Urine metabolome analysis by gas chromatography–mass spectrometry (GC–MS): Standardization and optimization of protocols for urea removal and short-term sample storage

2018 ◽  
Vol 485 ◽  
pp. 236-242 ◽  
Author(s):  
Francesco Palmas ◽  
Michele Mussap ◽  
Claudia Fattuoni
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Gas Chromatography Mass Spectrometry ◽  
Sample Storage ◽  
Metabolome Analysis ◽  
Short Term ◽  
Chromatography Mass Spectrometry ◽  
Urine Metabolome

scholarly journals Evaluating Phthalate Contaminant Migration Using Thermal Desorption–Gas Chromatography–Mass Spectrometry (TD–GC–MS)

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 683 ◽  
Author(s):  
Yukihiro Ouchi ◽  
Hiroyuki Yanagisawa ◽  
Shigehiko Fujimaki
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Thermal Desorption ◽  
Gas Chromatography Mass Spectrometry ◽  
Approximation Model ◽  
Contaminant Migration ◽  
Short Term ◽  
Small Organic Molecules ◽  
Chromatography Mass Spectrometry ◽  
Ethylhexyl Phthalate

This study describes a methodology for evaluating regulatory levels of phthalate contamination. By collecting experimental data on short-term phthalate migration using thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS), the migration of di(2-ethylhexyl) phthalate (DEHP) from polyvinyl chloride (PVC) to polyethylene (PE) was found to be expressed by the Fickian approximation model, which was originally proposed for solid (PVC)/liquid (solvent) migration of phthalates. Consequently, good data correlation was obtained using the Fickian approximation model with a diffusion coefficient of 4.2 × 10−12 cm2/s for solid (PVC)/ solid (PE) migration of DEHP at 25 °C. Results showed that temporary contact with plasticized polymers under a normal, foreseeable condition may not pose an immediate risk of being contaminated by phthalates at regulatory levels. However, as phthalates are small organic molecules designed to be dispersed in a variety of polymers as plasticizers at a high compounding ratio, the risk of migration-related contamination can be high in comparison with other additives, especially under high temperatures. With these considerations in mind, the methodology for examining regulatory levels of phthalate contamination using TD–GC–MS has been successfully demonstrated from the viewpoint of its applicability to solid (PVC)/solid (PE) migration of phthalates.

Diagnosis of gastroenterological diseases by metabolome analysis using gas chromatography–mass spectrometry

2011 ◽  
Vol 47 (1) ◽  
pp. 9-20 ◽  
Author(s):  
Masaru Yoshida ◽  
Naoya Hatano ◽  
Shin Nishiumi ◽  
Yasuhiro Irino ◽  
Yoshihiro Izumi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Gas Chromatography Mass Spectrometry ◽  
Metabolome Analysis ◽  
Chromatography Mass Spectrometry

scholarly journals A New Method for Workplace Monitoring of Airborne Diacetyl and 2,3-Pentanedione Using Thermal Desorption Tubes and Gas Chromatography-Mass Spectrometry

2019 ◽  
Vol 63 (4) ◽  
pp. 407-414
Author(s):  
Ian Pengelly ◽  
Veronica M Brown
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Thermal Desorption ◽  
Passive Sampling ◽  
New Method ◽  
Gas Chromatography Mass Spectrometry ◽  
Short Term ◽  
Chromatography Mass Spectrometry ◽  
Exposure Limit ◽  
Workplace Monitoring

Abstract Diacetyl is a potentially harmful chemical that is used as an artificial flavouring in the food industry and may also be generated during processing of some natural products including coffee. In Europe, an 8-h time weighted average occupational exposure limit (TWA-OEL) of 20 ppb has been adopted for diacetyl, together with a short-term exposure limit (STEL) of 100 ppb. A sensitive new measurement method for diacetyl, and the related compound 2,3-pentanedione has been developed and evaluated. The new method uses Tenax TA sorbent tubes as the sampling media with analysis by thermal desorption (TD) and gas chromatography-mass spectrometry (GC-MS). The sample tubes are suitable for both active (pumped) and passive (diffusive) sampling. Diacetyl is stable on the sample tubes for at least 3 months but 2,3-pentanedione requires analysis within a month. Sample recovery is unaffected by changes in relative humidity and the presence of acetic acid. For short-term sampling, active sampling is recommended. The safe sampling volume for diacetyl is 3 litres which, at a flow rate of 100 ml min−1, equates to a maximum recommended sampling time of 30 min. For long-term samples, in particular collection of personal samples, passive sampling is recommended. Diffusive uptake rates have been determined for both diacetyl and 2,3-pentanedione on Tenax TA tubes fitted with standard diffusion heads over sampling periods of 1 to 8 h. Analytical limits of detection are approximately 0.2 ng for diacetyl and 0.1 ng for 2,3-pentanedione. These values equate to airborne concentrations of around 0.04 ppb of diacetyl and 0.02 ppb of 2,3-pentanedione for a 1.5-litre active sample and 0.3 ppb of diacetyl and 0.1 ppb of 2,3-pentanedione for an 8-h passive sample. In the case of passive sampling, this limit of detection is less than 1/50th of the new European TWA-OEL for diacetyl of 20 ppb. The method can also be used to identify the presence of other volatile organic compounds at sub-ppm concentrations.

Late diagnosis of 3β-Hydroxysteroid dehydrogenase deficiency: the pivotal role of gas chromatography-mass spectrometry urinary steroid metabolome analysis and a novel homozygous nonsense mutation in the HSD3B2 gene

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Pavlos Fanis ◽  
Vassos Neocleous ◽  
Konstantina Kosta ◽  
Aristea Karipiadou ◽  
Michaela F. Hartmann ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Nonsense Mutation ◽  
Hydroxysteroid Dehydrogenase ◽  
Gas Chromatography Mass Spectrometry ◽  
Team Approach ◽  
Metabolome Analysis ◽  
Rare Type ◽  
Chromatography Mass Spectrometry ◽  
Urinary Steroid

AbstractObjectives3β-Hydroxysteroid dehydrogenase (3β-HSD) deficiency is a rare type of congenital adrenal hyperplasia caused by recessive loss-of-function mutations in HSD3B2 gene.Case presentationWe report an 8.5-year-old, 46XY, Roma boy with advanced adrenarche signs born to consanguineous parents. He was born at term with ambiguous genitalia. At 15 days of age, he underwent replacement therapy with hydrocortisone and fludrocortisone due to a salt wasting (SW) crisis and adrenal insufficiency. At 3.5 years, he was admitted again with SW crisis attributed to the low – unadjusted to body surface area – hydrocortisone dose and presented with bilateral gynecomastia and adrenarche. At 8.5 years, his bone age was four years more advanced than his chronological age and he was prepubertal, with very high testosterone levels. Gas chromatography-mass spectrometry (GC-MS) urinary steroid metabolome analysis revealed the typical steroid metabolic fingerprint of 3β-HSD deficiency. Sequencing of the HSD3B2 gene identified in homozygosity the novel p.Lys36Ter nonsense mutation. Furthermore, this patient was found to be heterozygous for p.Val281Leu in the CYP21A2 gene. Both parents were identified as carriers of the p.Lys36Ter in HSD3B2.ConclusionsA novel nonsense p.Lys36Ter mutation in HSD3B2 was identified in a male patient with hypospadias. 3β-HSD deficiency due to mutations in the HSD3B2 gene is extremely rare and the finding of a patient with this rare type of disorders of sex development (DSD) is one of the very few reported to date. The complexity of such diseases requires a multidisciplinary team approach regarding the diagnosis and follow-up.

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