TY - JOUR

T1 - Reduction of extraction times in liquid-phase microextraction

AU - Grønhaug Halvorsen, Trine

AU - Pedersen-Bjergaard, Stig

AU - Rasmussen, Knut E.

PY - 2001/9/5

Y1 - 2001/9/5

N2 - Recently, we introduced a simple and inexpensive disposable device for liquid-phase microextraction (LPME) based on porous polypropylene hollow fibres. In the present paper, extraction times were significantly reduced by an increase in the surface of the hollow fibres. The model compounds methamphetamine and citalopram, were extracted from 2.5 ml of urine, plasma, and whole blood after dilution with water and alkalisation with 125 μl of 2 M NaOH though a porous polypropylene hollow fibre impregnated with hexyl ether and into an aqueous acceptor phase consisting of 0.1 M HCl. Two commercially available hollow fibres, which differed in surface area, wall thickness and internal diameter, were compared. An increase in the contact area of the hollow fibre with the sample solution by a factor of approximately two resulted in reduction in equilibrium times by approximately the same factor. Thus, the model compounds were extracted to equilibrium within 15 min from both urine and plasma, and within 30 min from whole blood. For the first time LPME was utilised to extract drugs from whole blood, and the extracts were comparable with plasma both with regard to sample clean-up and extraction recoveries. Extraction recoveries for methamphetamine and citalopram varied from 60 to 100% using the two fibres and the different matrices.

AB - Recently, we introduced a simple and inexpensive disposable device for liquid-phase microextraction (LPME) based on porous polypropylene hollow fibres. In the present paper, extraction times were significantly reduced by an increase in the surface of the hollow fibres. The model compounds methamphetamine and citalopram, were extracted from 2.5 ml of urine, plasma, and whole blood after dilution with water and alkalisation with 125 μl of 2 M NaOH though a porous polypropylene hollow fibre impregnated with hexyl ether and into an aqueous acceptor phase consisting of 0.1 M HCl. Two commercially available hollow fibres, which differed in surface area, wall thickness and internal diameter, were compared. An increase in the contact area of the hollow fibre with the sample solution by a factor of approximately two resulted in reduction in equilibrium times by approximately the same factor. Thus, the model compounds were extracted to equilibrium within 15 min from both urine and plasma, and within 30 min from whole blood. For the first time LPME was utilised to extract drugs from whole blood, and the extracts were comparable with plasma both with regard to sample clean-up and extraction recoveries. Extraction recoveries for methamphetamine and citalopram varied from 60 to 100% using the two fibres and the different matrices.

KW - Citalopram

KW - Extraction times

KW - Liquid-phase microextraction

KW - Methamphetamine

UR - http://www.scopus.com/inward/record.url?scp=0035812470&partnerID=8YFLogxK

U2 - 10.1016/S0378-4347(01)00272-9

DO - 10.1016/S0378-4347(01)00272-9

M3 - Journal article

C2 - 11530980

AN - SCOPUS:0035812470

VL - 760

SP - 219

EP - 226

JO - Journal of Chromatography B: Biomedical Sciences and Applications

JF - Journal of Chromatography B: Biomedical Sciences and Applications

SN - 1387-2273

IS - 2

ER -