High frequency monitoring of pesticides in runoff water to improve understanding of their transport and environmental impacts.

Rainfall-induced peaks in pesticide concentrations can occur rapidly. Low frequency sampling may therefore largely underestimate maximum pesticide concentrations and fluxes. Detailed storm-based sampling of pesticide concentrations in runoff water to better predict pesticide sources, transport pathways and toxicity within the headwater catchments is lacking.

Multiresidue determination of 256 pesticides in lavandin essential oil by LC/ESI/sSRM: advantages and drawbacks of a sampling method involving evaporation under nitrogen.

The determination of 256 multiclass pesticides in lavandin essential oil has been performed by liquid chromatography-electrospray ionization tandem mass spectrometry using the scheduled selected reaction monitoring mode available on a quadrupole-linear ion trap mass spectrometer. With the aim of improving the limits of quantification (LOQs) of the target molecules, a sampling step based on evaporation of the essential oil under a nitrogen flow assisted by controlled heating was tested. The LOQs determined in this case were compared with the values obtained with the classic dilution preparation method.

Changes in concentrations of fluoroquinolones and of ciprofloxacin-resistant Enterobacteriaceae in chicken feces and manure stored in a heap.

This study evaluated the impact of storing chicken manure on the degradation of enrofloxacin (ENR) and ciprofloxacin (CIP), and on the survival of CIP-resistant Enterobacteriaceae. At 24 d of age, half of 8900 chickens received ENR for 5 d. After the animals departed, their manure was stored in two heaps for 63 d.

Multiresidue analysis of multiclass pesticides in lavandin essential oil by LC/MS/MS using the scheduled selected reaction monitoring mode.

In this paper we describe the development of the first multiclass pesticide residue method applied to essential oils. A total of 70 pesticides covering a wide range of polarity and currently used on essential oil crops have been included in the method. The procedure consists of a 10-fold dilution of lavandin essential oil followed by a direct injection analysis by liquid chromatography/tandem mass spectrometry.

Effect of thiamethoxam on cockroach locomotor activity is associated with its metabolite clothianidin.

Background: In the present study, the effect of thiamethoxam and clothianidin on the locomotor activity of American cockroach, Periplaneta americana (L.), was evaluated. Because it has been proposed that thiamethoxam is metabolised to clothianidin, high-performance liquid chromatography coupled with mass spectrometry was used to evaluate the amount of clothianidin on thiamethoxam-treated cockroaches.

Advantages of the scheduled selected reaction monitoring algorithm in liquid chromatography/electrospray ionization tandem mass spectrometry multi-residue analysis of 242 pesticides: a comparative approach with classical selected reaction monitoring mode.

This paper illustrates the advantages of using the scheduled selected reaction monitoring (sSRM) algorithm available in Analyst Software 1.5 to build SRM acquisition methods in the application field of pesticide multi-residue analysis. The principle is to monitor the SRM transitions only when necessary.

Influence of complexation phenomena with multivalent cations on the analysis of glyphosate and aminomethyl phosphonic acid in water.

Experimental and theoretical influence of multivalent cations on the analysis of glyphosate and aminomethyl phosphonic acid (AMPA) was studied in pure water and in one surface water. The procedure chosen, based on derivatization with FMOC-Cl, HPLC separation, and fluorescence detection, appears highly affected at cations concentrations current in natural waters. A detailed speciation study performed with the VMINTEQ software strongly suggests that the complexes formed between analytes and cations do not dissociate during the reaction and do not react with the derivatization agent, so that only the free forms are derivatized.

Protocols for optimizing MS/MS parameters with an ion-trap GC-MS instrument.

The product ion spectrum allows us to achieve very selective detection of pesticides and to eliminate the ambiguities caused by more conventional analytical approaches. Owing to the enhanced capabilities of GC/MS/MS for multiresidue pesticides, the development of a GC/MS/MS pesticides library will be useful. The aim of this study was to develop a sensitive and specific analytical method for the identification and quantification of compounds without the need of a time-consuming procedure.