The Malaysian Journal of Analytical Sciences Vol 12 No 1 (2008): 1 – 9

 

 

 

APPLICATION OF SOLID-PHASE MICROEXTRACTION FOR THE DETERMINATION OF PESTICIDES IN VEGETABLE SAMPLES BY GAS CHROMATOGRAPHY WITH AN ELECTRON CAPTURE DETECTOR

 

Chai Mee Kin¹, Tan Guan Huat²  and Asha Kumari²

 

¹Dept. of Science and Mathematics, College of Engineering,Universiti Tenaga Nasional,

Km 7, Jalan Kajang-Puchong,43009 Kajang, Selangor

²Dept. of Chemistry, Faculty of Science, Universiti Malaya, Lembah Pantai,

50603 Kuala Lumpur

 

Abstract

A solid-phase microextraction (SPME) method has been developed for the determination of 9 pesticides in 2 vegetables -cucumber and tomato - samples, based on direct immersion mode and subsequent desorption into the injection port of a gas chromatograph with an electron capture detector (GC-ECD). The main factors affecting the SPME process such as extraction time and temperature, desorption time and temperature, the effect of salt addition and fiber depth into the liner were studied and optimized. The analytical procedure proposed consisted of a 30-minute ultrasonic extraction of the target compounds from 1.0 g vegetable samples with 5 mL of distilled water. Then, the samples were filtered and topped up with distilled water to 10 mL. The analytes in this aqueous extract were extracted for 15 minutes with a 100 µm thickness polydimethylsiloxane SPME  fiber. Relative standard deviations for triplicate analyses of samples were less than 10%. The  recoveries of the pesticides studied in cucumber and tomato ranged from 52% to 82% and the RSD were below 10%. Therefore, the proposed method is applicable in the analysis of pesticides in vegetable matrices. SPME has been shown to be a simple extraction technique,  which  has  a  number  of  advantages  such  as  solvent  free  extraction,  simplicity  and  compatibility  with  the chromatographic analytical system.

 

Keywords: Solid-Phase Microextraction, GC-ECD, pesticides, vegetables

 

References

1.     Beltran  J,  Peruga  A,  Pitarch  E,  Lopez,  FJ  and  Hernandex  F  (2003),  “  Application  of  solid-phase microextraction  for  the  determination  of  pyrethroid  residues  in  vegetable  samples  by  GC-MS”,  Anal. Bional. Chem. 376, 502-511.

2.     Betran J, Lopez F.J, Hernandez F (2000), “Solid-phase microextraction in pesticide residue analysis.”, J. of Chromatography A, 885, 389-404.

3.     Goncalves C, Alpendurade MF (2004), “Solid-phase micro-extraction-gas chromatography – (tandem) mass spectrometry as a tool for pesticide residue analysis in water samples at high sensitivity and selectivity with confirmation capabilities.” J. of Chromatography A, 1026, 239-250.

4.     Blanco MC, Rodriguez BR, Grande BC, Gandara JS (2002), “Optimization of solid-phase extraction and solid-phase microextraction for the determination of α- and β- endosulfan in water by gas chromatography- electron capture detection.” J. of Chromatography A, 976, 293-299.

5.     Tomkins BA, Barnard AR (2002), “Determination of organochlorine pesticides in ground water using solid- phase microextraction followed by dual-column gas chromatography with electron-capture detection.” J. of Chromatography A, 964, 21-33.

6.     Hernandez F, Pitarch E, Beltran J, Lopez FJ (2000), “Headspace solid-phase microextraction in combination with  gas  chromatography and  tandem mass  spectrometry for  the determination  of organochlorine  and organophosphorus pesticides in whole human blood.”, J.of Chromatography B, 769, 65-77.

7.     Lopez FJ, Pitarch E, Egea S, Beltran J, Hernandez F (2001), “Gas chromatographic determination of organochlorine and organophosphorus pesticides in human fluids using solid phase microextraction.”, Anal. Chimica Acta, 433, 217-226.

8.     Snow NH (2000), “Solid-phase microextraction of drugs from biological matrices.”, J. of Chromatography A, 885, 445-455.

9.     Kumazawa T, Suzuki O (2000), “Separation methods for amino group-possessing pesticides in biological samples.” J. of Chromatography B, 747, 241-254.

10. Theodoris G, Koster EHM, Jong GJ (2000), “Solid-phase microextraction for the analysis of biological samples.” J. of Chromatography B, 745, 49-82.

11. Navalon A, Prieto A, Araujo L, Vilchez JL (2002), “Determination of oxadiazon residues by headspace solid-phase microextraction and gas chromatography-mass spectrometry.” J. of Chromatography A, 946, 239-245.

12. Hernandez  F,  Beltran  J,  Lopez  FJ,  Gaspar  JV  (2000),  “Use  of  solid-phase  microextraction  for  the quantitative determination of herbicides in soil and water samples.” Anal. Chem. 72, 2313-2322.

13. Zambonin CG, Palmisano F (2000), “Determination of triazines in soil leachates by solid-phase microextraction coupled to gas chromatography-mass spectrometry.” J. of Chromatography A, 874, 247-255

14. Baciocchi R, Attina M, Lombardi G, boni MK (2001), “Fast determination of phenols in contaminated soils.” J. of Chromatography A, 911, 135-141.

15.  Bouaid A, Ramos L, Gonzalez MJ, Fernandez P, Camara C (2001), “Solid-phase microextraction method for  the  determination  of  atrazine  and  four  organophosphorus  pesticides  in  soil  samples  by  gas chromatography.” J. of Chromatography A, 939, 13-21.

16. Eisert R, Jackson S, Krotzky A (2001), “Application of on-site solid-phase microextraction in aquatic dissipation studies of profoxydim in rice.” J. of Chromatography A, 909, 29-36.

17. Fidalgo N, Centineo G, Blanco E (2003), “Solid-phase microcextraction as a clean-up and preconcentration procedure for organochlorine pesticides determination in fish tissue by gas chromatography with electron capture detection.” J. of Chromatography A, 1017, 35-44.

18.  Simplicio AL, Boas LV (1999), “ Validation of a solid-phase microextraction method for the determination of organophosphorus pesticides in fruits and fruit juice.” J. of Chromatography A, 833, 35-42.

19. Lamprodon DA, Albanis TA (2002), “Headspace solid-phase microextraction applied to the analysis of organophosphorus insecticides in strawberry and cherry juices.” J. of Agricultural and Food Chemistry, 50, 3359-3365.

20.  Matich  AJ,  Rowan  DD,  Banks  NH  (1996),  “Solid-phase  microextraction  for  quantitative  headspace sampling of apple volatiles.” Anal. Chem. 68, 4114-4118.

21.  Holt Ru (2001), “Mechanisms Effecting analysis of volatile flavour components by solid-phase microextraction and gas chromatography.” J. of Chromatography A, 937, 107-114.

22. Mestres  M,  Busto  O,  Guasch  J  (1998),  “Headspace  solid-phase  microextraction  analysis  of  volative sulphides and disulphides in wine aroma.” J. of Chromatography A, 808, 211-218.

23.  Song J, Gardner BD, Holland JF, Beaudry RM (1997), “Rapid analysis of volatile flavour compounds in apple fruit using SPME and GC/Time-of-Flight Mass Spectrometry.” J. of Agricultural and Food Chemistry, 45, 1801-1807.

24. Song  J,  Fan  L,  Beaudry  RM  (1998),  “Application  of  solid-phase  microextraction  and  Gas Chromatography/Time-of-Flight Mass Spectrometry for rapid analysis of Flavour volatiles in tomato and strawberry fruits.” J. of Agricultural and Food Chemistry, 46, 3721-3726.

25. Beltan J, Peruga A, Pitarch E, Lopez FJ (2003), “ Application of solid-phase microextraction for the determination of pyrethroid residues in vegetable samples by GC-MS.” Anal. Bioanal. Chem. 376, 502-511.

26.  Fernandez M, Padron C, Marconi L, Ghini S, Colombo R, Sabatini AG, Girotti S (2001), “Determination of organophosphorus pesticides in honeybees after solid-phase microextraction.”, J. of Chromatography A, 922, 257-265.

27.  Sen NP, Seaman SW, Page BD (1997), “Rapid semi-quantitative estimation of N-nitrosodibutylamine and N-nitrosodibenzylamine in smoked hams by solid-phase microextraction followed by gas chromatography thermal energy analysis.” J. of Chromatography A, 788, 131-140.

28.  Otero RR, Ruiz CY, Grande BC, Gandara JS (2002), “Solid-phase microextraction-gas chromatographic- mass spectrometric method for the determination of the fungicides cyprodinil and fludioxonil in white wines.” J. of Chromatography A, 942, 41-52.

29.  Zambonin CG, Cilenti A, Palmisano F (2002), “ Solid-phase microextraction and gas chromatography-mass spectrometry for the rapid screening of triazole residues in wine and strawberries.” J. of Chromatography A, 967, 255-260.

30.  Michelle LR, Jennifer SB (2001), “ Analysis of fine ant pesticides in water by solid-phase microextraction and gas chromatography/mass spectrometry of high-performance liquid chromatography/mass spectrometry.” Analytical Chimica Acta, 436, 11-20.