TY - JOUR
T1 - Determination of chlorpyrifos and its metabolites in rat brain tissue using coupled-column liquid chromatography/electrospray ionization tandem mass spectrometry
AU - Williamson, Leah N.
AU - Terry, Alvin V.
AU - Bartlett, Michael G.
PY - 2006
Y1 - 2006
N2 - A method has been developed to quantify chlorpyrifos (O,O-diethyl-O-[3,5,6, -trichloro-2-pyridyl] phosphorothionate) and its metabolites chlorpyrifos-oxon (O,O-diethyl-O-[3,5,6,trichloro-2-pyridinyl] phosphate) and TCP (3,5,6,-trichloro-2-pyridinol) in rat brain tissue by coupled-column liquid chromatography/electrospray ionization tandem mass spectrometry (LC/LC/ESI-MS/MS). Rat brains were homogenized and treated by protein precipitation using ice-cold acetonitrile. The supernatant was directly injected onto the coupled-column system. Sample clean-up was achieved on a Zorbax Extend-C18 column (2.1 X 50 mm, 5 μm) using a mobile phase of acetonitrile/water with 0.0025% formic acid (40:60, v/v). The compounds were separated isocratically on a Zorbax Eclipse XDB C8 column (2.0 X 150 mm, 5 μm) using a mobile phase of acetonitrile/water with 0.0025% formic acid (75:25, v/v). Chlorpyrifos and chlorpyrifos-oxon were detected in positive ion mode using multiple reaction monitoring (MRM). TCP was detected in negative ion mode using precursor-to-precursor transition monitoring. The method was validated and the specificity, linearity, limit of quantitation (LOQ), precision, accuracy, stability, and recoveries were determined. Calibration curves for all three analytes yielded correlation coefficients of 0.993 or greater. The LOQs were 25.3 ng/g for chlorpyrifos and 6.3 ng/g for chlorpyrifos-oxon and TCP. All precision relative standard deviations (RSDs) were less than 16% for the LOQ and less than 11% for the other QC samples. This method was successfully applied to six rats that were injected subcutaneously with chlorpyrifos.
AB - A method has been developed to quantify chlorpyrifos (O,O-diethyl-O-[3,5,6, -trichloro-2-pyridyl] phosphorothionate) and its metabolites chlorpyrifos-oxon (O,O-diethyl-O-[3,5,6,trichloro-2-pyridinyl] phosphate) and TCP (3,5,6,-trichloro-2-pyridinol) in rat brain tissue by coupled-column liquid chromatography/electrospray ionization tandem mass spectrometry (LC/LC/ESI-MS/MS). Rat brains were homogenized and treated by protein precipitation using ice-cold acetonitrile. The supernatant was directly injected onto the coupled-column system. Sample clean-up was achieved on a Zorbax Extend-C18 column (2.1 X 50 mm, 5 μm) using a mobile phase of acetonitrile/water with 0.0025% formic acid (40:60, v/v). The compounds were separated isocratically on a Zorbax Eclipse XDB C8 column (2.0 X 150 mm, 5 μm) using a mobile phase of acetonitrile/water with 0.0025% formic acid (75:25, v/v). Chlorpyrifos and chlorpyrifos-oxon were detected in positive ion mode using multiple reaction monitoring (MRM). TCP was detected in negative ion mode using precursor-to-precursor transition monitoring. The method was validated and the specificity, linearity, limit of quantitation (LOQ), precision, accuracy, stability, and recoveries were determined. Calibration curves for all three analytes yielded correlation coefficients of 0.993 or greater. The LOQs were 25.3 ng/g for chlorpyrifos and 6.3 ng/g for chlorpyrifos-oxon and TCP. All precision relative standard deviations (RSDs) were less than 16% for the LOQ and less than 11% for the other QC samples. This method was successfully applied to six rats that were injected subcutaneously with chlorpyrifos.
UR - http://www.scopus.com/inward/record.url?scp=33749327948&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33749327948&partnerID=8YFLogxK
U2 - 10.1002/rcm.2647
DO - 10.1002/rcm.2647
M3 - Article
C2 - 16912982
AN - SCOPUS:33749327948
SN - 0951-4198
VL - 20
SP - 2689
EP - 2695
JO - Rapid Communications in Mass Spectrometry
JF - Rapid Communications in Mass Spectrometry
IS - 18
ER -