The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Franco Tagliaro - One of the best experts on this subject based on the ideXlab platform.
-
lactate determination in human Vitreous Humour by capillary electrophoresis and time of death investigation
Electrophoresis, 2020Co-Authors: Anna Bertaso, Elio Franco De Palo, Vito Cirielli, Franco TagliaroAbstract:: Forensic inquests, particularly in assessing time since death currently recognises the importance of the analysis of Vitreous Humour (VH) biomarkers. Present research, studies and validates the determination of Lactate (La) in VH by capillary zone electrophoresis (CZE) with indirect UV detection. The background electrolyte (BGE) (pH 8.9) consisted of Tris buffer (37 mM) containing 4-methoxybenzoic acid (4 mM) and alkyl-trimethyl-ammonium bromide (1.2 mM). Each VH specimen was diluted with a butyric acid solution (Internal Standard (IS) 0.057 mM) and La and butyrate were separated within 3-5 min (30kV). The La LOQ and LOD were 4 and 2 mM, respectively. The calibration curve linearity ranged from 4 to 80 mM; intra and inter runs precisions were less than 10% for standard as well as for VH specimen, respectively. To investigate post mortem interval (PMI) and VH lactate level correlation human VH specimens were collected during autopsy (n = 40) and stored at -20 °C until assay. La levels ranged from 16 to 42 mM; PMI values ranged from 10 to 141 hours. La (mM) and PMI (h) correlation was statistically significant (r2 = 0.527; p<0.05). In conclusion, the present CZE analysis is efficacious to determine VH La as a biomarker for PMI investigation. This article is protected by copyright. All rights reserved.
-
a new method for the determination of ammonium in the Vitreous Humour based on capillary electrophoresis and its preliminary application in thanatochemistry
Clinical Chemistry and Laboratory Medicine, 2019Co-Authors: Rossella Gottardo, Federica Bortolotti, Covadonga Palacio, Kseniia M Shestakova, Natalia E Moskaleva, Franco TagliaroAbstract:: Background Although the post-mortem increase of ammonium in biological fluids is well known, ammonium analysis in Vitreous Humour has never been used in recent times for the determination of the post-mortem interval. The present work represents a new application of capillary electrophoresis with indirect UV detection in the field of forensic analysis. Methods The electrophoretic separation was carried out in a running buffer made of 5 mM imidazole, 5 mM 18-crown-6 ether and 6 mM d,l-α-hydroxybutyric acid (HIBA). To overcome the lack of optical absorption of ammonium, indirect UV detection was applied. The used wavelength was 214 nm. Results The method showed good linearity in the concentration range from 0.16 to 5.0 mM. The limit of detection, 0.039 mmol/L, was established on the basis of the linearity curve. Precision and bias studies carried out on the pure ammonium solutions and in real biological samples, revealed %RSDs well below 20%. A preliminary application to real cases where the death time was precisely known (14 bodies) was carried out plotting Vitreous Humour ammonium vs. post-mortem interval with a resulting good linear correlation until 100 h post-mortem. Conclusions After validation in real cases, the present method can become a powerful tool to unravel one of the most challenging issues of forensic investigation: determination of the time of death.
-
capillary zone electrophoresis and artificial neural networks for estimation of the post mortem interval pmi using electrolytes measurements in human Vitreous Humour
International Journal of Legal Medicine, 2002Co-Authors: G Bocazbeneventi, G Manetto, Franco Tagliaro, Federica Bortolotti, Josef HavelAbstract:Determination of electrolyte concentrations (mainly potassium) in Vitreous Humour has long been considered an important tool in human death investigations for the estimation of the post-mortem interval (PMI). On the basis of its well known potential in ion analysis, capillary zone electrophoresis (CZE) has recently been applied to achieve a rapid and simultaneous determination of inorganic ions in this extracellular fluid. In the present work, artificial neural networks (ANN) were applied for modelling of the relationship of multicomponent CZE analysis of K+, NH4+, Na+, and Ba2+ ions in Vitreous Humour with PMI. In a study based on 61 cases with different causes of death and a known PMI ranging from 3 to 144 h, the use of ANNs considering all inorganic ion data from the human Vitreous Humour, achieved a substantial improvement of post-mortem interval prediction. Good linear correlation was observed (r2 = 0.98) and in comparison to the traditional linear least squares (LLS) method applied only to K+ levels in the Vitreous Humour, the prediction of PMI with ANN was improved by a factor of 5 from ≈± 15 h to less than 3 h.
-
potassium concentration differences in the Vitreous Humour from the two eyes revisited by microanalysis with capillary electrophoresis
Journal of Chromatography A, 2001Co-Authors: Franco Tagliaro, G Manetto, V L Pascali, Federica Bortolotti, Francesca Cittadini, M MarigoAbstract:This paper presents a study of the variability of potassium concentrations in the Vitreous Humour of the two eyes of the same body at identical postmortem interval. The study was carried out by collecting microsample amounts (50 μl) of Vitreous Humour and by using an original method of capillary electrophoresis with indirect detection. The electrophoretic separations were carried out in a pH 4.5 running buffer composed of 5 mmol/l imidazole, 5 mmol/l 18-crown-6 ether and 6 mmol/l α-hydroxybutyric acid. Detection was by indirect UV absorption at 214 nm. Vitreous Humour samples were collected from 57 medico–legal autopsies or external examinations of cases of sudden natural or violent deaths. All samples prior to analysis were diluted 1:20 with a 40 μg/ml aqueous solution of barium, the used internal standard, and finally injected by nitrogen pressure. The mean concentrations of potassium measured in the two eyes of all the cases included in the present study ranged from 4.1 to 23.5 mmol/l with the postmortem interval values varying from 7 to 144 h. A highly significant (P<0.0001) linear correlation was found between these two parameters as described by the equation: y=0.1698x+2.3587, r=0.89. The intra-eye variability of potassium concentrations was low with an average RSD of 3.89% (±1.83 SD) (48 eyes, five samples per eye). No statistically significant difference was found between the potassium concentrations in the two eyes of the same subject in a group of 24 cases, excepting a single case.
-
capillary zone electrophoresis of potassium in human Vitreous Humour validation of a new method
Journal of Chromatography B: Biomedical Sciences and Applications, 1999Co-Authors: Franco Tagliaro, G Manetto, Federica Bortolotti, Francesca Cittadini, Daniela Marchetti, M MarigoAbstract:: The analysis of potassium in the Vitreous Humour has long been regarded as an important tool in medicolegal and forensic toxicological investigation, particularly for the determination of the post-mortem interval. The present work was aimed at the optimisation and validation of a reliable, simple and fast capillary electrophoresis method for potassium analysis in the human Vitreous Humour with indirect UV detection at a wavelength of 214 nm. Electrophoretic separations were carried out in a running buffer comprising 5 mM imidazole, 5 mM 18-crown-6 ether and 6 mM D,L alpha-hydroxybutyric acid (HIBA), adjusted to pH 4.5. Constant voltage runs were carried out by applying a voltage of 500 V/cm at 25 degrees C. The samples were injected in the hydrodynamic mode at the anodic end of the capillary (0.5 p.s.i. for 10 s; 1 p.s.i. = 6894.76 Pa). The method showed good linearity in the concentration range from 6.5 mM to 16.25 microM, with an r2 value of 0.9994. The limit of detection, based on a signal-to-noise ratio of three, was 9.0 microM. Absolute intra-day RSDs of migration times were <0.40%, while the day-to-day values were < or =1.72%. Absolute peak area reproducibility was always better than 2.50%. A comparison of capillary electrophoresis with flame photometry on twelve real autopsy samples showed an excellent correlation with an r2 value of 0.9333. A preliminary application to real cases (20 subjects) was carried out plotting Vitreous Humour potassium vs. post-mortem interval with a resulting r2 of 0.904 and a Y-intercept of 4.75 mM, in agreement with the existing literature.
S O Kayaalp - One of the best experts on this subject based on the ideXlab platform.
-
human aqueous and Vitreous Humour levels of ciprofloxacin following oral and topical administration
Eye, 1999Co-Authors: Osman Cekic, Cosar Batman, Umit Yasar, N E Basci, A Bozkurt, S O KayaalpAbstract:Purpose To assess aqueous and Vitreous Humour ciprofloxacin concentrations following oral and topical administration of ciprofloxacin in patients with non-inflamed cornea and an intact crystalline lens, and to compare the concentrations of the drug given by either route. Methods In this prospective study, 34 patients undergoing pars plana vitrectomy for various ocular pathologies were divided into two groups. Eighteen patients received 2 drops of 0.3% ophthalmic solution of ciprofloxacin every 30 min for 3 h and then every 60 min for the next 3 h, and 16 patients received a single oral dose of 1000 mg ciprofloxacin 6 h before surgery. The aqueous and Vitreous Humour samples were simultaneously harvested after oral or topical administration during pars plana vitrectomy to assess penetration of the drug. These samples were assayed for ciprofloxacin concentrations by a method described previously by us using high-performance liquid chromatography. Results The aqueous and Vitreous Humour levels of ciprofloxacin were 0.59 ± 0.06 μg/ml (mean ± SEM) and 0.64 ± 0.06 μg/ml after oral and 0.44 ± 0.07 μg/ml and 0.22 ± 0.04 μg/ml after topical ciprofloxacin administration, respectively. Aqueous Humour levels were not statistically significantly different following oral and topical administration (p = 0.069). However, the Vitreous level of the drug after oral administration was significantly higher than that after topical administration (p<0.001). Conclusion Ocular bioavailability of ciprofloxacin in aqueous Humour following oral and topical administration is found to be similar when the drug was applied as described above. Penetration of ciprofloxacin into Vitreous Humour is less than that into aqueous Humour after topical administration.
-
Human aqueous and Vitreous Humour levels of ciprofloxacin following oral and topical administration.
Eye (London England), 1999Co-Authors: Osman Cekic, Cosar Batman, Umit Yasar, N E Basci, A Bozkurt, S O KayaalpAbstract:To assess aqueous and Vitreous Humour ciprofloxacin concentrations following oral and topical administration of ciprofloxacin in patients with non-inflamed cornea and an intact crystalline lens, and to compare the concentrations of the drug given by either route. In this prospective study, 34 patients undergoing pars plana vitrectomy for various ocular pathologies were divided into two groups. Eighteen patients received 2 drops of 0.3% ophthalmic solution of ciprofloxacin every 30 min for 3 h and then every 60 min for the next 3 h, and 16 patients received a single oral dose of 1000 mg ciprofloxacin 6 h before surgery. The aqueous and Vitreous Humour samples were simultaneously harvested after oral or topical administration during pars plana vitrectomy to assess penetration of the drug. These samples were assayed for ciprofloxacin concentrations by a method described previously by us using high-performance liquid chromatography. The aqueous and Vitreous Humour levels of ciprofloxacin were 0.59 +/- 0.06 microgram/ml (mean +/- SEM) and 0.64 +/- 0.06 microgram/ml after oral and 0.44 +/- 0.07 microgram/ml and 0.22 +/- 0.04 microgram/ml after topical ciprofloxacin administration, respectively. Aqueous Humour levels were not statistically significantly different following oral and topical administration (p = 0.069). However, the Vitreous level of the drug after oral administration was significantly higher than that after topical administration (p < 0.001). Ocular bioavailability of ciprofloxacin in aqueous Humour following oral and topical administration is found to be similar when the drug was applied as described above. Penetration of ciprofloxacin into Vitreous Humour is less than that into aqueous Humour after topical administration.
Osman Cekic - One of the best experts on this subject based on the ideXlab platform.
-
human aqueous and Vitreous Humour levels of ciprofloxacin following oral and topical administration
Eye, 1999Co-Authors: Osman Cekic, Cosar Batman, Umit Yasar, N E Basci, A Bozkurt, S O KayaalpAbstract:Purpose To assess aqueous and Vitreous Humour ciprofloxacin concentrations following oral and topical administration of ciprofloxacin in patients with non-inflamed cornea and an intact crystalline lens, and to compare the concentrations of the drug given by either route. Methods In this prospective study, 34 patients undergoing pars plana vitrectomy for various ocular pathologies were divided into two groups. Eighteen patients received 2 drops of 0.3% ophthalmic solution of ciprofloxacin every 30 min for 3 h and then every 60 min for the next 3 h, and 16 patients received a single oral dose of 1000 mg ciprofloxacin 6 h before surgery. The aqueous and Vitreous Humour samples were simultaneously harvested after oral or topical administration during pars plana vitrectomy to assess penetration of the drug. These samples were assayed for ciprofloxacin concentrations by a method described previously by us using high-performance liquid chromatography. Results The aqueous and Vitreous Humour levels of ciprofloxacin were 0.59 ± 0.06 μg/ml (mean ± SEM) and 0.64 ± 0.06 μg/ml after oral and 0.44 ± 0.07 μg/ml and 0.22 ± 0.04 μg/ml after topical ciprofloxacin administration, respectively. Aqueous Humour levels were not statistically significantly different following oral and topical administration (p = 0.069). However, the Vitreous level of the drug after oral administration was significantly higher than that after topical administration (p<0.001). Conclusion Ocular bioavailability of ciprofloxacin in aqueous Humour following oral and topical administration is found to be similar when the drug was applied as described above. Penetration of ciprofloxacin into Vitreous Humour is less than that into aqueous Humour after topical administration.
-
Human aqueous and Vitreous Humour levels of ciprofloxacin following oral and topical administration.
Eye, 1999Co-Authors: Osman Cekic, Cosar Batman, Umit Yasar, N E Basci, A Bozkurt, Kayaalp SoAbstract:Purpose To assess aqueous and Vitreous Humour ciprofloxacin concentrations following oral and topical administration of ciprofloxacin in patients with non-inflamed cornea and an intact crystalline lens, and to compare the concentrations of the drug given by either route. Methods In this prospective study, 34 patients undergoing pars plana vitrectomy for various ocular pathologies were divided into two groups. Eighteen patients received 2 drops of 0.3% ophthalmic solution of ciprofloxacin every 30 min for 3 h and then every 60 min for the next 3 h, and 16 patients received a single oral dose of 1000 mg ciprofloxacin 6 h before surgery. The aqueous and Vitreous Humour samples were simultaneously harvested after oral or topical administration during pars plana vitrectomy to assess penetration of the drug. These samples were assayed for ciprofloxacin concentrations by a method described previously by us using high-performance liquid chromatography. Results The aqueous and Vitreous Humour levels of ciprofloxacin were 0.59 ± 0.06 μg/ml (mean ± SEM) and 0.64 ± 0.06 μg/ml after oral and 0.44 ± 0.07 μg/ml and 0.22 ± 0.04 μg/ml after topical ciprofloxacin administration, respectively. Aqueous Humour levels were not statistically significantly different following oral and topical administration (p = 0.069). However, the Vitreous level of the drug after oral administration was significantly higher than that after topical administration (p
-
Human aqueous and Vitreous Humour levels of ciprofloxacin following oral and topical administration.
Eye (London England), 1999Co-Authors: Osman Cekic, Cosar Batman, Umit Yasar, N E Basci, A Bozkurt, S O KayaalpAbstract:To assess aqueous and Vitreous Humour ciprofloxacin concentrations following oral and topical administration of ciprofloxacin in patients with non-inflamed cornea and an intact crystalline lens, and to compare the concentrations of the drug given by either route. In this prospective study, 34 patients undergoing pars plana vitrectomy for various ocular pathologies were divided into two groups. Eighteen patients received 2 drops of 0.3% ophthalmic solution of ciprofloxacin every 30 min for 3 h and then every 60 min for the next 3 h, and 16 patients received a single oral dose of 1000 mg ciprofloxacin 6 h before surgery. The aqueous and Vitreous Humour samples were simultaneously harvested after oral or topical administration during pars plana vitrectomy to assess penetration of the drug. These samples were assayed for ciprofloxacin concentrations by a method described previously by us using high-performance liquid chromatography. The aqueous and Vitreous Humour levels of ciprofloxacin were 0.59 +/- 0.06 microgram/ml (mean +/- SEM) and 0.64 +/- 0.06 microgram/ml after oral and 0.44 +/- 0.07 microgram/ml and 0.22 +/- 0.04 microgram/ml after topical ciprofloxacin administration, respectively. Aqueous Humour levels were not statistically significantly different following oral and topical administration (p = 0.069). However, the Vitreous level of the drug after oral administration was significantly higher than that after topical administration (p < 0.001). Ocular bioavailability of ciprofloxacin in aqueous Humour following oral and topical administration is found to be similar when the drug was applied as described above. Penetration of ciprofloxacin into Vitreous Humour is less than that into aqueous Humour after topical administration.
Hans Denison - One of the best experts on this subject based on the ideXlab platform.
-
Analysis of carbohydrate-deficient transferrin (CDT) in Vitreous Humour as a forensic tool for detection of alcohol misuse.
Forensic science international, 2003Co-Authors: Adam Berkowicz, Sven Wallerstedt, Kerstin Wall, Hans DenisonAbstract:Analysis of carbohydrate-deficient transferrin concentration in Vitreous Humour (VH-CDT) has recently been demonstrated to be useful for diagnosis of pre-mortal alcohol misuse, but more knowledge considering possible methodological problems is warranted. In a forensic sample we examined the stability of VH-CDT during laboratory handling as well as the possible affection of time-dependent changes of total transferrin concentrations in Vitreous Humour (VH-Transferrin) in the dead body on VH-CDT as indicator of alcohol misuse. By use of a commercial assay designed for serum analysis (CDTect) it was possible to measure VH-CDT with high precision, and detectable amounts were found in 20 of 21 alcoholics and in two of seven controls. The compound was demonstrated to be stable in Vitreous Humour during laboratory handling, since the results of the first analysis were well reproducible after 4 months storage of the specimens (rs=0.86, P=0.0002). Transferrin concentrations in Vitreous Humour (VH-Transferrin) correlated to the estimated time since the individual last time had been alive before the forensic examination (rs=0.57, P
-
analysis of carbohydrate deficient transferrin cdt in Vitreous Humour as a forensic tool for detection of alcohol misuse
Forensic Science International, 2003Co-Authors: Adam Berkowicz, Sven Wallerstedt, Kerstin Wall, Hans DenisonAbstract:Analysis of carbohydrate-deficient transferrin concentration in Vitreous Humour (VH-CDT) has recently been demonstrated to be useful for diagnosis of pre-mortal alcohol misuse, but more knowledge considering possible methodological problems is warranted. In a forensic sample we examined the stability of VH-CDT during laboratory handling as well as the possible affection of time-dependent changes of total transferrin concentrations in Vitreous Humour (VH-Transferrin) in the dead body on VH-CDT as indicator of alcohol misuse. By use of a commercial assay designed for serum analysis (CDTect™) it was possible to measure VH-CDT with high precision, and detectable amounts were found in 20 of 21 alcoholics and in two of seven controls. The compound was demonstrated to be stable in Vitreous Humour during laboratory handling, since the results of the first analysis were well reproducible after 4 months storage of the specimens (rs=0.86, P=0.0002). Transferrin concentrations in Vitreous Humour (VH-Transferrin) correlated to the estimated time since the individual last time had been alive before the forensic examination (rs=0.57, P<0.005). However, in this small sample the discriminating property of VH-CDT as indicator of alcohol misuse was not decisively affected, whether or not the variables “VH-Transferrin” and “estimated time since the individual last time had been alive” were considered in a multivariate logistic regression analysis (minor change in the β-coefficient from 0.57 to 0.52, P=0.086). We conclude that CDT is stable in Vitreous Humour during proper laboratory handling and that detection of VH-CDT is primarily a marker of alcohol misuse before death. However, the results of this study do not exclude that time-dependent changes of VH-Transferrin, possibly affecting VH-CDT, may occur in the dead body. VH-CDT analysis should thus, at present, be restricted to cases with rather short post-mortal time interval.
Federica Bortolotti - One of the best experts on this subject based on the ideXlab platform.
-
a new method for the determination of ammonium in the Vitreous Humour based on capillary electrophoresis and its preliminary application in thanatochemistry
Clinical Chemistry and Laboratory Medicine, 2019Co-Authors: Rossella Gottardo, Federica Bortolotti, Covadonga Palacio, Kseniia M Shestakova, Natalia E Moskaleva, Franco TagliaroAbstract:: Background Although the post-mortem increase of ammonium in biological fluids is well known, ammonium analysis in Vitreous Humour has never been used in recent times for the determination of the post-mortem interval. The present work represents a new application of capillary electrophoresis with indirect UV detection in the field of forensic analysis. Methods The electrophoretic separation was carried out in a running buffer made of 5 mM imidazole, 5 mM 18-crown-6 ether and 6 mM d,l-α-hydroxybutyric acid (HIBA). To overcome the lack of optical absorption of ammonium, indirect UV detection was applied. The used wavelength was 214 nm. Results The method showed good linearity in the concentration range from 0.16 to 5.0 mM. The limit of detection, 0.039 mmol/L, was established on the basis of the linearity curve. Precision and bias studies carried out on the pure ammonium solutions and in real biological samples, revealed %RSDs well below 20%. A preliminary application to real cases where the death time was precisely known (14 bodies) was carried out plotting Vitreous Humour ammonium vs. post-mortem interval with a resulting good linear correlation until 100 h post-mortem. Conclusions After validation in real cases, the present method can become a powerful tool to unravel one of the most challenging issues of forensic investigation: determination of the time of death.
-
capillary zone electrophoresis and artificial neural networks for estimation of the post mortem interval pmi using electrolytes measurements in human Vitreous Humour
International Journal of Legal Medicine, 2002Co-Authors: G Bocazbeneventi, G Manetto, Franco Tagliaro, Federica Bortolotti, Josef HavelAbstract:Determination of electrolyte concentrations (mainly potassium) in Vitreous Humour has long been considered an important tool in human death investigations for the estimation of the post-mortem interval (PMI). On the basis of its well known potential in ion analysis, capillary zone electrophoresis (CZE) has recently been applied to achieve a rapid and simultaneous determination of inorganic ions in this extracellular fluid. In the present work, artificial neural networks (ANN) were applied for modelling of the relationship of multicomponent CZE analysis of K+, NH4+, Na+, and Ba2+ ions in Vitreous Humour with PMI. In a study based on 61 cases with different causes of death and a known PMI ranging from 3 to 144 h, the use of ANNs considering all inorganic ion data from the human Vitreous Humour, achieved a substantial improvement of post-mortem interval prediction. Good linear correlation was observed (r2 = 0.98) and in comparison to the traditional linear least squares (LLS) method applied only to K+ levels in the Vitreous Humour, the prediction of PMI with ANN was improved by a factor of 5 from ≈± 15 h to less than 3 h.
-
potassium concentration differences in the Vitreous Humour from the two eyes revisited by microanalysis with capillary electrophoresis
Journal of Chromatography A, 2001Co-Authors: Franco Tagliaro, G Manetto, V L Pascali, Federica Bortolotti, Francesca Cittadini, M MarigoAbstract:This paper presents a study of the variability of potassium concentrations in the Vitreous Humour of the two eyes of the same body at identical postmortem interval. The study was carried out by collecting microsample amounts (50 μl) of Vitreous Humour and by using an original method of capillary electrophoresis with indirect detection. The electrophoretic separations were carried out in a pH 4.5 running buffer composed of 5 mmol/l imidazole, 5 mmol/l 18-crown-6 ether and 6 mmol/l α-hydroxybutyric acid. Detection was by indirect UV absorption at 214 nm. Vitreous Humour samples were collected from 57 medico–legal autopsies or external examinations of cases of sudden natural or violent deaths. All samples prior to analysis were diluted 1:20 with a 40 μg/ml aqueous solution of barium, the used internal standard, and finally injected by nitrogen pressure. The mean concentrations of potassium measured in the two eyes of all the cases included in the present study ranged from 4.1 to 23.5 mmol/l with the postmortem interval values varying from 7 to 144 h. A highly significant (P<0.0001) linear correlation was found between these two parameters as described by the equation: y=0.1698x+2.3587, r=0.89. The intra-eye variability of potassium concentrations was low with an average RSD of 3.89% (±1.83 SD) (48 eyes, five samples per eye). No statistically significant difference was found between the potassium concentrations in the two eyes of the same subject in a group of 24 cases, excepting a single case.
-
capillary zone electrophoresis of potassium in human Vitreous Humour validation of a new method
Journal of Chromatography B: Biomedical Sciences and Applications, 1999Co-Authors: Franco Tagliaro, G Manetto, Federica Bortolotti, Francesca Cittadini, Daniela Marchetti, M MarigoAbstract:: The analysis of potassium in the Vitreous Humour has long been regarded as an important tool in medicolegal and forensic toxicological investigation, particularly for the determination of the post-mortem interval. The present work was aimed at the optimisation and validation of a reliable, simple and fast capillary electrophoresis method for potassium analysis in the human Vitreous Humour with indirect UV detection at a wavelength of 214 nm. Electrophoretic separations were carried out in a running buffer comprising 5 mM imidazole, 5 mM 18-crown-6 ether and 6 mM D,L alpha-hydroxybutyric acid (HIBA), adjusted to pH 4.5. Constant voltage runs were carried out by applying a voltage of 500 V/cm at 25 degrees C. The samples were injected in the hydrodynamic mode at the anodic end of the capillary (0.5 p.s.i. for 10 s; 1 p.s.i. = 6894.76 Pa). The method showed good linearity in the concentration range from 6.5 mM to 16.25 microM, with an r2 value of 0.9994. The limit of detection, based on a signal-to-noise ratio of three, was 9.0 microM. Absolute intra-day RSDs of migration times were <0.40%, while the day-to-day values were < or =1.72%. Absolute peak area reproducibility was always better than 2.50%. A comparison of capillary electrophoresis with flame photometry on twelve real autopsy samples showed an excellent correlation with an r2 value of 0.9333. A preliminary application to real cases (20 subjects) was carried out plotting Vitreous Humour potassium vs. post-mortem interval with a resulting r2 of 0.904 and a Y-intercept of 4.75 mM, in agreement with the existing literature.
