ตัวอย่าง Abstract
Selection of surfactant-modified sorbents for on-line solid phase
extraction of carbamate pesticides
Prapha Arnnok*, Rodjana Burakham
Materials Chemistry Research Center, Department of Chemistry and Center for Innovation in Chemistry, Faculty of Science,
Khon Kaen University, Khon Kaen 40002, Thailand.(e-mail: praphaar@gmail.com)
Various surfactant-modified sorbents, including sodium dodecyl sulfate (SDS)-coated alumina,
cetyltrimethyl ammonium bromide (CTAB)-coated silica, CTAB-coated zeolite and CTAB-coated
zeolite NaY, have been created using different surfactant concentrations. The performance of these
modified sorbents forsorption of carbamate pesticides was comparative studied. The studied
carbamatepesticides includesoxamyl, methomyl, aldicarb, carbofuran, carbaryl, isoprocarb,
methiocarb, promecarb and carbosulfan. Analysis was performed by HPLC using a LichroCART RP18 column with gradient elution of methanol and 0.1% acetic acid, at a flow rate of 1.0 mL min-1. An
on-line solid phase extraction (SPE) equipped with HPLC system was developed. CTAB-modified
zeolite NaY, which giving the highest performance for carbamate pesticide sorption, was selected as
solid sorbent. The optimum conditions for on-line SPE including loading flow rate, loading volume,
elution solvent and elution time, were investigated. Six carbamate pesticides (carbofuran, carbaryl,
isoprocarb, methiocarb, promecarb and carbosulfan) were concentrated when 20 mL of 1 mg L-1
pesticides solution was loaded at a flow rate of 1 mL min-1. After loading, the sorbed pesticides were
eluted using methanol at a flow rate of 0.5 mL min-1 for 1.5 min and analyzed by HPLC. Among
concentrated pesticides, five carbamate pesticides excepted carbosulfan were successfully quantitative
determined with enrichment factors in the range of 5 – 551. This manner required the low volume of
organic solvent for complete elution of analytes (typically 0.75 mL) avoided the need of using timeconsuming and organic waste. Furthermore, the study on regenerability of modified sorbent by
on-line system indicated that zeolite NaYcould be re-coated with CTAB for 7 times. The proposed
on-line SPE approach was mostly suitable for carbamate pesticide concentration with high enrichment
factor, organic solvent reduced, regenerability and cost effectiveness.
Keywords: surfactant-modified sorbent, carbamate pesticide, sorption, retention, on-line SPE, liquid
chromatography
Selected References:
1.
2.
Karapamagioto, H.K.; Sabatini, D.A.; Bowman, R.S. Water Res., 2005, 39, 699–709.
Vichapong, J.; Burakham, R.; Srijaranai, S.; Grudpan, K. J. Sep. Sci., 2011, 34, 1574–1581.
Prapha Arnnok, Ph.D. Student
Khon Kaen University, Thailand, Chemistry, B.Sc. 2006
Khon Kaen University, Thailand, Analytical Chemistry, M.Sc. 2008
Research field: Liquid Chromatography, Sample Preparation, Pesticide analysis