Studies on Orchidaceae Alkaloids XL. Biosynthetic studies of (-)-Cryptostyline I

Agurell S, I. Granelli, Leander K, Rosenblom J
1974 | 28(10) (1175-9)

Studies on Orchidaceae Alkaloids XXXVI. Alkaloids from some Vanda and Vandopsis Species

Brandänge S, , I. Granelli
1973 | 27(3) (1096-7)

Studies on Orchidaceae Alkaloids XVIII. Isolation of Phalaenopsin La from Kingiella taenialis(Lindl.) Rolfe

Brandänge S, I. Granelli, Luning B
1970 | 24(1)

Determination of metoprolol enantiomers in human plasma and saliva samples utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry

Hatem Elmongy; Mohamed Abdel-Rehim
1970 | Biomed. Chromatogr.

Determination of metoprolol enantiomers in human plasma and saliva samples utilizing microextraction by packed sorbent and liquid chromatography–tandem mass spectrometry

Hatem Elmongy, Hytham Ahmed, Abdel-Aziz Wahbi, Ahmad Amini, Anders Colmsjö and Mohamed Abdel-Rehim
1970 | Biomed. Chromatogr. | 30 (8) (1309-1317)

Saliva as an alternative specimen to plasma for drug bioanalysis: A review

Hatem Elmongy and Mohamed Abdel-Rehim
1970 | Trends Analyt Chem | 83 (B) (70-79)

Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: I. Determination of methadone in human plasma utilizing liquid chromatographyetandem mass spectrometry

Aziza El-Beqqali and Mohamed Abdel-Rehim
1970 | Anal. Chim. Acta | 936 (116-122)

Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: I. Determination of methadone in human plasma utilizing liquid chromatographyetandem mass spectrometry

Aziza El-Beqqali, Mohamed Abdel-Rehim*
1970 | Anal. Chim. Acta | 936 (116-122)

In the present work molecularly imprinted sol-gel tablet (MIP-Tablet) was prepared. The MIP-sol-gel was prepared as a thin layer on polyethylene material in a tablet form. Methadone-d9 was selected as the template and 3-(propylmethacrylate)-trimethoxysilane was used as precursor. MIP-Tablet was applied for micro-solid phase extraction (μ-SPE). The MIP-Tablet was used for the determination of methadone in human plasma samples utilizing liquid chromatography-tandem mass spectrometry; and each tablet could be used twenty times. The extraction time was 10 min while desorption time was 6 min. Factors affecting the extraction efficiency such as desorption solvents, sample pH, salt addition, extraction time, desorption time and adsorption capacity were investigated. The calibration curves were obtained within the range of 5–5000 ng/mL using methadone in human plasma samples. The coefficients of determination (r2) values were ≥0.999 for all runs and the extraction recovery was >80%. The accuracy values for quality control samples varied from +3.6 to +9.7% and the inter-day precision (RSD %) values were ranged from 5.0 to 8.0%. The limit of detection was 1.0 ng/mL and the lower limit of quantification was 5 ng/mL utilizing methadone in human plasma samples.

Saliva as an alternative specimen to plasma for drug bioanalysis. A review

Hatem Elmongy, Mohamed Abdel-Rehim*
1970 | Trends Analyt Chem | 83 (70-79)

Saliva provides a suitable medium for screening and determination of drugs. It is easy to collect and handle besides the non-invasive sampling. Extraction techniques such as micro extraction by packed sorbent (MEPS) and dried saliva spot (DSS) provides fast and efficient recovery of the analytes. Moreover, MEPS could be fully automated to ascertain method reproducibility and DSS provides fast simultaneous collection
and extraction of samples. Several studieswere conducted to determine drugs in saliva in correlation to plasma aiming to establish rigid evidence on the suitability of saliva in monitoring of drug levels. Only free drug could be present in salivary fluid thus protein binding of drugs affect markedly on the salivary levels of drugs. Pharmacokinetic parameters could be determined for drugs in saliva with emphasis on diffusion parameters of drugs to salivary fluid such as pH and drug lipophilicity. Screening techniques are mainly based on mass spectrometry (MS) with an emphasis on Liquid Chromatography-Mass Spectrometry (LC-MS), due to limited sample volumes and the low detection limits. Saliva could make drug testing outside laboratory environments feasible with the appropriate techniques for analysis. This review focuses on the developments and challenges in testing of drugs in saliva in correlation to plasma and application to drug analysis in saliva regarding therapeutic drug monitoring and pharmacokinetics.

Perfluoroalkyl acids and their precursors in Swedish food: The relativeimportance of direct and indirect dietary exposure

Gebbink, W.A.; Glynn, A.; Darnerud, P.O.; Berger, U.
1970 | Environ. Pollut. | 198 (108-115)

We analyzed food market basket samples obtained in Sweden from 1999, 2005, and 2010 for perfluoroalkyl acids (PFAAs) and a range of precursor compounds. Perfluorooctane sulfonic acid (PFOS) precursors were detected in all food year pools with the highest concentrations in 1999. Six polyfluoroalkyl phosphate diesters (diPAPs, 4:2/6:2, 6:2/6:2, 6:2/8:2, 8:2/8:2, 6:2/10:2, and 10:2/10:2) were detected in the year pools with the highest PdiPAP concentrations in 1999 and 2005. All precursors were predominantly found in meat, fish, and/or eggs based on analysis of individual food groups from 1999. Based on year pools, PFOS precursors contributed between 4 and 1% as an indirect source to total
dietary PFOS intakes between 1999 and 2010. Perfluorohexanoic acid (PFHxA) exposure originated entirely from diPAPs, whereas for perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA), diPAPs contributed between 1 and 19% to total exposure. The lowest precursor contributions were generally seen in food samples from 2010.

Temporal changes (1997-2012) of perfluoroalkyl acids and selected precursors (including isomers) in Swedish human serum

Gebbink, W.A.; Glynn, A.; Berger, U.
1970 | Environ. Pollut. | 199 (166-173)

Concentrations (including isomer patterns) and temporal changes (1997e2012) of perfluoroalkyl acids (PFAAs) and selected perfluorooctane sulfonate (PFOS) and perfluoroalkyl carboxylic acid (PFCA) precursors were determined in serum samples from Swedish women. Perfluorooctane sulfonamide (FOSA) and perfluorooctane sulfonamidoacetic acid (FOSAA), as well as its N-methyl and N-ethyl derivatives (MeFOSAA and EtFOSAA) were consistently detected. Highest PFOS precursor concentrations were found for EtFOSAA (before year 2000) or MeFOSAA and FOSAA (after 2000). Disappearance half-lives for all PFOS precursors were shorter compared to PFOS. 4:2/6:2 and 6:2/6:2 polyfluoroalkyl phosphate diesters (diPAPs) were detected in <60% of the samples, whereas 6:2/8:2 and 8:2/8:2 diPAPs were detected in >60% of the samples, but showed no significant change in concentrations over time. Linear and sumbranched isomers were quantified separately for three PFAAs and three precursors. Significant changes between 1997 and 2012 in the % linear isomer were observed for PFOA and FOSA (increase) and PFOS (decrease).

Compositional Effects on Leaching of Stain-Guarded (perfluoroalkyl 2 and Polyfluoroalkyl Substance-Treated) Carpet in Landfill Leachate

Minhee Kim; Loretta Y. Li; John R. Grace; Jonathan P. Benskin; and Michael G. Ikonomou;
1970 | Environ. Sci. Technol.

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