Quantitative metabolomics based on gas chromatography mass spectrometry: status and perspectives

Metabolomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues (the metabolome). By analyzing differences between metabolomes using biostatistics (multivariate data analysis; pattern recognition), metabolites relevant to a specific phenotypic characteristic can be identified. However, the reliability of the analytical data is a prerequisite for correct biological interpretation in metabolomics analysis. In this review the challenges in quantitative metabolomics analysis with regards to analytical as well as data preprocessing steps are discussed. Recommendations are given on how to optimize and validate comprehensive silylation-based methods from sample extraction and derivatization up to data preprocessing and how to perform quality control during metabolomics studies. The current state of method validation and data preprocessing methods used in published literature are discussed and a perspective on the future research necessary to obtain accurate quantitative data from comprehensive GC-MS data is provided

HS-SPME/GC-MS methodologies for the analysis of volatile compounds in cork material

Two methods based on headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography– ion trap mass spectrometry (GC-IT/MS) were proposed for the analysis of volatile organic compounds (VOCs) in cork material used in the production of cork stoppers. The effect of various factors affecting the extraction efficiency was carried out by means of a 24 full factorial design. The first method allowed the extraction of 17 terpenes by using a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber (50/30 μm). The optimal conditions were achieved when cork extract (5 mL) added with 2.3 g of NaCl was extracted during 35 min at 55 °C. The second method allowed the identification of 41 carbonyl compounds after in-solution (5 mL) derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA, 2.3 mg/mL), followed by an incubation period of 6 min at 52 °C and extraction during 36 min at the same temperature, using a PDMS/DVB (50/30 μm) fiber. Both methods are simple, solvent free and fast. These methods were applied to the analysis of different cork raw material showing significant differences in the amounts of volatile compounds analyzed. Alcanfor and α-terpineol were the terpenes compounds present at highest amounts, and within carbonyl compounds analyzed, some samples presented a high level of butanal, octanal, nonanal, and glyoxal.info:eu-repo/semantics/publishedVersio

Rhinitis, Asthma and Respiratory Infections among Adults in Relation to the Home Environment in Multi-Family Buildings in Sweden

Risk factors for rhinitis, asthma and respiratory infections in the home environment were studied by a questionnaire survey. Totally 5775 occupants (>= 18 years old) from a stratified random sample of multi-family buildings in Sweden participated (46%). 51.0% had rhinitis in the last 3 months (current rhinitis); 11.5% doctor diagnosed asthma; 46.4% respiratory infections in the last 3 months and 11.9% antibiotic medication for respiratory infections in the last 12 months. Associations between home environment and health were analyzed by multiple logistic regression, controlling for gender, age and smoking and mutual adjustment. Buildings constructed during 1960-1975 were risk factors for day time breathlessness (OR = 1.53, 95%CI 1.03-2.29). And those constructed during 1976-1985 had more current rhinitis (OR = 1.43, 95%CI 1.12-1.84) and respiratory infections (OR = 1.46, 95%CI 1.21-1.78). Cities with higher population density had more current rhinitis (p = 0.008) and respiratory infections (p<0.001). Rented apartments had more current rhinitis (OR = 1.23, 95%CI 1.07-1.40), wheeze (OR = 1.20, 95%CI 1.02-1.41), day time breathlessness (OR = 1.31, 95%CI 1.04-1.66) and respiratory infections (OR = 1.13, 95%CI 1.01-1.26). Living in colder parts of the country was a risk factor for wheeze (p = 0.03) and night time breathlessness (p = 0.002). Building dampness was a risk factor for wheeze (OR = 1.42, 95%CI 1.08-1.86) and day time breathlessness (OR = 1.57, 95%CI 1.09-2.27). Building dampness was a risk factor for health among those below 66 years old. Odor at home was a risk factor for doctor diagnosed asthma (OR = 1.49, 95%CI 1.08-2.06) and current asthma (OR = 1.52, 95%CI 1.03-2.24). Environmental tobacco smoke (ETS) was a risk factor for current asthma (OR = 1.53, 95%CI 1.09-2.16). Window pane condensation was a risk factor for antibiotic medication for respiratory infections (OR = 1.41, 95%CI 1.10-1.82). In conclusion, rhinitis, asthma and respiratory infections were related to a number of factors in the home environment. Certain building years (1961-1985), building dampness, window pane condensation and odor in the dwelling may be risk factors