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1.
Nat Commun ; 15(1): 6363, 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39075060

ABSTRACT

Effective prevention strategies for post-COVID complications are crucial for patients, clinicians, and policy makers to mitigate their cumulative burden. This study evaluated the association of modifiable lifestyle factors (smoking, alcohol intake, BMI, physical activity, sedentary time, sleep duration, and dietary habits) with COVID-19 multisystem sequelae, death, and hospitalization in the UK Biobank cohort (n = 68,896). A favorable lifestyle (6-10 healthy factors; 46.4%) was associated with a 36% lower risk of multisystem sequelae (HR, 0.64; 95% CI, 0.58-0.69; ARR at 210 days, 7.08%; 95% CI, 5.98-8.09) compared to an unfavorable lifestyle (0-4 factors; 12.3%). Risk reductions spanned all 10 organ systems, including cardiovascular, coagulation, metabolic, gastrointestinal, kidney, mental health, musculoskeletal, respiratory disorders, and fatigue. This beneficial effect was largely attributable to direct lifestyle impacts independent of corresponding pre-infection comorbidities (71% for any sequelae). A favorable lifestyle was also related to the risk of post-COVID death (HR 0.59, 0.52-0.66) and hospitalization (HR 0.78, 0.73-0.84). These associations persisted across acute and post-acute infection phases, irrespective of hospitalization status, vaccination, or SARS-CoV-2 variant. These findings underscore the clinical and public health importance of adhering to a healthy lifestyle in mitigating long-term COVID-19 adverse impacts and enhancing future pandemic preparedness.


Subject(s)
COVID-19 , Hospitalization , Life Style , SARS-CoV-2 , Humans , COVID-19/mortality , COVID-19/epidemiology , COVID-19/prevention & control , Hospitalization/statistics & numerical data , Male , Female , Middle Aged , Aged , Risk Factors , United Kingdom/epidemiology , Adult , Smoking/epidemiology , Smoking/adverse effects , Exercise , Alcohol Drinking/adverse effects , Alcohol Drinking/epidemiology , Post-Acute COVID-19 Syndrome , Cohort Studies , Sedentary Behavior
2.
Nat Commun ; 15(1): 4031, 2024 May 13.
Article in English | MEDLINE | ID: mdl-38740772

ABSTRACT

The rapid global distribution of COVID-19 vaccines, with over a billion doses administered, has been unprecedented. However, in comparison to most identified clinical determinants, the implications of individual genetic factors on antibody responses post-COVID-19 vaccination for breakthrough outcomes remain elusive. Here, we conducted a population-based study including 357,806 vaccinated participants with high-resolution HLA genotyping data, and a subset of 175,000 with antibody serology test results. We confirmed prior findings that single nucleotide polymorphisms associated with antibody response are predominantly located in the Major Histocompatibility Complex region, with the expansive HLA-DQB1*06 gene alleles linked to improved antibody responses. However, our results did not support the claim that this mutation alone can significantly reduce COVID-19 risk in the general population. In addition, we discovered and validated six HLA alleles (A*03:01, C*16:01, DQA1*01:02, DQA1*01:01, DRB3*01:01, and DPB1*10:01) that independently influence antibody responses and demonstrated a combined effect across HLA genes on the risk of breakthrough COVID-19 outcomes. Lastly, we estimated that COVID-19 vaccine-induced antibody positivity provides approximately 20% protection against infection and 50% protection against severity. These findings have immediate implications for functional studies on HLA molecules and can inform future personalised vaccination strategies.


Subject(s)
Alleles , Antibodies, Viral , COVID-19 Vaccines , COVID-19 , HLA Antigens , Polymorphism, Single Nucleotide , SARS-CoV-2 , Humans , COVID-19 Vaccines/immunology , COVID-19 Vaccines/administration & dosage , COVID-19/immunology , COVID-19/prevention & control , COVID-19/genetics , COVID-19/virology , SARS-CoV-2/immunology , SARS-CoV-2/genetics , Antibodies, Viral/immunology , Antibodies, Viral/blood , HLA Antigens/genetics , HLA Antigens/immunology , Antibody Formation/genetics , Antibody Formation/immunology , Male , Female , Genotype , Vaccination , Middle Aged , Adult , Genetic Variation , HLA-DQ beta-Chains/genetics , HLA-DQ beta-Chains/immunology , Breakthrough Infections
3.
Dev Neurorehabil ; 26(1): 63-70, 2023 Jan.
Article in English | MEDLINE | ID: mdl-35833864

ABSTRACT

OBJECTIVE: To examine the feasibility of a home-based hybrid Bimanual-Intensive-Therapy combined with modified Constraint-Induced-Movement-Therapy (h-BITmCI) in children with spastic unilateral cerebral palsy (SUCP) with low and very low bimanual functional level. METHODS: A single-group of 10 children aged 5-8 years old, performed the hybrid home Bimanual-Intensive-Therapy (BIT, 80 hours) combined with modified Constraint-Induced-Movement-Therapy (mCIMT, 20 hours): h-BITmCI. Thus, Bimanual Functional Performance (BFP), Quality of Life (QoL) and expectations from families were measured through the Assisting Hand Assessment, (AHA), Pediatric Quality of Life Inventory, for Cerebral Palsy, (PedsQLTM v. 3.0, CP) and a specific questionnaire for families for baseline period (week 0), during the treatment phase (week 4 and week 8) and after the intervention (week 10). Repeated measures ANOVA analysis (with post hoc test correction) was used for the BFP and QoL, with a confidence interval (CI) of 95% and with p value <.008 considered statistically significant. RESULTS: Ten children completed the study with an average of 77-hours-BIT and 17-hours-mCIMT. None of the participants dropped out of the study during the follow-up process, and the parents' expectations were fulfilled, indicating high caregiver compliance. During the first 80 hours of BIT, a mean increase of 3.7 AHA units was obtained for the BFP (p = 1.00) and 1.64 points in the QoL (p = 1.00). Clinically relevant changes were observed in the last two weeks (20 hours mCIMT) with a mean increase of 10.6 AHA units in BFP and 6.29 points in QoL (p < .001). CONCLUSIONS: h-BITmCI protocol is feasible to be performed at home with the family's involvement, obtaining the greatest improvements after 100 hours of both therapies. Thus, mCIMT would be a relevant condition to increase the affected upper limb functionality, rather than the dosage used to obtain clinically relevant changes.


Subject(s)
Cerebral Palsy , Quality of Life , Child , Humans , Child, Preschool , Feasibility Studies , Treatment Outcome , Physical Therapy Modalities , Upper Extremity
4.
J Agric Food Chem ; 70(29): 9143-9153, 2022 Jul 27.
Article in English | MEDLINE | ID: mdl-35819924

ABSTRACT

ß-Carbolines (ßCs) are naturally occurring bioactive alkaloids, whereas α-dicarbonyl compounds are reactive substances generated in foods and in vivo. In this work, l-tryptophan reacted with α-dicarbonyl compounds affording new ß-carbolines. Glyoxal afforded 1-hydroxymethyl-ß-carboline (HME-ßC) and its 3-carboxylic acid, and methylglyoxal afforded 1-(1-hydroxyethyl)-ß-carboline (HET-ßC) and its 3-carboxylic acid. 3-Deoxyglucosone afforded 1-(1,3,4,5-tetrahydroxypent-1-yl)-ß-carboline isomers (1a/b), 1-(1,4,5-trihydroxypent-1-yl)-ß-carboline (2), and 1-(1,5-dihydroxypent-3-en-1-yl)-ß-carboline (3). The formation of these ßCs increased under acidic conditions and with increasing temperature. A mechanism is proposed explaining the conversion of a carbonyl into a hydroxy group based on tautomerism and cyclization to the dihydro-ßC-3-COOH intermediates, which were isolated and gave the ßCs. These α-dicarbonyl-derived ßCs occurred in model reactions of l-tryptophan with fructose or glucose incubated under heating and can be considered as advanced glycation end products (AGEs). They were also present in foods and formed during heating processes. HET-ßC appeared in processed foods, reaching up to 309 ng/g, with the highest amount found in dried tomato, fried onion, toasted bread, and Manuka honey. HME-ßC was only detected in some foods with lower amounts than HET-ßC. HET-ßC appeared in foods as a racemic mixture of enantiomers suggesting the same mechanism of formation as the synthetized product. α-Dicarbonyl-derived ßCs (HET-ßC, HME-ßC, and 1a/b-3) occur in foods and food processing and, therefore, they are ingested during diet.


Subject(s)
Alkaloids , Tryptophan , Carbolines , Carboxylic Acids
5.
J Hazard Mater ; 431: 128532, 2022 06 05.
Article in English | MEDLINE | ID: mdl-35248958

ABSTRACT

A comparative analysis of toxicities of both arsenic forms (arsenite and arsenate) in the model eukaryotic microorganism Tetrahymena thermophila (ciliate protozoa) has shown the presence of various detoxification mechanisms and cellular effects comparable to those of animal cells under arsenic stress. In the wild type strain SB1969 arsenate is almost 2.5 times more toxic than arsenite. According to the concentration addition model used in binary metallic mixtures their toxicities show an additive effect. Using fluorescent assays and flow cytometry, it has been detected that As(V) generates elevated levels of ROS/RNS compared to As(III). Both produce the same levels of superoxide anion, but As(V) also causes greater increases in hydrogen peroxide and peroxynitrite. The mitochondrial membrane potential is affected by both As(V) and As(III), and electron microscopy has also revealed that mitochondria are the main target of both arsenic ionic forms. Fusion/fission and swelling mitochondrial and mitophagy, together with macroautophagy, vacuolization and mucocyst extruction are mainly associated to As(V) toxicity, while As(III) induces an extensive lipid metabolism dysfunction (adipotropic effect). Quantitative RT-PCR analysis of some genes encoding antioxidant proteins or enzymes has shown that glutathione and thioredoxin metabolisms are involved in the response to arsenic stress. Likewise, the function of metallothioneins seems to be crucial in arsenic detoxification processes, after using both metallothionein knockout and knockdown strains and cells overexpressing metallothionein genes from this ciliate. The analysis of the differential toxicity of As(III) and As(V) shown in this study provides cytological and molecular tools to be used as biomarkers for each of the two arsenic ionic forms.


Subject(s)
Arsenic , Arsenites , Tetrahymena thermophila , Animals , Arsenates/metabolism , Arsenates/toxicity , Arsenic/metabolism , Arsenic/toxicity , Arsenites/metabolism , Arsenites/toxicity , Metallothionein , Tetrahymena thermophila/genetics
6.
BMJ Open ; 11(12): e049286, 2021 12 02.
Article in English | MEDLINE | ID: mdl-34857560

ABSTRACT

INTRODUCTION: The main treatment for sleep apnoeas and hypopnoeas syndrome (SAHS) is continuous positive airway pressure (CPAP). However, patients sometimes do not adhere to the treatment protocol. Supplementary and complementary therapies have appeared as alternatives. Some of the therapies which are especially important are those related to myofunctional (MFT) and postural therapy (PT), as all of them are non-invasive, and their application is simpler than that of CPAP. We aim to present a protocol for a systematic review and meta-analysis for investigating new SAHS treatments, including the protocols and frequency of use and the effects they have on patient signs, symptoms and quality of life. METHODS AND ANALYSIS: The literature search will be conducted using the Cochrane, Web of Science, Medline (via PubMed) and Scopus databases, from January 2020 to December 2020. All types of studies written in English and Spanish that investigate the use of alternative SAHS treatments related to MFT, or more importantly, the combination of MFT and PRT, will be selected. To evaluate their quality, the Critical Appraisal Checklist for Analytical Cross-Sectional will be applied. The primary factor valued in the studies will be the inclusion of MFT and PT reeducation in the treatment. Subgroup analyses will be carried out evaluating the specific type of treatments chosen and the improvements or deteriorations in the level of health and quality of life in the patients. Finally, several patient-related outcomes, namely sleep quality, quality of life and sleep Apnoeas and Hypoapnoeas Index, will be examined. ETHICS AND DISSEMINATION: In this case, ethical approval is not necessary. The data used in the review will be exclusively obtained from published studies, implying there are no privacy concerns. The information obtained will be relevant to understand if the new treatments applied in SAHS are effective, and if postural and MFT therapy used together can be considered an appropriate approach to treat this disease.The results will be published in a peer-reviewed journal.


Subject(s)
Continuous Positive Airway Pressure , Sleep Apnea Syndromes , Cross-Sectional Studies , Humans , Meta-Analysis as Topic , Quality of Life , Sleep Apnea Syndromes/therapy , Systematic Reviews as Topic
7.
Chirality ; 31(10): 879-891, 2019 10.
Article in English | MEDLINE | ID: mdl-31429160

ABSTRACT

In this work, we study the effect of different variables affecting elution profile distortion on the enantiomeric resolution eventually achievable when working with on-line coupled liquid chromatography to gas chromatography (LC-GC). Specifically, the proposed configuration combines achiral reversed-phase liquid chromatography (RPLC) and chiral gas chromatography (enantio-GC), with heptakis-(2,3,6-tri-O-methyl)-ß-cyclodextrin as enantioselective stationary phase to analyse target fractions transferred (from LC to GC) via the through oven transfer adsorption desorption (TOTAD) interface. The high degree of orthogonality resulting from the combination of two chromatographic columns having very different separation mechanisms (and also requiring mobile phases in distinct physical states), as well as integration of the sample preparation step in the first dimension of the system, significantly contributed to exploit the performance of the proposed two-dimensional approach. Occasional adverse effects, which may result in severe peak distortions during LC-GC analysis and could be explained by flow instabilities due to viscous fingering, are circumvented by using the outstanding capacity of the TOTAD interface for achieving effective elimination of the eluent arriving from the LC preseparation.

8.
Sci Total Environ ; 598: 889-899, 2017 Nov 15.
Article in English | MEDLINE | ID: mdl-28458206

ABSTRACT

The Circular Mausoleum tomb (Roman Necropolis of Carmona, Spain) dates back from the first century AD and is characterized by a dense microbial (phototrophic) colonization on the walls and ceiling. However, some walls exhibited an important number of violet stains of unknown origin. The microbial communities of these violet stains are mainly composed of cyanobacteria, streptomycetes and fungi. A strain of Streptomyces parvus, isolated from the walls, produces a violet pigment in culture media. High performance liquid chromatography-mass spectrometry of the culture extracts obtained from this Streptomyces revealed the presence of a few granaticins, pigments with a benzoisochromanequinone structure. When metabolically active in the tomb, S. parvus synthesizes the pigments that diffuse into the mortar. During rain and/or wetting periods, the pigments are solubilized by alkaline waters and elute from the starting position to the surrounding mortar, enlarging the pigmented area and thus contributing to this exceptional biodeterioration phenomenon.

9.
Talanta ; 120: 23-9, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24468337

ABSTRACT

Total elimination of the eluent resulting from the pre-separation step is the critical point when coupling LC to GC. As a helium flow is applied during transfer to eliminate the solvent, the interface used for linking the two chromatographic systems must be properly sealed to prevent gas leaks and to achieve an effective evaporation of the eluent. The aim of this work was to improve the performance of the Through Oven Transfer Adsorption Desorption (TOTAD) interface to remove the eluent coming from LC by modifying the way in which the injector sealing system is held in place. As with the original design, the new approach makes it possible to transfer high volumes at a high rate, but the proposed modification also simplifies the experimental work because the displacement risk of the sealing system is reduced. Analyses of an ester mixture by RPLC-GC were performed to confirm the applicability of the system modification. In this work, volumes of up to 5 ml, at flow rates as high as 2 ml/min, were transferred from LC to GC with almost complete solvent removal even when working in reversed phase mode in the LC step.


Subject(s)
Chromatography, Gas/instrumentation , Chromatography, Reverse-Phase/instrumentation , Chromatography, Gas/economics , Chromatography, Reverse-Phase/economics , Equipment Design , Esters/isolation & purification , Solvents
10.
Sci Rep ; 4: 3610, 2014 Jan 09.
Article in English | MEDLINE | ID: mdl-24402302

ABSTRACT

The Etruscan civilisation originated in the Villanovan Iron Age in the ninth century BC and was absorbed by Rome in the first century BC. Etruscan tombs, many of which are subterranean, are one of the best representations of this culture. The principal importance of these tombs, however, lies in the wall paintings and in the tradition of rich burial, which was unique in the Mediterranean Basin, with the exception of Egypt. Relatively little information is available concerning the biodeterioration of Etruscan tombs, which is caused by a colonisation that covers the paintings with white, circular to irregular aggregates of bacteria or biofilms that tend to connect each other. Thus, these colonisations sometimes cover extensive surfaces. Here we show that the colonisation of paintings in Tomba del Colle is primarily due to bacteria of the order Rhizobiales (Alphaproteobacteria), which were likely influenced by the neighbouring rhizosphere community and the availability of nutrients from root exudates.


Subject(s)
Mortuary Practice , Rhizobiaceae/physiology , History, Ancient , Italy , Microscopy, Electron, Scanning , Molecular Sequence Data , Polymerase Chain Reaction , Rhizobiaceae/ultrastructure
11.
Food Chem ; 141(1): 542-7, 2013 Nov 01.
Article in English | MEDLINE | ID: mdl-23768391

ABSTRACT

A rapid and fully automated screening of chiral compounds in essential oils, aimed to the selection of natural sources of pure enantiomers of limonene and carvone, is performed by using on-line coupled reversed phase liquid chromatography with gas chromatography and mass spectrometry (RPLC-GC-MS). Essential oils obtained from Mentha spicata and Mentha piperita were analysed by direct injection into RPLC. The reported procedure includes fractionation and clean-up in RPLC, selection of the fraction to be transferred from RPLC to GC, trapping and concentration of the target compounds in the interface, thermal desorption and, finally, enantiomeric resolution and identification of chiral compounds by GC-MS. The presence of (S)-limonene and (R)-carvone as the unique enantiomeric forms existing for both compounds could be unambiguously established by transferring different volume fractions from RPLC to GC. Data obtained demonstrate high separation efficiency and well tunable selectivity in the on-line coupled RPLC-GC-MS analysis of chiral compounds.


Subject(s)
Chromatography, Reverse-Phase/methods , Gas Chromatography-Mass Spectrometry/methods , Mentha/chemistry , Oils, Volatile/chemistry , Plant Oils/chemistry , Molecular Structure , Stereoisomerism
12.
Magn Reson Chem ; 51(6): 350-7, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23625459

ABSTRACT

(1)H High resolution magic angle spinning (HRMAS) NMR spectroscopic data in combination with principal components analysis and analysis of variance were used to differentiate between irradiated and non-irradiated cold-smoked Atlantic salmon (Salmo salar). NMR profiling was obtained, with a spectral acquisition time of less than 8 min, from a small sample size of intact white salmon muscle, by non-destructive analysis that includes a very simple and rapid sample preparation step. Results obtained enable the use of creatine, trimethylamine oxide and the sum of phosphorylcholine and glycerophosphorylcholine as diagnostic compounds to detect irradiation treatment. This study shows the potential of (1)H-HRMAS to be a rapid method for investigating compositional changes due to food processing as well as to confirm the presence or absence of some bioactive compounds in irradiated samples.


Subject(s)
Food Handling , Magnetic Resonance Spectroscopy/standards , Salmo salar , Animals , Protons , Reference Standards , Salmon
13.
Sci Rep ; 3: 1440, 2013.
Article in English | MEDLINE | ID: mdl-23486535

ABSTRACT

The paintings from Tomba della Scimmia, in Tuscany, are representative of the heavy bacterial colonization experienced in most Etruscan necropolises. The tomb remained open until the late 70's when it was closed because of severe deterioration of the walls, ceiling and paintings after decades of visits. The deterioration is the result of environmental changes and impacts suffered since its discovery in 1846. We show scanning electron microscopy and molecular studies that reveal the extent and nature of the biodeterioration. Actinobacteria, mainly Nocardia and Pseudonocardia colonize and grow on the tomb walls and this process is linked to the availability of organic matter, phyllosilicates (e.g. clay minerals) and iron oxides. Nocardia is found metabolically active in the paintings. The data confirm the specialization of the genera Nocardia and Pseudonocardia in the colonization of subterranean niches.


Subject(s)
Actinobacteria/isolation & purification , Paintings , Actinobacteria/classification , Actinobacteria/genetics , Aluminum Silicates/chemistry , Calcium Carbonate/chemistry , Clay , Ferric Compounds/chemistry , Italy , Microscopy, Electron, Scanning , Nocardia/classification , Nocardia/genetics , Nocardia/isolation & purification , Phylogeny , RNA, Ribosomal, 16S/chemistry , RNA, Ribosomal, 16S/genetics , Sequence Analysis, RNA
14.
J Sci Food Agric ; 93(3): 479-84, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22806617

ABSTRACT

BACKGROUND: As radiation-induced alterations of the lipid fraction of foods are related to their initial fat content, concentrations of fat degradation products used as irradiation markers are expected to be lower when irradiating low-fat-containing foods. Thus the sensitivity required when applying analytical methods for identifying irradiation markers in foods eventually depends on their respective amounts of fat. The aim of this study was to perform the qualitative analysis of characteristic hydrocarbons resulting from irradiation of samples with a fat content as low as 25 g kg(-1). RESULTS: A rapid extraction using a small amount of ethyl acetate was the unique sample pretreatment required to accomplish the analysis of radiolytic markers by using on-line coupling of reverse phase liquid chromatography and gas chromatography with mass spectrometry detection (RPLC/GC/MS). Efficient elimination of the large volumes (up to 2170 µL) directly transferred from LC to GC was achieved by optimising the operation mode of the through-oven transfer adsorption/desorption system used as interface. CONCLUSION: The reported procedure allowed confirmation, in less than 65 min, of the occurrence of up to five irradiation markers, namely n-pentadecane, 1-hexadecene, 1,7-hexadecadiene, n-heptadecane and 8-heptadecene, in cooked ham irradiated at doses as low as 2 kGy.


Subject(s)
Alkanes/analysis , Alkenes/analysis , Dietary Fats/analysis , Dietary Fats/radiation effects , Food Analysis/methods , Food Irradiation , Animals , Chromatography, High Pressure Liquid , Gas Chromatography-Mass Spectrometry , Meat/analysis , Swine
15.
Chirality ; 24(5): 420-6, 2012 May.
Article in English | MEDLINE | ID: mdl-22517436

ABSTRACT

Enantiomeric composition of selected chiral compounds present in complex mixtures is determined by using the online coupling of reversed-phase liquid chromatography (LC) to gas chromatography (GC) and mass spectrometry. Integration of sample preparation into GC analysis, in a completely automated way, is achieved by means of the effective clean-up resulting from both the LC fractionation step and the eluent elimination provided by the through oven transfer adsorption desorption system used for LC-GC interfacing. The possibilities of the technique are illustrated through some examples concerning the stereodifferentiation in essential oils of major and minor chiral compounds via LC-GC transfer of different volume fractions, ranging from 0.5 to 1.9 ml, which show the significance of the window size for the determination of enantiomeric profiles.


Subject(s)
Chromatography, Reverse-Phase/methods , Gas Chromatography-Mass Spectrometry/methods , Cyclohexane Monoterpenes , Cyclohexenes/analysis , Cyclohexenes/chemistry , Limit of Detection , Limonene , Monoterpenes/analysis , Monoterpenes/chemistry , Oils, Volatile/analysis , Oils, Volatile/chemistry , Online Systems , Reproducibility of Results , Stereoisomerism , Terpenes/analysis , Terpenes/chemistry
16.
Magn Reson Chem ; 48(9): 693-703, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20641130

ABSTRACT

High-resolution magic angle spinning (HRMAS) NMR spectroscopic data of smoked Atlantic salmon (Salmo salar) were fully assigned by combination of one- and two-dimensional-HRMAS experiments. Complete representative spectra, obtained after few minutes of analysis time, revealed a large number of minor and major compounds in the sample. The methodology is limited by the low sensitivity of NMR, and therefore HRMAS only enables the determination of the most relevant components. These were fatty acids (FAs), carbohydrates, nucleoside derivatives, osmolytes, amino acids, dipeptides and organic acids. For the first time, spectra were resolved sufficiently to allow semiquantitative determination in intact muscle of the highly polyunsaturated FA 22:6 omega-3. Additionally, the feasibility of (1)H-HRMAS NMR metabolite profiling was tested to identify some bioactive compounds during storage. This profiling was carried out by the non-destructive and direct analysis (i.e. without requiring sample preparation and multiple step procedures) of intact salmon muscle. The proposed procedure can be applied to a large number of samples with high throughput due to the short time of analysis and quick evaluation of the data.


Subject(s)
Food Handling/methods , Salmo salar , Seafood/analysis , Smoke , Acids/analysis , Amino Acids/analysis , Animals , Carbohydrates/analysis , Carbohydrates/chemistry , Dipeptides/analysis , Fatty Acids/analysis , Fatty Acids/chemistry , Magnetic Resonance Spectroscopy , Muscles/chemistry , Nucleosides/analysis , Nucleosides/chemistry , Osmosis , Protons , Reference Standards , Smoke/analysis
17.
J Agric Food Chem ; 58(2): 752-6, 2010 Jan 27.
Article in English | MEDLINE | ID: mdl-20025225

ABSTRACT

The usefulness of both solid phase microextraction (SPME) and multidimensional gas chromatography (MDGC) coupled to mass spectrometry (MS) to detect chiral compounds in irradiated cheese was evaluated. The enantiomeric resolution of relevant chiral aroma compound was achieved by analyzing the extracts obtained from SPME by means of a permethylated beta-CD stationary phase as the main column of the multidimensional system to separate specific selected cuts containing components unresolved in the first dimension. The proposed procedure allowed to determine, in less than 90 min, that no significant variations had been produced in the stereoisomeric distribution of limonene, 3-hydroxybutanone, and 2,3-butanediol in cheese when applying irradiation doses ranging from 0 to 8 kGy.


Subject(s)
Cheese/analysis , Chromatography, Gas/methods , Food Irradiation , Organic Chemicals/chemistry , Animals , Cattle , Chromatography, Gas/instrumentation , Stereoisomerism
18.
J Chromatogr A ; 1211(1-2): 99-103, 2008 Nov 21.
Article in English | MEDLINE | ID: mdl-18922537

ABSTRACT

The use of absorbents as retaining materials in the through oven transfer adsorption desorption interface (TOTAD) of an on-line coupled reversed-phase liquid chromatography-gas chromatography system (RPLC-GC) is proposed for the first time. A comparative study of an adsorbent (Tenax TA) and two absorbents, namely polydimethylsiloxane and poly(50% phenyl/50% methylsiloxane) is performed to establish the best experimental conditions for the automated and simultaneous determination of 15 organophosphorus and organochlorine pesticide residues in olive oil. The proposed method provides satisfactory repeatability (RSDs lower, in general, than 8.5%) and sensitivity (limits of detection ranging from 0.6 to 81.9 microg/L) for the investigated compounds.


Subject(s)
Chromatography, Gas/methods , Chromatography, High Pressure Liquid/methods , Pesticides/analysis , Plant Oils/chemistry , Absorption , Adsorption , Chromatography, Gas/instrumentation , Chromatography, High Pressure Liquid/instrumentation , Dimethylpolysiloxanes/chemistry , Hydrocarbons, Chlorinated/analysis , Olive Oil , Organophosphorus Compounds/analysis , Reproducibility of Results , Sensitivity and Specificity , Siloxanes/chemistry , Temperature
19.
J Sep Sci ; 30(16): 2780-5, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17823897

ABSTRACT

A method based on the use of absorbents as packing materials inside the interface of the online coupling between RPLC and GC is proposed for the enantiomeric analysis of beta-pinene and limonene in essential oils. For that purpose, a comparison of the RSD, detection limit and recovery provided by two absorbents and one adsorbent is included in this study. The results found in this work proved the validity of absorbents as packing materials in online RPLC-GC to determine minor compounds in complex matrices. In particular, PDMS seemed to be specially useful to analyse nonpolar compounds, such as beta-pinene and limonene, since it provided higher sensitivity for this kind of compounds. The developed method was applied to the evaluation of the natural and non-natural character of commercial essential oils by means of the determination of the enantiomeric composition of beta-pinene and limonene.

20.
J Chromatogr A ; 1153(1-2): 29-35, 2007 Jun 15.
Article in English | MEDLINE | ID: mdl-17306811

ABSTRACT

A method based on the use of absorbents as packing materials in the interface of the direct coupling between reversed phase liquid chromatography and gas chromatography (RPLC-GC) is proposed. To that end, a comparative study on different adsorbents and absorbents was carried out. Specifically, Tenax TA and Gaschrom were used as adsorbents while polydimethylsiloxane and poly(50% phenyl:50% methylsiloxane) were the absorbents tested. Some experimental variables involved in the solvent elimination were separately optimised for adsorbent and absorbent materials. Relative standard deviations (RSD) lower than 10% were achieved in all cases but the use of absorbents showed interesting advantages with respect to adsorbents, namely a simpler performance of the experimental work, which facilitates the sample preparation step and the subsequent gas chromatographic analysis to be performed.


Subject(s)
Chromatography, Gas/methods , Chromatography, Liquid/methods , Absorption , Chromatography, Gas/instrumentation , Chromatography, Liquid/instrumentation , Dimethylpolysiloxanes , Online Systems , Polymers/chemistry , Silicones , Siloxanes
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