Low Level Determination of Triazine Herbicides using LC/MS with a New Field Free APCI Source Avinash Dalmia; Thomas White; Daniel Pentek PerkinElmer Inc., Shelton, CT 1 • • • • Objectives Develop a reverse phase HPLC method to detect triazine herbicides (propazine, atrazine, terbutylazine, simazine and irgarol) using a single quadrupole MS detector with field free APCI source Determine the detection limits for 5 triazine herbicides Study the effect of a nitrogen supply hydrocarbon trap on sensitivity determination of 5 triazine herbicides Study the fragmentation pattern of triazine herbicides compounds using APCI and capillary exit collision induced decomposition (CID) in positive ionization mode 2 SIM of 10 pg Injected on column of 5 Triazine Herbicides Method Total Ion Chromatogram (TIC) 10 pg Simazine (+) SIM at 202.2 u Cap. Exit= 90 V Atrazine Injection amt.: 1ng on column Scan range: m/z 120-300 Scan speed: 1000 u/s Triazine Herbicides Detection Limits Compound 3pg (S/N) LOD (pg) LOQ (pg) Atrazine 63 0.14 0.48 Simazine 11 0.82 2.73 Propazine 31 0.29 0.97 Ter-butylazine 18 0.50 1.67 Irgarol 29 0.31 1.03 10 pg Atrazine (+) SIM at 216.2 u Cap. Exit= 90 V Propazine Irgarol Ter-butylazine 10 pg Propazine & Ter-butylazine (+) SIM at 230.2 u Cap. Exit= 90 V Propazine Ter-butylazine Simazine 10 pg Irgarol (+) SIM at 254.2 u Cap. Exit= 90 V FlexarTM HPLC: PerkinElmer FX-10 MS: PerkinElmer FlexarTM SQ 300 MS with PerkinElmer field free APCI source Column: PerkinElmer Brownlee Supra C18, 3 µm, 2.1 x 100 mm Gradient: 60 % MeOH to 85 % MeOH in water, 5 mM ammonium formate in 7 min at 0.5 mL/min APCI source temperature: 300 oC Corona Current: 5 µA 3 4 Results & Discussion Mass Spectra of Triazine Herbicides [M+H]+ Simazine Background spectra with and without a hydrocarbon trap. Isobaric Compounds (Propazine and Ter-butylazine) Differentiated by CID [M+H-C2H4]+ Background Spectra with Hydrocarbon Filter The LOD of all 5 triazine herbicides was lower than 1 pg Ter-butylazine fragment (+) SIM at 174.2 u Cap. Exit= 150 V Atrazine 5 [M+H]+ Propazine fragment (+) SIM at 188.2 u Cap. Exit= 150 V Summary • A seven minute HPLC-MS method was developed for measurement of 5 triazine herbicides [M+H-C3H6]+ Background Spectra with No Hydrocarbon Filter [M+H]+ Propazine Field Free APCI Source Performance: 4 Orders of Magnitude Linear Dynamic Range [M+H-C3H6-C3H6]+ [M+H-C3H6]+ Atrazine Simazine [M+H]+ 216.1 u 202.1 u 4 11 63 230.1 u 30 31 Ter-butylazine 230.1 u 18 18 254.1 u 32 Ter-butylazine [M+H-C4H8 ]+ [M+H]+ 11 Propazine Irgarol 8 Log (Response ) (counts) Compound 9 3pg (S/N) with no 3pg (S/N) with hydrocarbon trap hydrocarbon trap [M+H-C4H8-C2H4]+ • With a hydrocarbon trap, the detection limit for atrazine was improved by a factor of 15; the detection limits for the other 4 triazine herbicides was unaffected 7 6 5 4 3 • The field free APCI source response was linear over 4 orders of magnitude 2 29 Irgarol Using a hydrocarbon trap for the nitrogen gas, supply, the detection limits for atrazine improved by a factor of 15 due to removal of impurity at m/z 214.1 which could be due to presence of n-butyl benzene sulfonamide. The sensitivity for the other triazine herbicides did not improve due to hydrocarbon filtering of the nitrogen supply. y = 0.99x + 4.1744 R² = 0.9996 [M+H-C4H8]+ [M+H]+ • The isobaric compounds (propazine and ter-butylazine) were differentiated further by measuring their different fragments using in-source CID 1 0 0 0.5 1 1.5 2 2.5 Log ( Atrazine) (pg) 3 3.5 4 4.5 • Using an optimized LC-MS method, the detection limits of five triazine herbicide compounds ranged from 0.14 to 0.82 pg injected on column PerkinElmer, Inc., 940 Winter Street, Waltham, MA USA (800) 762-4000 or (+1) 203 925-4602 www.perkinelmer.com