Determination of drugs in biological fluids by high-performance liquid chromatography with on-line sample processing

Oertel, Reinhard; Richter, Klaus; Gramatté, T; Kirch, Wilhelm

doi:10.1016/s0021-9673(97)00966-7

Cited by 47 publications

(23 citation statements)

References 18 publications

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“…In recent years the use of special supports possessing restricted access media (RAM) for the direct injection of complex biological matrices has been explored. [8][9][10][11][12][13] As the aim of this work was to develop an enantioselective HPLC assay that would be simple and reliable for quantification of metyrapol enantiomers in the presence of metyrapone in plasma, with on-line sample preparation, the use of a RAM BSA column coupled to an amylose tris(3,5-dimethoxyphenylcarbamate) chiral stationary phase was taken into account. Menezes and Felix 6 reported the preparation and application of a RAM BSA column for the analysis of pesticides in milk by direct injection.…”

Section: Resultsmentioning

confidence: 99%

Determination of the plasma levels of metyrapone and its enantiomeric metyrapol metabolites by direct plasma injection and multidimensional achiral–chiral chromatography

et al. 2002

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The development and validation of a direct injection high-performance liquid chromatographic (HPLC) method, with column switching, for the determination of metyrapol enantiomers and metyrapone in human plasma is described. The system used in this work was composed of a restricted access media (RAM) bovine serum albumin (BSA) octyl column coupled to an amylose tris(3,5-dimethoxyphenylcarbamate) chiral column. Water was used as eluent for the first 5 min at a flow rate of 1.0 ml/min for the elution of the plasma proteins and then acetonitrile-water (30:70 v/v) for the transfer and analysis of metyrapol enantiomers and metyrapone, which were detected by UV at lambda = 260 nm. The total analysis time was about 32 min. The calibration curves for each enantiomer and for the metyrapone were linear in the ranges 0.075-0.75 microg/ml and 0.150-1.50 microg/ml, respectively. Recoveries, intra- and interday precision and accuracy were determined using three quality controls, one low (0.18 microg/ml), one medium (0.75 microg/ml), and one high (1.35 microg/ml) plasma concentration. Quantitative recoveries and good precision and accuracy were obtained. The limit of quantitation were 0.045 microg/ml for both enantiomers and for the metyrapone.

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Section: Resultsmentioning

confidence: 99%

Determination of the plasma levels of metyrapone and its enantiomeric metyrapol metabolites by direct plasma injection and multidimensional achiral–chiral chromatography

et al. 2002

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“…Thus, there has been a growing interest towards the development of simpler methods and improvement of the already existing sample protocols in terms of sensitivity, selectivity and simplicity of sample preparation. In some analytical areas, such as drug analysis, direct injection of a cell culture medium into the liquid chromatography system has been achieved by substituting the SPE and LLE steps for an automated on-line two-column-switching pre-concentration system [7]. Although, this proposed system is a reliable alternative to reduce sample preparation by enabling effective clean-up of cell cultures media, the required equipment is rather complex, involving a combination of several concentration and separation columns, pumps and switching valves under computer control.…”

Section: Introductionmentioning

confidence: 99%

Direct Injection of Redissolved Cell Culture Media into a Single-Column Liquid Chromatography Coupled to Mass Spectrometry for the Measurement of PGE2

Araujo¹,

Du²,

Nguyen³

et al. 2008

TOACJ

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Abstract:The traditional approach to assessing eicosanoids in cell cultures by liquid or gas chromatography coupled to mass spectrometry involves time-consuming procedures such as derivatisation, degradation, solid-phase extraction, liquidliquid extraction, thin layer chromatography and sometimes, combination of all these procedures prior to the injection of the sample in the chromatography system. The performance of a method that allows the direct injection of redissolved cell culture media into a single-column liquid chromatography instrument coupled to mass spectrometry is evaluated. The external standard calibration curves were linear between 1-50 ng/ml for Williams' medium E and L-15 medium. The limit of detection and quantification were 0.5 and 1 ng/ml in both media respectively. The recovery values were 98.6% for Williams' medium E and 100.3% for L-15 medium. The internal standard method was not used for quantitative purposes due to the variability of the response factor. The proposed method has potential for broad implementation in monitoring biomarkers in cell cultures.

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“…Restricted access material (RAM) pre-columns, acting by size exclusion, exclude macromolecules from the sample prior to its reaching the chromatographic column. RAM columns have been used in the direct analysis of benzodiazepines [7], oxazilidinones [8], and several other drugs and metabolites [9,10] in serum, plasma, and urine.…”

Section: Introductionmentioning

confidence: 99%

Polyethylene powder microcolumn for protein separation prior to HPLC plasma analysis. Application to the determination of copper and zinc

Mendonça

Nascimento²,

Bohrer

2003

J of Separation Science

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Polyethylene powder microcolumn for protein separation prior to HPLC plasma analysis. Application to the determination of copper and zinc Three different types of polyethylene powder (PE) were investigated with regard to their ability to adsorb proteins, with the goal of accomplishing plasma deproteinization for further HPLC analysis. Best results were obtained with ultrahigh molecular mass polyethylene The proteins retained by the PE powder were washed out of the column with methanol followed by water. A chromatographic system with the PE column as pre-column was set up for the determination of copper and zinc in plasma. The plasma sample was injected into the chromatograph, and, on passage through the pre-column, the proteins were adsorbed onto the PE. While a protein-free eluate was being sent to the analytical column, by switching the pump channels the pre-column was being flushed with methanol and water to elute the adsorbed proteins. After washing, the pre-column was conditioned with the eluent to receive the next sample. Copper and zinc determination was performed by HPLC with photometric detection after post-column derivatization with 4-(2-pyridylazo)resorcinol (PAR). The results, compared with those from flame atomic absorption spectrometry, showed that zinc can be determined by direct injection of the sample, but copper only after dilution. As the copper recovery from undiluted samples was about 65%, it was probably retained together with the proteins. However, on previous dilution of the sample with the eluent (acidic solution of lactic acid) the copper recovery reached 100%. The proposed method is suitable for the HPLC determination of copper and zinc in plasma samples without further sample treatment, in about 30 min.

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Determination of drugs in biological fluids by high-performance liquid chromatography with on-line sample processing

Cited by 47 publications

References 18 publications

Determination of the plasma levels of metyrapone and its enantiomeric metyrapol metabolites by direct plasma injection and multidimensional achiral–chiral chromatography

Determination of the plasma levels of metyrapone and its enantiomeric metyrapol metabolites by direct plasma injection and multidimensional achiral–chiral chromatography

Direct Injection of Redissolved Cell Culture Media into a Single-Column Liquid Chromatography Coupled to Mass Spectrometry for the Measurement of PGE2

Polyethylene powder microcolumn for protein separation prior to HPLC plasma analysis. Application to the determination of copper and zinc

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