Laboratory practice of organic acid analysis based on gas chromatography–mass spectrometry in China

2021 ◽  
Vol 45 (4-5) ◽  
pp. 229-235
Author(s):  
Lizi Jin ◽  
Tianjiao Zhang ◽  
Jie Zeng ◽  
Chuanbao Zhang
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Acid ◽  
Internal Standard ◽  
Turnaround Time ◽  
Gas Chromatography Mass Spectrometry ◽  
Reference Ranges ◽  
Laboratory Practice ◽  
Chromatography Mass Spectrometry ◽  
Quantitative Results

Abstract Objectives The aim of this study is to investigate the status of laboratory practice of organic acid (OA) analysis using gas chromatography–mass spectrometry in China. Methods A survey, investigating details of laboratory practice of OA analysis, was issued on the website of the National Center for Clinical Laboratories of China. Nationwide external quality assessment participating laboratories of OA assay were informed to participate in this survey. Results A total of 36 laboratories completed this survey. Most laboratories started OA analysis during 2016–2020. Most (100%) labs reported semi-quantitative results, in which 79.4% of labs adopted the form of the ratio of peak area of OA and quantitative internal standard. Rare labs reported quantitative results. Few labs released reports in three days, most in 5–7 days. The source of control materials varied, 64.5% of labs adapted self-made materials. A total of 43.8% of laboratories directly used reference intervals (RIs) from published literature, 43.8% of laboratories established RIs themselves, but 21.2% of laboratories reported they didn’t verify RIs. Conclusions Appropriate supervision for the organic acid assay is needed in the aspect of the turnaround time of reporting results, the establishment validation and verification of reference ranges, and the quantification of results.

Specific estimation of 24,25-dihydroxyvitamin D in plasma by gas chromatography-mass spectrometry.

1984 ◽  
Vol 30 (7) ◽  
pp. 1193-1198 ◽  
Author(s):  
R D Coldwell ◽  
D J Trafford ◽  
H L Makin ◽  
M J Varley ◽  
D N Kirk
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Plasma Vitamin ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D3 ◽  
Dihydroxyvitamin D ◽  
Chromatography Mass Spectrometry ◽  
24,25 Dihydroxyvitamin D3

Abstract This paper describes a specific mass-fragmentographic method, involving a stable-isotope-labeled internal standard, for measurement of 24,25-dihydroxyvitamin D in human plasma. Vitamin D metabolites were rapidly extracted from plasma by using Sep-Pak C18 cartridges and separated into fractions on Sep-Pak SIL cartridges. The polar fraction, containing the dihydroxylated metabolites, was further purified by "high-performance" liquid chromatography on Zorbax SIL. The fraction containing 24,25-dihydroxyvitamin D was collected, evaporated, and converted to the 24:25-cyclic n-butyl boronate-3-trimethylsilyl ether derivative before analysis by gas chromatography-mass spectrometry. The intensity of the mass fragment (m/z 449, m/z 455 for the hexadeuterated internal standard) arising from the loss of one of the angular methyls and the 3-silanol group [( M-90-15]+) was monitored. The minimum limit of detection for this method is about 0.1 microgram/L. Inter- and intra-assay reproducibility was acceptable, and analytical recovery of added 24,25-dihydroxyvitamin D3 over the concentration range 1.0 to 5.0 micrograms/L was quantitative. Concentrations of 24,25-dihydroxyvitamin D3 in plasma of 21 apparently healthy volunteers were between 0.55 and 5.39 micrograms/L, higher values being obtained after prolonged exposure to the sun. No 24,25-dihydroxyvitamin D2 could be detected in any plasma sample examined.

Determination of Pyrantel in Swine Liver by Flame Ionization Gas Chromatography and Confirmation by Gas Chromatography /Mass Spectrometry

1990 ◽  
Vol 73 (6) ◽  
pp. 883-886
Author(s):  
Susan S.C Tai ◽  
Nancy Cargile ◽  
Charlie J Barnes ◽  
Philip Kijak
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Tissue Samples ◽  
Flame Ionization ◽  
Chromatography Mass Spectrometry ◽  
Ionization Method ◽  
Swine Liver

Abstract During an evaluation of the gas chromatography/mass spectrometry (GC/MS) confirmatory procedure of Lynch and Bartoluccl for pyrantel residues in swine tissues, we developed a GC flame Ionization method for quantltatlng pyrantel residues In extracts of swine liver. The method was subjected to trial principally In the laboratories of Biospherics, Inc., using control liver, fortified control liver, and Incurred liver tissue samples. Although the method does not meet all of the current Food and Drug Administration criteria, it compares favorably to the official determinative method. Portions of the same extract can be used for quantitation and for GC/MS confirmation, true recoveries appear to be slightly higher, and an internal standard Is not required. The precision of this method equals or exceeds that of the official determinative method.

Quantification of 5 alpha- and 5 beta-androstanediols in urine by gas chromatography-mass spectrometry.

1987 ◽  
Vol 33 (2) ◽  
pp. 256-260 ◽  
Author(s):  
L Muller ◽  
G Phillipou
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Diurnal Rhythm ◽  
Capillary Gas Chromatography ◽  
Internal Standard ◽  
Reference Intervals ◽  
Gas Chromatography Mass Spectrometry ◽  
Positive Bias ◽  
Men And Women ◽  
Chromatography Mass Spectrometry

Abstract We measured concentrations of 5 alpha-androstane-3 alpha,17 beta-diol (Ad) and 5 beta-androstane-3 alpha,17 beta-diol (beta-Ad) in urine by specific capillary gas chromatography-mass spectrometry, with [16,16,17 alpha-2H3]-5 alpha-androstane-3 alpha,17 beta-diol as the internal standard. Comparison of the so-derived reference intervals for Ad and beta-Ad in men and women with those previously published indicates a significant positive bias for many of the previous assays in comparison with our procedure. Both Ad and beta-Ad have a pronounced diurnal rhythm, with maximum excretion in the interval 2300-0700 hours. Concentrations of Ad and beta-Ad were significantly correlated (r = 0.786, p less than 0.001), but the ratio of Ad to beta-Ad was not correlated to that for androsterone to etiocholanolone, the major 5 alpha and 5 beta metabolites of androgens in urine.

Postmortem Analysis of Benzodiazepines in Human Bone by Gas Chromatography–Mass Spectrometry

2020 ◽  
Author(s):  
Rosanna Mancini ◽  
Lucia Fernadez-Lopez ◽  
Maria Falcon ◽  
Manuela Pellegrini ◽  
Aurelio Luna ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Fused Silica ◽  
Process Efficiency ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry ◽  
Fused Silica Capillary ◽  
Silica Capillary Column

Abstract A procedure based on gas chromatography-mass spectrometry was developed for the analysis of benzodiazepines (nordiazepam, oxazepam, lormetazepam, lorazepam, clonazepam, bromazepam and alprazolam) in postmortem human ribs. Powdered bone samples, including marrow remains inside, with the internal standard diazepam-d5 were subjected to enzymatic hydrolysis with 100 μL of β-glucoronidase and were incubated in sodium hydroxide for 1 h in a 70°C oven. Samples underwent liquid phase extraction and ethyl acetate was used as eluent. Chromatography was performed on a fused silica capillary column and the selected-ion-monitoring mode was used for analytes determination. The method was validated in the range 0.1–0.5 ng/mg (depending on the benzodiazepine) to 100 ng/mg with average values of recovery, matrix effect and process efficiency ranged from 83.2 to 94.3%, from 97.3 to 102.1% and from 80.5 to 91.2%, respectively. The intra- and inter-day accuracy was <15%. The procedure was tested in rib specimens obtained during routine autopsies from 20 cases where these benzodiazepines were found in blood. Benzodiazepines were detected in the combined bone and marrow samples in 60% of cases. Lorazepam was detected in bone in the range of 0.3–0.7 ng/mg, nordiazepam at 1.3–4.2 ng/mg and oxazepam at 1.1–1.2 ng/mg. To our knowledge, this protocol for the simultaneous analysis of these benzodiazepines is the first performed and validated using human ribs.

scholarly journals Development of Sensitive and Specific Analysis of Vildagliptin in Pharmaceutical Formulation by Gas Chromatography-Mass Spectrometry

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Ebru Uçaktürk
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Pharmaceutical Formulation ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry ◽  
Validation Parameters ◽  
Diagnostic Ions

A sensitive and selective gas chromatography-mass spectrometry (GC-MS) method was developed and fully validated for the determination of vildagliptin (VIL) in pharmaceutical formulation. Prior to GC-MS analysis, VIL was efficiently derivatized with MSTFA/NH4I/β-mercaptoethanol at 60°C for 30 min. The obtained O-TMS derivative of VIL was detected by selected ion monitoring mode using the diagnostic ionsm/z223 and 252. Nandrolone was chosen as internal standard. The GC-MS method was fully validated by the following validation parameters: limit of detection (LOD) and quantitation (LOQ), linearity, precision, accuracy, specificity, stability, robustness, and ruggedness. LOD and LOQ were found to be 1.5 and 3.5 ng mL−1, respectively. The GC-MS method is linear in the range of 3.5–300 ng mL−1. The intra- and interday precision values were less than ≤3.62%. The intra- and interday accuracy values were found in the range of-0.26–2.06%. Finally, the GC-MS method was successfully applied to determine VIL in pharmaceutical formulation.

Determination of Clenbuterol in Cattle, Sheep, and Swine Tissues by Electron Ionization Gas Chromatography/Mass Spectrometry

1994 ◽  
Vol 77 (4) ◽  
pp. 917-924 ◽  
Author(s):  
Roger T Wilson ◽  
Joseph M Groneck ◽  
Kathleen P Holland ◽  
A Carolyn Henry
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Electron Ionization ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Method Performance ◽  
Chromatography Mass Spectrometry ◽  
Coefficients Of Variation

Abstract A gas chromatographic/mass spectrometric procedure is described for the quantitation and confirmation of clenbuterol residues from cattle, sheep, and swine tissues. After liquid–liquid extraction and derivatization with phosgene in an aqueous pH 10.1 buffer, the cyclic oxazolidone derivative is quantitated with a clenbuterol analogue as internal standard (NAB-760 CI). Confirmation is accomplished by comparison of ion ratios with those of a pure synthesized standard of clenbuterol oxazolidin-3-one obtained by selected ion monitoring, electron ionization gas chromatography/mass spectrometry on a benchtop instrument. Statistical information based on a series of standard curves for fortified tissues is included to describe method performance. Ion ratio variations were under 15%, and coefficients of variation for spiked tissue standard curves were above 0.997. Recoveries averaged 87.1 ± 6.6% for liver tissues across all 3 species and 67.1 ± 3.8% for muscle tissue across all 3 species.

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