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Vol 2 Iss 3 by Khaled Mohamed

Research paper thumbnail of Fatal Intoxications with Para-Phenylenediamine in Upper Egypt

Para-phenylenediamine (PPD) is used alone or in combination with Henna as hair dye or skin decora... more Para-phenylenediamine (PPD) is used alone or in combination with Henna as hair dye or skin decoration. A five year retrospective study from 2007 to December 2012 was conducted at Assiut Forensic Chemistry Laboratory of Medic-legal Department, Assiut, to understand the magnitude and pattern of accidental, suicidal and homicide poisoning by PPD among males and females in Upper Egypt. During this period, a total of 84 poisoning cases are reported. The suicidal, homicidal and accidental cases were (91.7%), (7.1%) and (1.2%), respectively. The suicidal poisoning of females was higher (67.9%) than of males (32.1%). Most of the PPD deaths were between the third and fourth decades of life. PPD is detected by HPLC-DAD in stomach contents, blood, liver and urine samples. The cases are reported with the advice "public education and strict control over the sale and distribution of PPD should be done to reduce poisoning by this agent.
KeyWords: Paraphenylenediamine; Acute poisoning; Detection; HPLC-DAD.

Papers by Khaled Mohamed

Research paper thumbnail of A Gas Chromatography-Triple Quadrupole Mass Spectrometry Assay for the Quantification of Opiates in Human Blood Samples

Journal of analytical toxicology, Jan 6, 2018

A simplified protein precipitation method in combination with gas chromatography-triple quadrupol... more A simplified protein precipitation method in combination with gas chromatography-triple quadrupole mass spectrometry (GC-MS-MS) analysis was developed and validated for the simultaneous determination of codeine, morphine, 6-acetylmorphine (6-MAM), hydrocodone and hydromorphone in human blood samples. A protein precipitation with 10% trichloroacetic acid followed by solid-phase extraction using a mixed-mode cartridge was used to separate the analyte from the blood samples. A BSTFA + 1% TMCS was used for derivatization of opiates prior to the analysis. Codeine-D3, morphine-D3, 6-acetylmorphine-D3 and hydrocodone-D6 were used as internal standards. The GC-MS-MS was operated under multiple-reaction monitoring mode using electron ionization technique. The transition ions used for quantitation were 371 → 234 for codeine, 429 → 146 for morphine, 399 → 287 for 6-MAM, 299 → 228 for hydrocodone and 357 → 314 for hydromorphone. The method was linear over the concentration range 2.5-1000 ng/mL ...

Research paper thumbnail of Comparison of 3 Derivatization Methods for the Analysis of Amphetamine-Related Drugs in Oral Fluid by Gas Chromatography-Mass Spectrometry

Analytical Chemistry Insights

The heptafluorobutyric anhydride (HFBA), pentafluoropropionic anhydride (PFPA), and trifluoroacet... more The heptafluorobutyric anhydride (HFBA), pentafluoropropionic anhydride (PFPA), and trifluoroacetic anhydride (TFAA) are compared as derivatizing reagents to use as the optimal method for the analysis of 10 amphetamines and cathinones in oral fluid. The target compounds were amphetamine (AMP), methamphetamine (MA), 4-methylamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), cathinone (CAT), methcathinone, mephedrone, and ephedrine

Research paper thumbnail of Application of a LC-MS/MS method developed for the determination ofp-phenylenediamine,N-acetyl-p-phenylenediamine andN,N-diacetyl-p-phenylenediamine in human urine specimens

Biomedical Chromatography, 2016

Cases of poisoning by p-phenylenediamine (PPD) are detected sporadically. Recently an article on ... more Cases of poisoning by p-phenylenediamine (PPD) are detected sporadically. Recently an article on the development and validation of an LC-MS/MS method for the detection of PPD and its metabolites, N-acetyl-p-phenylenediamine (MAPPD) and N,N-diacetyl-p-phenylenediamine (DAPPD) in blood was published. In the current study this method for detection of these compounds was validated and applied to urine samples. The analytes were extracted from urine samples with methylene chloride and ammonium hydroxide as alkaline medium. Detection was performed by LC-MS/MS using electrospray positive ionization under multiple reaction-monitoring mode. Calibration curves were linear in the range 5-2000 ng/mL for all analytes. Intra- and inter-assay imprecisions were within 1.58-9.52 and 5.43-9.45%, respectively, for PPD, MAPPD and DAPPD. Inter-assay accuracies were within -7.43 and 7.36 for all compounds. The lower limit of quantification was 5 ng/mL for all analytes. The method, which complies with the validation criteria, was successfully applied to the analysis of PPD, MAPPD and DAPPD in human urine samples collected from clinical and postmortem cases.

Research paper thumbnail of A study of acute poisoning by p-phenylenediamine (hair dye) used orally in Upper Egypt

Research paper thumbnail of GC-MS Method for Quantification of Mephedrone in Human Blood Sample

Journal of chromatographic science, Jan 18, 2017

Abuse of mephedrone (4-methylmethcathinone) has emerged among the last few years. Intoxication an... more Abuse of mephedrone (4-methylmethcathinone) has emerged among the last few years. Intoxication and fatality associated with mephedrone have been reported in the literature. The present work describes a simple and rapid gas chromatography-mass spectrometry (GC-MS) method for detection and quantification of mephedrone in human blood samples using GC-MS. Blood was deproteinated with acetonitrile and the supernatant was derivatized and extracted in a single step with ethyl chloroformate and ethyl acetate. Methamphetamine-d5 was used as an internal standard (IS). The characteristic ions at m/z 58, 119 and 130 for mephedrone and m/z 62, 92 and 134 for methamphetamine-D5 were used for quantification of the analyte. The calibration curve was linear within the concentration range 10-2,000 ng/mL. Intra- and inter-assay precisions (%RSD) were within 10.9-11.9 and 9.2-11.2, respectively. Intra-assay accuracy (%Bias) was between 1.8 and 2.8. The method was successfully applied to detect and quan...

Research paper thumbnail of Fatal Intoxications with Para-Phenylenediamine in Upper Egypt

Para-phenylenediamine (PPD) is used alone or in combination with Henna as hair dye or skin decora... more Para-phenylenediamine (PPD) is used alone or in combination with Henna as hair dye or skin decoration. A five year retrospective study from 2007 to December 2012 was conducted at Assiut Forensic Chemistry Laboratory of Medic-legal Department, Assiut, to understand the magnitude and pattern of accidental, suicidal and homicide poisoning by PPD among males and females in Upper Egypt. During this period, a total of 84 poisoning cases are reported. The suicidal, homicidal and accidental cases were (91.7%), (7.1%) and (1.2%), respectively. The suicidal poisoning of females was higher (67.9%) than of males (32.1%). Most of the PPD deaths were between the third and fourth decades of life. PPD is detected by HPLC-DAD in stomach contents, blood, liver and urine samples. The cases are reported with the advice "public education and strict control over the sale and distribution of PPD should be done to reduce poisoning by this agent.
KeyWords: Paraphenylenediamine; Acute poisoning; Detection; HPLC-DAD.

Research paper thumbnail of A Gas Chromatography-Triple Quadrupole Mass Spectrometry Assay for the Quantification of Opiates in Human Blood Samples

Journal of analytical toxicology, Jan 6, 2018

A simplified protein precipitation method in combination with gas chromatography-triple quadrupol... more A simplified protein precipitation method in combination with gas chromatography-triple quadrupole mass spectrometry (GC-MS-MS) analysis was developed and validated for the simultaneous determination of codeine, morphine, 6-acetylmorphine (6-MAM), hydrocodone and hydromorphone in human blood samples. A protein precipitation with 10% trichloroacetic acid followed by solid-phase extraction using a mixed-mode cartridge was used to separate the analyte from the blood samples. A BSTFA + 1% TMCS was used for derivatization of opiates prior to the analysis. Codeine-D3, morphine-D3, 6-acetylmorphine-D3 and hydrocodone-D6 were used as internal standards. The GC-MS-MS was operated under multiple-reaction monitoring mode using electron ionization technique. The transition ions used for quantitation were 371 → 234 for codeine, 429 → 146 for morphine, 399 → 287 for 6-MAM, 299 → 228 for hydrocodone and 357 → 314 for hydromorphone. The method was linear over the concentration range 2.5-1000 ng/mL ...

Research paper thumbnail of Comparison of 3 Derivatization Methods for the Analysis of Amphetamine-Related Drugs in Oral Fluid by Gas Chromatography-Mass Spectrometry

Analytical Chemistry Insights

The heptafluorobutyric anhydride (HFBA), pentafluoropropionic anhydride (PFPA), and trifluoroacet... more The heptafluorobutyric anhydride (HFBA), pentafluoropropionic anhydride (PFPA), and trifluoroacetic anhydride (TFAA) are compared as derivatizing reagents to use as the optimal method for the analysis of 10 amphetamines and cathinones in oral fluid. The target compounds were amphetamine (AMP), methamphetamine (MA), 4-methylamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), cathinone (CAT), methcathinone, mephedrone, and ephedrine

Research paper thumbnail of Application of a LC-MS/MS method developed for the determination ofp-phenylenediamine,N-acetyl-p-phenylenediamine andN,N-diacetyl-p-phenylenediamine in human urine specimens

Biomedical Chromatography, 2016

Cases of poisoning by p-phenylenediamine (PPD) are detected sporadically. Recently an article on ... more Cases of poisoning by p-phenylenediamine (PPD) are detected sporadically. Recently an article on the development and validation of an LC-MS/MS method for the detection of PPD and its metabolites, N-acetyl-p-phenylenediamine (MAPPD) and N,N-diacetyl-p-phenylenediamine (DAPPD) in blood was published. In the current study this method for detection of these compounds was validated and applied to urine samples. The analytes were extracted from urine samples with methylene chloride and ammonium hydroxide as alkaline medium. Detection was performed by LC-MS/MS using electrospray positive ionization under multiple reaction-monitoring mode. Calibration curves were linear in the range 5-2000 ng/mL for all analytes. Intra- and inter-assay imprecisions were within 1.58-9.52 and 5.43-9.45%, respectively, for PPD, MAPPD and DAPPD. Inter-assay accuracies were within -7.43 and 7.36 for all compounds. The lower limit of quantification was 5 ng/mL for all analytes. The method, which complies with the validation criteria, was successfully applied to the analysis of PPD, MAPPD and DAPPD in human urine samples collected from clinical and postmortem cases.

Research paper thumbnail of A study of acute poisoning by p-phenylenediamine (hair dye) used orally in Upper Egypt

Research paper thumbnail of GC-MS Method for Quantification of Mephedrone in Human Blood Sample

Journal of chromatographic science, Jan 18, 2017

Abuse of mephedrone (4-methylmethcathinone) has emerged among the last few years. Intoxication an... more Abuse of mephedrone (4-methylmethcathinone) has emerged among the last few years. Intoxication and fatality associated with mephedrone have been reported in the literature. The present work describes a simple and rapid gas chromatography-mass spectrometry (GC-MS) method for detection and quantification of mephedrone in human blood samples using GC-MS. Blood was deproteinated with acetonitrile and the supernatant was derivatized and extracted in a single step with ethyl chloroformate and ethyl acetate. Methamphetamine-d5 was used as an internal standard (IS). The characteristic ions at m/z 58, 119 and 130 for mephedrone and m/z 62, 92 and 134 for methamphetamine-D5 were used for quantification of the analyte. The calibration curve was linear within the concentration range 10-2,000 ng/mL. Intra- and inter-assay precisions (%RSD) were within 10.9-11.9 and 9.2-11.2, respectively. Intra-assay accuracy (%Bias) was between 1.8 and 2.8. The method was successfully applied to detect and quan...