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Biomedical subjects

M Bogusz

Publications and source records attributed to M Bogusz.

87 records · Page 5Linked to original sources
PubMedDate not supplied

The determination of carbon monoxide in blood by means of electrochemical pocket gas meter.

The Comopac electrochemical device for CO determination in the workplace was adapted for CO and COHb determination in blood. The method enables the determination of COHb from 1 to 95% in 0.5 mL of blood in 20 min. Comparison of results obtained with the Comopac, spectrophotometry, and gas chromatography showed comparable accuracy and precision. The specificity of the electrochemical method was better than spectrophotometry and comparable with gas chromatography.

Carbon Monoxide↗
PubMedDate not supplied

Use of corrected retention indices based on 1-nitroalkane and alkyl arylketone scales for HPLC identification of basic drugs.

Sixteen basic drugs were examined by HPLC (gradient elution in acetonitrile/phosphate buffer, pH 3.2, containing 0.05% nonylamine) with six different ODS-silica columns. The retention indices (RI) were calculated with alkyl arylketone and 1-nitroalkane scales and were subjected to correction, which enabled comparison of results from commercially different column packing materials. The correction procedure was successful for the 1-nitroalkane scale. The scale based on alkyl arylketones was of less use for basic drugs, because some of them eluted earlier than the first reference homologue. This made impossible the proper calculation and correction of RI values for drugs such as cocaine, diphenhydramine, doxepin, and promethazine. The correction procedure of RI values calculated against the series of 1-nitroalkanes is recommended as a method of standardization of HPLC data.

Alkanes↗
PubMedDate not supplied

Influence of elution conditions on HPLC retention index values of selected acidic and basic drugs measured in the 1-nitroalkane scale.

The retention indices (RI) of 62 acidic, neutral, and basic drugs were determined by HPLC under isocratic conditions (20, 40, and 60% acetonitrile-phosphate buffer, pH 3.2, containing 0.05% nonylamine) and with gradient elution (5-70% acetonitrile-phosphate buffer pH 3.2, containing 0.05% nonylamine). The RI values of acidic drugs and earlier-eluting basic drugs decreased distinctly with increasing concentrations of acetonitrile. For the later-eluting basic drugs, the opposite trend was observed. The RI data obtained with different isocratic conditions and with gradient elution were not transferable. The study shows the importance of careful standardization of elution conditions for interlaboratory comparison.

Acetonitriles↗
PubMedDate not supplied

Standardized HPLC/DAD system, based on retention indices and spectral library, applicable for systematic toxicological screening.

An HPLC gradient elution system is applied for general toxicological screening. The use of a diode array detector with library software allows storage of retention parameters, UV spectra, and peak quality parameters of examined substances. The developed library is used for automatic identification of compounds. The retention indices of 225 substances are measured in the 1-nitroalkane scale. These data may be of interlaboratory use because of an appropriate correction procedure. Long-term reproducibilities of retention behavior of 1-nitroalkanes and correction standards are satisfactory. The conditions of interlaboratory use are discussed.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Influence of biological matrix on chromatographic behavior and detection of selected acidic, neutral, and basic drugs examined by means of a standardized HPLC-DAD system.

Human serum, autopsy blood, and liver samples were extracted by means of liquid-liquid extraction at acidic and at basic pH and at basic pH following acid hydrolysis. Six selected basic and six selected acidic or neutral drugs were added to the extracts. The spiked and blank samples were examined by means of reversed-phase high-performance liquid chromatography (HPLC) under standardized conditions using diode array detection. The retention index (RI) values of drugs were determined using a 1-nitroalkane scale and secondary standards. The RI values were virtually unaffected by biological matrix. On the other hand, the detection of some substances may be impaired by matrix peaks occurring regularly in biological extracts. The retention index values and UV spectra of three identified (phenethylamine, tryptamine, and indole) and nine unidentified substances were included in an HPLC database.

Autopsy↗
PubMedDate not supplied

Identification power of a standardized HPLC-DAD system for systematic toxicological analysis.

High-performance liquid chromatography with photodiode-array detection (HPLC-DAD) provides two identification parameters: retention and UV spectral data. The identification power of these two parameters, expressed in standardized form (retention index and absorption maximum with the highest wavelength), is calculated using two approaches: discriminating power (DP) and mean list length (MLL). Our own HPLC database, which comprises data for more than 370 substances, is used as the basis of calculations. The identification power of both parameters applied separately is low but increases substantially when the combination of retention and spectral data is applied. Additionally, the DP and MLL values obtained for 56 acidic or neutral and 76 basic drugs examined by means of HPLC-DAD and other analytical methods (thin-layer chromatography, gas chromatography (GC), and ultraviolet (UV) detection) are compared. The on-line combination of HPLC retention index values and UV spectra, registered by means of DAD, creates an identification system in which the identification potential is slightly lower than the off-line combination of capillary GC and UV spectroscopy.

Chromatography, Gas↗
PubMedDate not supplied

Applicability of capillary gas chromatography to systematic toxicological analysis: occurrence of concentration-dependent retention behavior.

The retention behavior for a selection of acidic, neutral, and basic drugs was examined on four fused silica capillary columns in a splitless injection mode. Mixtures of n-alkanes and diisopropylamino-alkanes were also analyzed. The concentrations used ranged from 0.25-1000 ng/microL and injection volumes were either 2 or 4 microL. This corresponded to quantities of 1-4000 ng injected on the column. All substances showed concentration-dependent behavior: after being nearly constant or showing a decrease at low concentrations, retention times markedly increased when concentrations exceeded about 100 ng/microL (400 ng injected). At very high concentrations, peak splitting occurred. In the more pronounced cases, the differences caused by this concentration effect could reach values of over 100 retention-index units.

Chemical Phenomena↗
PubMedDate not supplied

Impact of biological matrix and isolation methods on detectability and interlaboratory variations of TLC Rf-values in systematic toxicological analysis.

The retention behavior of eight basic and neutral drugs, extracted from plasma, blood, and liver by five different methods (XAD-2, Extrelut, Elut-X, Elut-C18, chloroform) and developed in three chromatographic systems [MeOH, Me OH:BuOH:NaBr, CHCl3:MeOH (KOH)] was observed in parallel in two laboratories. The corrected Rf-values were compared with reference data from a data base with data for pure drugs. The biological matrix and/or the extraction severely lowered the precision and, to a lesser extent, the accuracy of the Rf-values as compared to pure drug data and to reference Rf-values. The intra- and interlaboratory variation was smallest in the MeOH system and largest in the CHCl3:MeOH (KOH) system. The observed irreproducibility is caused by the biological matrix (extraction has a large negative impact on the potentials of TLC in identification procedures). Precision and accuracy of extracted drugs were independent of the biological matrix and on the extraction method used.

Chemistry, Pharmaceutical↗
PubMedDate not supplied

Impact of biological matrix, drug concentration, and method of isolation on detectability and variability of retention index values in gas chromatography.

The retention indices of eight basic and neutral drugs extracted from plasma, blood, or liver homogenate by six different methods were calculated using temperature-programmed gas chromatography on OV-1 and SE-30 columns. Two concentrations were applied: 1 and 50 mg/L, respectively. The type of extraction had great influence on recovery and analytical background. The retention indices tended to be slightly concentration-dependent in that they were somewhat lower at higher drug concentration. Neither the biological sample nor the type of extraction exerted significant influence on scatter and mean value of the retention indices.

Chromatography, Gas↗
PubMedDate not supplied

Erratic data in thin layer chromatography due to anomalous behavior of correction standards.

Correction of crude thin layer chromatographic data usually enables a reliable comparison with reference data bases. However, when the correction standards are not spotted in the right positions, the calculation may produce false results if anomalous migration occurs. This was observed in the case of acidic and neutral drugs developed in the chloroform-methanol (9:1) system.

Chromatography, Thin Layer↗