Quantitative Analysis of Methyl Parathion Pesticides in a Polydimethylsiloxane Microfluidic Channel Using Confocal Surface-Enhanced Raman Spectroscopy

A fast and ultra-sensitive trace analysis of methyl parathion pesticides in a polydimethylsiloxane (PDMS) microfluidic channel was investigated using confocal surface-enhanced Raman spectroscopy (SERS). A three-dimensional PDMS-based passive micromixer was fabricated for this purpose. This PDMS micromixer showed a high mixing efficiency because a strong chaotic advection was developed by the simultaneous vertical and transverse dispersion of the confluent streams. The confocal SERS signal was measured after methyl parathion pesticides were effectively adsorbed onto silver nanoparticles while flowing along the upper and lower alligator-teeth-shaped PDMS channel. A quantitative analysis of the methyl parathion pesticides was performed based on the measured peak height at 1246 cm−1. Our method has a detection limit of 0.1 ppm. This value satisfies the requirement recommended by the Collaborative International Pesticides Analytical Council (CIPAC) for the determination of methyl parathion in pesticide formulations. This study demonstrates the feasibility of using confocal SERS for the highly sensitive detection of methyl parathion pesticides in a PDMS microfluidic channel.

[1]  D. Meisel,et al.  Adsorption and surface-enhanced Raman of dyes on silver and gold sols , 1982 .

[2]  E. Papadopoulou-mourkidou,et al.  Development of a semi-automated high-performance liquid chromatographic-diode array detection system for screening pesticides at trace levels in aquatic systems of the Axios River basin , 1996 .

[3]  S. Skoulika,et al.  Univariate and Multivariate Calibration for the Quantitative Determination of Methyl-Parathion in Pesticide Formulations by FT-Raman Spectroscopy , 2000 .

[4]  G. Naidu,et al.  Photometric determination of malathion with molybdenum. , 1990, Talanta.

[5]  A. Garrido-Frenich,et al.  Analysis of Pesticides in Water Samples Using GC-ECD and GC-MS/MS Techniques , 1999 .

[6]  A. L. Hart,et al.  The response of screen-printed enzyme electrodes containing cholinesterases to organo-phosphates in solution and from commercial formulations , 1997 .

[7]  Duncan Graham,et al.  Surface‐Enhanced Resonance Raman Scattering as a Novel Method of DNA Discrimination , 2000 .

[8]  C. Gonçalves,et al.  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. , 2004, Journal of chromatography. A.

[9]  Shiv k. Sharma,et al.  Optimization of a Flow Injection Sampling System for Quantitative Analysis of Dilute Aqueous Solutions Using Combined Resonance and Surface-Enhanced Raman Spectroscopy (SERRS) , 1990 .

[10]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[11]  R. Dasari,et al.  Ultrasensitive chemical analysis by Raman spectroscopy. , 1999, Chemical reviews.

[12]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[13]  J. Laserna.  Combining fingerprinting capability with trace analytical detection: surface-enhanced raman spectrometry , 1993 .

[14]  Eun Kyu Lee,et al.  Ultra-sensitive trace analysis of cyanide water pollutant in a PDMS microfluidic channel using surface-enhanced Raman spectroscopy. , 2005, The Analyst.

[15]  E. Papadopoulou-mourkidou,et al.  Rapid method for the analysis of a variety of chemical classes of pesticides in surface and ground waters by off-line solid-phase extraction and gas chromatography-ion trap mass spectrometry , 1996 .

[16]  R. V. Van Duyne,et al.  A glucose biosensor based on surface-enhanced Raman scattering: improved partition layer, temporal stability, reversibility, and resistance to serum protein interference. , 2004, Analytical chemistry.

[17]  D J Kim,et al.  An easily integrative and efficient micromixer and its application to the spectroscopic detection of glucose-catalyst reactions. , 2005, The Analyst.

[18]  Eun Kyu Lee,et al.  Highly sensitive signal detection of duplex dye-labelled DNA oligonucleotides in a PDMS microfluidic chip: confocal surface-enhanced Raman spectroscopic study. , 2005, Lab on a chip.

[19]  Claudio Frausto-Reyes,et al.  Quantitative NIR-Raman analysis of methyl-parathion pesticide microdroplets on aluminum substrates. , 2004, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[20]  Steven R. Emory,et al.  Probing Single Molecules and Single Nanoparticles by Surface-Enhanced Raman Scattering , 1997, Science.

[21]  Eun Kyu Lee,et al.  Analysis of Passive Mixing Behavior in a Poly(Dimethylsiloxane) Microfluidic Channel Using Confocal Fluorescence and Raman Microscopy , 2004, Applied spectroscopy.

[22]  T. Vo‐Dinh,et al.  Surface-enhanced Raman spectrometry of organophosphorus chemical agents. , 1987, Analytical chemistry.

[23]  A. Becke.  Density-functional thermochemistry. III. The role of exact exchange , 1993 .