On-line membrane preconcentration for continuous monitoring of trace pharmaceuticals

Bishop, Edmund J.; Mitra, Somenath

doi:10.1016/j.jpba.2004.09.040

Cited by 18 publications

(7 citation statements)

References 15 publications

(20 reference statements)

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“…× 0.356 mm i.d. fiber with a nitrogen pressure of 0.7 bar, resulting in an enrichment of a factor 8 in a residence time of 0.4 min. In the present study, a pressure of 0.3 bar was applied, resulting in enrichment factors of up to 6 at a residence time of 1.2 min (see Fig.…”

Section: Resultsmentioning

confidence: 99%

A membrane microcontactor as a tool for integrated sample preparation

Hereijgers

Callewaert

Breugelmans

et al. 2012

J of Separation Science

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A membrane microcontactor suitable to perform liquid-liquid extraction as well as evaporation in order to conduct enrichment steps in sample preparation of organ samples has been designed, fabricated, and characterized. Spacers of 100- or 200-μm high were constructed in a metal substrate with a channel width of 13 mm and the extraction kinetics in these channels was evaluated. The spacers were designed such that at the entrance and exit region a uniform flow distribution could take place and that a uniform flow profile could be guaranteed along the channel, hence allowing a large freedom in sample volume to be processed. The extraction and evaporation kinetic behavior of the device was first evaluated by extraction of a drug candidate (4-(2,5-dimethyl-pyrrol-1-y1)-2-hydroxybenzoic acid). To evaluate the device under more challenging working conditions, a homogenized mice kidney sample containing the drug candidate that was administered in life condition was cleaned and enriched with the extraction and evaporation modules and characterized by high-performance liquid chromatography, yielding an overall analysis time of 15-20 min per sample only. The system has the potential to be operated in a continuous fashion, making it appealing to be implemented in screening or high-throughput applications.

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Section: Resultsmentioning

confidence: 99%

A membrane microcontactor as a tool for integrated sample preparation

Hereijgers

Callewaert

Breugelmans

et al. 2012

J of Separation Science

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“…Vapor pressure increases exponentially with increasing temperature according to Antoine's equation 50 and the diffusion coefficient follows an Arrhenius type expression. 51 Since MD is a thermal process, heat transfer plays an important role. It is also well established that CNTs have high thermal conductivity, which reduces the temperature gradient in the membranes, thus reducing condensation and allowing more vapor to permeate through the pores.…”

Section: Resultsmentioning

confidence: 99%

Carbon nanotube enhanced membrane distillation for online preconcentration of trace pharmaceuticals in polar solvents

Gethard

Mitra

2011

Analyst

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Carbon nanotube enhanced membrane distillation (MD) is presented as a novel, online analytical preconcentration method for removing polar solvents thereby concentrating the analytes, making this technique an alternate to conventional thermal evaporation. In a carbon nanotube immobilized membrane (CNIM), the CNTs serve as sorbent sites and provide additional pathways for enhanced solvent vapor transport, thus enhancing preconcentration. Enrichment using CNIM doubled compared to membranes without CNTs, while the methanol flux and mass transfer coefficients increased by 61% and 519% respectively. The carbon nanotube enhanced MD process showed excellent precision (RSD of 3-5%), linearity, and the detection limits were in the range of 0.001 to 0.009 mg L(-1) by HPLC analysis.

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“…The Nafion membranes are a copolymer of tetrafluoroethylene and perfluoro-3,6-dioxa-4methyl-7-otene-sulfonic acid, and are highly polar. 23 MWCNTs (multiwalled carbon nanotubes) were obtained from Cheap Tubes Inc. HPLC grade acetonitrile (Fisher Scientific, NJ, USA) was used as mobile phase in HPLC analysis and deionized (DI) water was obtained using a Millipore Gradient A10 water purification system (Millipore CO., Bedford, MA, USA).…”

Section: Chemicals and Materialsmentioning

confidence: 99%

Carbon nanotube immobilized polar membranes for enhanced extraction of polar analytes

Bhadra

Mitra

2012

Analyst

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We demonstrate for the first time that carbon nanotubes (CNTs) can be readily immobilized on the surface of a solid polymeric membrane which can lead to enhanced enrichment factor and extraction efficiency. The effectiveness of the CNT mediated process is demonstrated by micro-scale membrane extraction via direct solvent enrichment of polar and nonpolar organics. The enrichment factor measured as the ratio of concentrations in the acceptor to the donor phases was as high as 282 and the enhancement over the unmodified membrane was as much as 92%. In addition, the solvent retention in the carbon nanotube immobilized membrane (CNIM) increased by as much as 29%. Overall, the CNT incorporation provided enhanced solute transport and thus led to overall performance enhancement.

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On-line membrane preconcentration for continuous monitoring of trace pharmaceuticals

Cited by 18 publications

References 15 publications

A membrane microcontactor as a tool for integrated sample preparation

A membrane microcontactor as a tool for integrated sample preparation

Carbon nanotube enhanced membrane distillation for online preconcentration of trace pharmaceuticals in polar solvents

Carbon nanotube immobilized polar membranes for enhanced extraction of polar analytes

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