Direct sampling tandem mass spectrometry (MS/MS) and multiway calibration for isomer quantitation.
Direct sampling tandem mass spectrometry (MS/MS) was used for the quantitation of mixtures of the isomers 2-, 3- and 4-ethyl pyridine. The similarity between the analytes and the second-order nature of MS/MS data require the use of multivariate calibration techniques capable of handling multiway data. Multilinear PLS (N-PLS) was applied here, as well as the alternative technique of unfolding the data and using standard two-way PLS. Particular attention was paid to the optimal type of spectral preprocessing. Due to the presence of heteroscedastic noise the logarithmic transform of the spectra prior to calibration gives the best results. Predictions errors of the order of 10-15% were obtained, which compare well with other results found in the literature.
Instituto de Química, Universidade Estadual de Campinas-UNICAMP, CP 6154, 13083-970 Campinas, São Paulo, Brazil.
Cleidiane G
CG
Zampronio
Stephen P
SP
Gurden
Luis Alberto B
LA
Moraes
Marcos N
MN
Eberlin
Age K
AK
Smilde
Ronei J
RJ
Poppi
D002138:Calibration; D004785:Environmental Pollutants / Q000032:analysis*; D007536:Isomerism; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D011725:Pyridines / Q000032:analysis*
D004785:Environmental Pollutants; D011725:Pyridines; C051672:2-ethylpyridine