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  • Optimisation of the headspace-solid phase microextraction for organomercury and organotin compound determination in sediment and biota.

Optimisation of the headspace-solid phase microextraction for organomercury and organotin compound determination in sediment and biota.

Journal of separation science (2008-02-02)
Alejandra Delgado, Aresatz Usobiaga, Ailette Prieto, Olatz Zuloaga, Alberto de Diego, Juan M Madariaga
ABSTRACT

Headspace solid-phase microextraction was optimised for the simultaneous preconcentration of methylmercury (MeHg+), monobutyltin, dibutyltin, tributyltin, monophenyltin (MPhT), diphenyltin (DPhT), and triphenyltin (TPhT) from sediments and biota. Extraction time (3-24 min), extraction temperature (20-90 degrees C), desorption time (1-10.4 min), desorption temperature (152-260 degrees C), and sample volume (5-22 mL) were simultaneously optimised, while variables such as fibre type (30 microm polydimethylsiloxane, PDMS), pH (acetic acid/sodium acetate, HOAc/NaOAc, 2 mol/L, pH approximately 4.8), the concentration of the derivatisation agent (sodium tetraethylborate, NaBEt4, 0.1% m/v), and the ionic strength (fixed by the buffer solution) were kept constant. The variables were optimised according to the experiments proposed by the MultiSimplex program and the responses were considered in order to establish the optimum conditions. The repeatability (relative standard deviation, RSD, 5-20.6%) and limits of detection (LODs, 0.05-0.97 ng/g) of the overall method were also estimated. The lowest precisions were obtained for DPhT and TPhT. The optimised preconcentration method was applied to the determination of MeHg+), butyl- and phenyltins in certified reference materials (IAEA-405 MeHg+) in estuarine sediment, BCR-646 butyl- and phenyltins in marine sediment, BCR-463 MeHg+ in tuna fish, DOLT-2 MeHg+ in dogfish liver, and BCR-477 butyltins in mussel tissue) by GC with microwave-induced plasma/atomic-emission detection.

MATERIALS
Product Number
Brand
Product Description

Supelco
SPME fiber assembly Polydimethylsiloxane (PDMS), df 30 μm(PDMS, needle size 24 ga, for use with manual holder
Supelco
SPME fiber assembly Polydimethylsiloxane (PDMS), df 30 μm(PDMS, needle size 23 ga, for use with autosampler
Supelco
SPME fiber assembly Polydimethylsiloxane (PDMS), df 30 μm(PDMS, needle size 24 ga, for use with autosampler