Biomedical subjects

Astrid Sanusi

Publications and source records attributed to Astrid Sanusi.

3 recordsLinked to original sources

PubMed2004

Advanced method using microwaves and solid-phase microextraction coupled with gas chromatography-mass spectrometry for the determination of pyrethroid residues in strawberries.

A microwave-assisted desorption method was developed and coupled with solid-phase microextraction and GC-MS for the analysis of pyrethroid residues in strawberries. In the first step, pyrethroid analytes were desorbed from the whole fruits in an aqueous acetonitrile solution at 50% under microwave assistance, so preventing these compounds to be captured with strong matrix effects by endogenous constituents. Then, the 100 microm poly(dimethylsiloxane)-coated fibre was exposed for 30 min in the obtained extracting solution. Calibration curves, realised from blank strawberries spiked at different concentrations with standards, showed a linear range between 1 microg/kg and 250 microg/kg with r2 > 0.992 and variation coefficients below 15%. Limits of detection and quantitation were found lower than 14 microg/kg and 40 microg/kg, respectively. Observed analysis results by using this method and relative to field incurred strawberry samples were also compared to those obtained by two accredited trading laboratories using traditional methods.

Adsorption↗

PubMed2004

Multiresidue method using SPME for the determination of various pesticides with different volatility in confined atmospheres.

An analytical method is described for assessing the vapour concentration of 11 pesticides (bioallethrin, chlorpyriphos methyl, folpet, malathion, procymidone, quintozene, chlorothalonil, fonofos, penconazole and trimethacarb) in confined atmospheres (e.g. a greenhouse after pesticide application). This study is a successful extension of a method previously developed by the authors for dichlorvos to much less volatile pesticides. Sampling was performed by using polydimethylsiloxane-solid phase micro-extraction (PDMS-SPME) fibres immersed in a 250-mL sampling flask through which air samples were dynamically pumped from the analysed atmosphere. After a 40-min sampling duration, samples were analysed by GC/MS. Calibration was performed from a vapour-saturated air sample. The linearity of the observed signal versus pesticide concentration in the vapour phase was proved from spiked liquid samples whose headspace concentrations were measured by using the proposed method. This procedure gave calibration curves with regression coefficients ( R(2)) greater than 0.98, and the repeatability of these measurements was found with RSDs of 1.9-7.6%. As a field application test, this analysis procedure was used for the determination of gaseous procymidone concentrations as a function of time in the atmosphere of an experimental 8-m(2) and 20-m(3) greenhouse. The pesticide was sprayed according to real cultivation conditions, and measurements were made for 80 h after application (8 measurements). The observed concentrations found ranged from 200 to 500 micro g m(-3), thus indicating the level of contamination of the air breathed by people in such working conditions.

Journal Article↗

PubMed2003

Pesticide vapours in confined atmospheres. Determination of dichlorvos by SPME-GC-MS at the microg m(-3) level.

A method based on SPME is described for assessing the gaseous dichlorvos concentration in confined atmospheres like a greenhouse after a pesticide application. Sampling was made by using SPME with PDMS fibres immersed into a 250 mL sampling flask into which air samples were dynamically pumped from the analysed atmosphere. Sampling duration was 40 min and samples were then analysed by GC-MS. Calibration was performed from a vapour saturated air sample and gas phase diluted samples, and this procedure afforded a curve with a regression coefficient (R2) higher than 0.98. The repeatability of these measurements was observed with an RSD of 2.5%. This analysis procedure was then applied for the determination of gaseous dichlorvos concentrations versus time, in the atmosphere of an experimental 8 m2 and 20 m3 greenhouse. The pesticide was sprayed according to real cultivation conditions and measurements were made from 2 up to 74 h after application affording observed concentrations in the range of decades and hundreds of microg m(-3) (corresponding limits of detection and quantification were found at the level of a few microg m(-3)).

Air Movements↗