Skip to Content
Merck
  • Sensitivity enhancement in direct coupling of supported liquid membrane extractions to capillary electrophoresis by means of transient isotachophoresis and large electrokinetic injections.

Sensitivity enhancement in direct coupling of supported liquid membrane extractions to capillary electrophoresis by means of transient isotachophoresis and large electrokinetic injections.

Journal of chromatography. A (2015-03-10)
Pavla Pantůčková, Pavel Kubáň, Petr Boček
ABSTRACT

Enhanced sensitivity for determination of basic drugs in body fluids was achieved by in-line coupling of extraction across supported liquid membrane (SLM) to large electrokinetic injection and transient isotachophoresis-capillary zone electrophoresis (tITP-CZE) in commercial CZE instrument. Twelve cm long tITP plug of 300mM ammonium acetate was formed in the separation capillary just before the electrokinetic injection of acceptor solution containing nortriptyline, haloperidol and loperamide extracted across the SLM. The tITP plug ensured efficient stacking and preconcentration of the injected basic drugs due to the tITP action of ammonium and the drugs were then separated by CZE using 5.2M acetic acid as background electrolyte. No interferences were observed from highly-abundant body fluid species (NaCl and human serum albumin) due to the excellent clean-up properties of SLMs and analytical sensitivity increased up to 340 times compared to SLM extractions coupled in-line to CZE with standard hydrodynamic injections. The SLM-tITP-CZE method was characterized by good repeatability (RSDs of peak areas below 7.8%), linearity over two orders of magnitude (r(2) better than 0.994) and limits of detection (defined as 3×S/N) between 3 and 45μg/L. Interfacing of SLM extractions to CZE instrumentation was achieved by low-cost, disposable micro-extraction devices, which can be routinely prepared in every analytical laboratory. These devices eliminated sample carry-over, minimized the need for manual sample handling and ensured fully automated determination (including extraction, injection, preconcentration and separation) of the three basic drugs in 20μL of untreated body fluids.

MATERIALS
Product Number
Brand
Product Description

Supelco
5α-Androstan-17β-ol-3-one, VETRANAL®, analytical standard
Sigma-Aldrich
Ethyl alcohol, Pure, 200 proof, anhydrous, ≥99.5%
Sigma-Aldrich
Pyrvinium pamoate salt hydrate, ≥98% (HPLC)
Sigma-Aldrich
Ethanol, purum, secunda spirit, denaturated with 2% 2-butanone, S15, ~96% (based on denaturant-free substance)
Supelco
Ethanol, standard for GC
Sigma-Aldrich
Ethyl alcohol, Pure, 190 proof, ACS spectrophotometric grade, 95.0%
Sigma-Aldrich
Ethyl alcohol, Pure, 190 proof, meets USP testing specifications
Supelco
Ethanol standards 10% (v/v), 10 % (v/v) in H2O, analytical standard
Sigma-Aldrich
Ethanol, BioUltra, for molecular biology, ≥99.8%, (absolute alcohol, without additive, A15 o1)
Sigma-Aldrich
Ethanol, for residue analysis
Sigma-Aldrich
Ethanol, tested according to Ph. Eur.
Sigma-Aldrich
Ethyl alcohol, Pure, 200 proof, ACS reagent, ≥99.5%
Sigma-Aldrich
Ethanol, ACS reagent, prima fine spirit, without additive, F15 o1
Sigma-Aldrich
Ethyl alcohol, Pure, 160 proof, Excise Tax-free, Permit for use required
Sigma-Aldrich
Ethyl alcohol, Pure, 200 proof, ACS reagent, meets USP testing specifications, Excise Tax-free, Permit for use required
Millipore
Bifido Selective Supplement B, suitable for microbiology
Sigma-Aldrich
Ethyl alcohol, Pure, 190 proof, ACS reagent, meets USP testing specifications, Excise Tax-free, Permit for use required
Sigma-Aldrich
Ethanol, puriss. p.a., absolute, ≥99.8% (GC)
USP
Glacial acetic acid, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Ethyl alcohol, Pure, 200 proof, meets USP testing specifications
Sigma-Aldrich
Ethyl alcohol, Pure 200 proof, for molecular biology
Sigma-Aldrich
Ethyl alcohol, Pure, 200 proof
Sigma-Aldrich
Ethanol, purum, absolute ethanol, denaturated with 1% cyclohexane, A15 CYCLO1, ≥99.8% (based on denaturant-free substance)
Sigma-Aldrich
Ethanol, purum, fine spirit, denaturated with 2% 2-butanone, F25 MEK1, ~96% (based on denaturant-free substance)
Sigma-Aldrich
Ethanol, purum, absolute ethanol, denaturated with 2% 2-butanone, A15 MEK1, ≥99.8% (based on denaturant-free substance)
Sigma-Aldrich
Ethanol, purum, fine spirit, denaturated with 4.8% methanol, F25 METHYL1, ~96% (based on denaturant-free substance)
Sigma-Aldrich
Ethanol, purum, absolute ethanol, denaturated with 4.8% isopropanol, A15 IPA1, ≥99.8% (based on denaturant-free substance)
Supelco
Dehydrated Alcohol, Pharmaceutical Secondary Standard; Certified Reference Material
Haloperidol, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Acetic acid-12C2, 99.9 atom % 12C