainstream cigarette smoke Mainstream cigarette smoke Mainstream cigarette smoke Mainstream cigarette smoke GC-MS GC-MS GC-MS GC-MS 3

4 Physicochemical Properties Appearance: colorless gas Molecular formula: C 2 H 4 O (MW=44.05) BP: 10.8 C MP: -111 C 4

5 Relative Abundance (%) EI Mass Spectrum Mass library: Wiley, NIST/EPA/NIH, FFNSC 5

6 Potential Interference Peaks 6

7 Direct Method : Analytical Conditions Instrument Column Parameters DB-5ms (60 mx0.25 mmx1.0 µm) Injector temperature 220 C Oven temperature Column flow 35 C for 6.5 minutes; 20 C per minute to 210 C; hold 3 minutes. 1.5 ml/min Injection mode Split mode with a split ratio 20:1 Injection volume 1 µl Transfer line temperature 200 C Source temperature 230 C MS quad 150 C Ionization mode Scan 7

8 Direct Method: Chromatogram (3R4F Smoke ) Methanethiol Match 808, R. Match 962, Prob. 92.7% m/z=47 Ethylene oxide RT time window m/z=44 TIC min 8

9 Direct Method: Analytical Conditions Instrument Parameters Column: DB-624 ms (60 mx0.25 mmx1.4 µm) Injector temperature 220 C Column temperature 35 C for 10 minutes; 20 C per minute to 250 C; hold 3 minutes. Column flow 1.5 ml/min Injection method Split mode with split ratio 20:1 Injection volume 1 µl Transfer line temperature 200 C Source temperature 230 C MS quad 150 C Ionization mode Scan 9

10 Direct Method: Chromatogram (3R4F Smoke ) m/z=44 44 Ethylene oxide? TIC MeOH min 10

11 Effects of Interference Peak on ETO Analysis 11

12 Reaction Sequence: Indirect Method C 2 H 4 O (Ethylene Oxide) + HBr (Hydrobromic Acid) BrC 2 H 4 OH (2-Bromoethanol) Eliminate the interference from common trapping solvent (e.g. methanol) Provide more specific ion m/z=124 for reliable quantitation analysis 12

13 Experimental Steps Add 1.0 g anhydrous Na 2 SO 4 Accurately transfer 2 ml sample Add 200 µl 48% HBr, wait 5 min Add 0.3 g Na 2 CO 3, wait for 30 min Spike 200 µl ISTD (D 4-2-bromoethanol ) Centrifuge 5min at 2500 rpm Transfer supernatant in vial GC/MS analysis 13

14 Analytical Conditions Instrument Parameters Column ZB-1 (60 mx0.25 mmx1.0 µm) Injector temperature 250 C Oven temperature 100 C for 10 minutes; 20 C per minute to 250 C; hold 3 minutes Column flow 1mL/min Injection method Split mode with split ratio 10:1 Injection volume 1 µl Transfer line temperature 250 C Source temperature 230 C MS quad 150 C Ionization mode SIM 14

15 MS Quantization Parameters Component RT Quantifier ion 2-bromoethanol (ETO-HBr) D 4-2-bromoethanol (ISTD) Dwell time Qualifier ion (min) (m/z) (ms) (m/z) / NA 15

16 Response Optimization of Derivatization Time (3R4F smoke) Derivatization time (min) 16

17 Response Optimization Amount of Derivatization Reagent (3R4F Smoke) Volume (µl) of 48% aqueous HBr 17

18 Std level Linear Concentration Range 2-Bromoethanol (µg/ml) Y=0.392x R 2 =

19 Recovery (Accuracy) Method Characteristics Laboratory Reagent Blank (LRB) (ng/cig) 0.00 Laboratory Fortified Blank (LFB) (%) Laboratory Fortified Matrix (LFM) (%) Detection Limit Limit of Detection (LOD) (ng/cig) 33.7 Limit of Quantification (LOQ) (ng/cig)

20 Mainstream Smoke Analysis (3R4F) ETO-HBR m/z=124 ISTD m/z= Min 20

21 E-cigarette Aerosol Analysis ETO-HBR m/z=124 ISTD m/z= Min

22 Method Comparison (Derivatization vs Direct analysis) Method Sample Sample Replicates Mean Std. Dev. RSD ID Matrix [n] [µg/cig] [µg/cig] [%] Direct analysis* 3R4F MS ISO HBr-derivatization 3R4F MS Intense R4F MS ISO R4F MS Intense E-cig** MS Intense *DB-5 column, full scan mode, ion-trap detector was used. ** Example for demonstration. 22

23 Summary The Hydrobromic acid-derivatization method can be used to effectively solve sample matrix interference The developed method can be applied to analyze ethylene oxide in cigarette smoke and in new generation products ( e.g. e-cigarette aerosols and heat-not-burn emissions) 23

24 Acknowledgements Labstat International ULC Sample Preparation Technician and Analytical Team (Mr. MingZhong Cui, Mrs. Helena Coetzer, Mrs. Gabriela Pop, Mr. Ali Ahmed) 24