title: Benchmarking of candidate detectors for multiresidue analysis of pesticides by comprehensive two-dimensional gas chromatography.
abstract: The present study discusses the relevance, performance and complementarities of flame photometric detector in phosphorus (FPD/P) and sulfur (FPD/S) modes, micro electron capture detector (μECD), nitrogen phosphorus detector (NPD), flame ionization detector (FID) and time-of-flight mass spectrometer (TOF/MS) for the comprehensive two-dimensional gas chromatography (GC×GC) analysis of pesticides. A mix of 41 pesticides including organophosphorus pesticides, synthetic pyrethroids and fungicides was investigated in order to benchmark GC×GC systems in terms of linearity (R(2)), limits of detection (LOD), and peak shape measures (widths and asymmetries). A mixture of pesticides which contained the heteroatoms phosphorus, sulfur, nitrogen and one or several halogens, was used to acquire a comparative data set to monitor relative detector performances. GC×GC datasets were systematically compared to their GC counterpart acquired with an optimized one-dimensional GC configuration. Compared with FID, considered the most appropriate detector in terms of suitability for GC×GC, the element-selective detector FPD/P and μECD best met the peak widths (0.13-0.27s for FPD/P; 0.22-0.26s for μECD) and tailing factors (0.99-1.66 for FPD/P; 1.32-1.52 for μECD); NPD exhibited similar peak widths (0.23-0.30s), but exceeded those of the above detectors for tailing factors (1.97-2.13). These three detectors had improved detection limits of 3-7 times and 4-20 times lower LODs in GC×GC mode compared with FID and TOF-MS, respectively. In contrast FPD/S had poor peak shape (tailing factor 3.36-5.12) and much lower sensitivity (10-20 fold lower compared to FPD/P). In general, element-selective detectors with favorable detection metrics can be considered viable alternatives for pesticide determination using GC×GC in complex matrices. The controversial issue of sensitivity enhancement in GC×GC was considered for optimized GC and GC×GC operation. For all detectors, we found no significant LOD enhancement in GC×GC.
authors.affiliation: INRA, UR370 QuaPA, Micro-contaminants, Aroma and Separation Science Group, 63122 Saint-Genès-Champanelle, France; Centre for Green Chemistry School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia. Electronic address: erwan.engel@clermont.inra.fr.
authors.forename: Erwan
authors.initials: E
authors.lastname: Engel
authors.forename: Jérémy
authors.initials: J
authors.lastname: Ratel
authors.forename: Patrick
authors.initials: P
authors.lastname: Blinet
authors.forename: Sung-Tong
authors.initials: ST
authors.lastname: Chin
authors.forename: Gavin
authors.initials: G
authors.lastname: Rose
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Marriott
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D005410:Flame Ionization / Q000379:methods; D057230:Limit of Detection; D009943:Organophosphorus Compounds / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides
keywords: FPD/P and FPD/S; GC×GC; NPD; Pesticides; TOF/MS; μECD