Modulation of the gut microbiota and short-chain fatty acid production by gac fruit juice and its fermentation in in vitro colonic fermentation.

This study aimed to investigate the effects of gac fruit juice and its probiotic fermentation (FGJ) utilizing Lactobacillus paracasei on the modulation of the gut microbiota and the production of short-chain fatty acids (SCFAs). We conducted a comparison between FGJ, non-fermented gac juice (GJ), and control samples through in vitro digestion and colonic fermentation using the human gut microbiota derived from fecal inoculum. Our findings revealed that both GJ and FGJ led to an increase in the viability of Lactobacilli, with FGJ exhibiting even higher levels compared to the control. The results from the 16S rDNA amplicon sequencing technique showed that both GJ and FGJ exerted positive impact on the gut microbiota by promoting beneficial bacteria, notably Lactobacillus mucosae and Bacteroides vulgatus. Additionally, both GJ and FGJ significantly elevated the levels of SCFAs, particularly acetic, propionic, and n-butyric acids, as well as lactic acid, in comparison to the control. Notably, FGJ exhibited a more pronounced effect on the gut microbiota compared to GJ. This was evident in its ability to enhance species richness, reduce the Firmicutes to Bacteroidetes (F/B) ratio, promote Akkermansia, and inhibit pathogenic Escherichia coli. Moreover, FGJ displayed enhanced production of SCFAs, especially acetic and lactic acids, in contrast to GJ. Our findings suggest that the probiotic fermentation of gac fruit enhances its functional attributes in promoting a balanced gut microbiota. This beverage demonstrates potential as a functional food with potential advantages for sustaining intestinal health.

Gas chromatography-flame ionization detector for sweat based COVID-19 screening.

Simple approach for rapid screening of corona virus disease 2019 (COVID-19) has been developed. This applied gas chromatography-flame ionization detector (GC-FID) analyzing the potential compound marker in sweat samples obtained from COVID-19 positive and negative volunteers in Bangkok, Thailand. The samples were collected by using cotton rods for 15 min, heated at 90 °C for 5 min, and the volatile compounds in the headspace (HS) were injected (5.00 mL) at 150 °C and separated within 13.7 min. The marker peak was tentatively identified as p-cymene by the authentic standard injection and comparison with the GC-mass spectrometry (GC-MS) and comprehensive two-dimensional GC (GC × GC)-MS analysis. Possible mechanisms for the presence of p-cymene were proposed. The marker peak area thresholds were then varied and optimized via construction of the receiver operating characteristic (ROC) curve. With the optimum threshold, the established method offered the accuracy, sensitivity and specificity of 96 %. This method was insignificantly affected (p-value >0.05) by genders, body mass indices, ages, and use of deodorants as well as the p-cymene containing food. However, the performance could be affected by the population with personal hygiene or experiencing the microbiomes producing p-cymene.

Development of a new paper-based voltage step electrocoagulation technique and application to wine classification.

This study developed a novel voltage step electrocoagulation (VSEC) technique on paper for analysis and classification of red wine samples. The concept relies on the electrode system applying voltage steps along a strip of filter paper soaked with a wine sample. The system employed a cathode array system (CAS) for voltage step application and an aluminium anode undergoing corrosion to form the green sludges responsible for wine color bleaching along the paper. The VSEC technique led to the shade of colors along the paper which can be observed by the naked-eye or using image processing software. The system was applied to classify 15 wine samples into different groups and to perform dilution and adulteration tests. In addition, the approach could be applied to approximate antioxidant properties of the wine samples as observed via the correlation between the results from VSEC and IC50 values obtained from the DPPH assay with an R2 of 0.76.

Miniaturized electrocoagulation approach for removal of polymeric pigments and selective analysis of non- and mono-hydroxylated phenolic acids in wine with HPLC-UV.

Electrocoagulation (EC) approach was developed to allow fast sample cleanup step prior to selective analysis of non- and mono-hydroxylated phenolic acids in red wine samples with high performance liquid chromatography hyphenated with UV detection (HPLC-UV). EC system with the wine in KCl(aq) electrolyte (1.5 mol L-1) was employed removing the polymeric pigments with good recovery of 39 peaks from 64 peaks. The mechanisms mainly involve enrichment induced aggregation and reduction of the pigments at the cathode and the adsorption onto the EC sludge. The EC was further miniaturized employing two intercalated stainless steel spring electrodes at 9.0 V which allowed removal of >99% interference peak area from the pigments within 5 s. The recoveries of the target phenolic acids (p-hydroxybenzoic acid, vanillic acid, syringic acid and ferulic acid) were within the range of 86-102%. The repeated analysis of these standards revealed <2 and ≤10% RSD of the intra-day and inter-day precisions, respectively. The linearities of their calibration curves were observed with R 2 > 0.99. Their method detection limits were within the range of 0.02-0.20 mg L-1.

Thin layer chromatography based extraction approaches for improved analysis of volatile compounds with gas chromatography-mass spectrometry and direct analysis with gas analyzer.

In this study, thin-layer chromatography was applied for selective extraction of volatile compounds in perfume prior to analysis with solid phase microextraction and gas chromatography-mass spectrometry. The standard compounds were desorbed from the thin-layer chromatography plate and extracted at 80°C for 15 min showing good linearity of the calibration curves (R2  > 0.98) and acceptable recovery range (65-81%). The plate after the separation was cut into four smaller parts followed by solid phase microextraction/gas chromatography-mass spectrometry analysis, which revealed different compound profile in each part with the correlation between log P of the standard compounds and their positions along the thin-layer chromatography plate (R2  = 0.65). This approach was applied to analyze perfume compounds in the sample with strong matrix interference from the synthetic agarwood. Terpene hydrocarbons (woody-based odors), ketones/esters, aldehydes, ethers, and alcohols were mostly observed at 8 ± 1, 6 ± 1, 5 ± 2, 4 ± 2, and 3 ± 2 cm, respectively, from the bottom of the thin-layer chromatography plate. While, the conventional solid phase microextraction/gas chromatography-mass spectrometry analysis of this sample solution revealed only 62 compounds (including 35 perfume compounds), the four-piece approach resulted in 109 compounds (62 perfume compounds). Furthermore, the capability of thin-layer chromatography-Gas Analyzer approach to analyze the isomers in this complex sample was demonstrated.

Cryogen-free comprehensive heartcut multidimensional gas chromatography using a Deans switch for improved analysis of petrochemical products derived from palmitic acid oxidation.

Comprehensive heartcut multidimensional gas chromatography was applied with example application for analysis of a sample obtained from palmitic acid oxidation in a Rancimat instrument. The system utilized a single Deans switch (DS) located between first dimensional semi-standard nonpolar (30 m) and second dimensional polar (60 m) columns. A cyclic multiple heartcut strategy consisting of 150 heartcuts with a 0.2 min window was applied offering comprehensive analysis and injection of a narrow band of compounds onto the second column without use of cryogenic trapping devices. Untargeted compound analysis of the sample prepared by solid phase micro-extraction was performed based on match between the experimental MS spectra and first dimensional retention indices with that from the NIST library. The sample contained the major compounds of 2-octanone, 1-methylcyclohexanol, 2,3,6-trimethylphenol, 3-phenylpropanol and 2-nonanone. This approach was then evaluated based on peak capacity and the number of identified compounds. Compared with one dimensional gas chromatography providing a total peak capacity of 172 and 43 identified compounds, the analysis performance was much more improved with a capacity of 5840 and 235 identified compounds by using comprehensive heartcut multidimensional gas chromatography with the total analysis time of 15.3 h. By comparison within the same set of identified compounds, the one dimensional and multidimensional approaches provided the MS match scores of 769 ± 81 and 836 ± 88, respectively. In addition, the nonlinear relationship between the analysis time and number of identifiable peaks was calculated according to the set of 235 compounds. This revealed that the analysis time could be shortened with the compensation of lower separation performance, where application of a 2.5 min heartcut window with the total analysis time of 1.2 h could result in the total peak capacity of 390 with 150 identifiable compounds.

Simultaneous determination of benzoic acid, sorbic acid, and propionic acid in fermented food by headspace solid-phase microextraction followed by GC-FID.

A simple and environmentally friendly method was developed for simultaneous determination of benzoic acid, sorbic acid, and propionic acid in fermented food samples. The analytes were extracted and pre-concentrated by headspace solid-phase microextraction (HS-SPME) and analysed by GC-FID. Central composite design (CCD) was conducted for the optimization of HS-SPME conditions. Under optimal conditions, a good linear range was obtained in the range of 5-150 mg L-1. The limit of detection (LOD) values were 1.1-1.7 mg L-1. The developed method was successfully applied to determine the concentration of three organic acid preservatives in various fermented food samples, including thai shrimp paste, pickled vegetables, soy sauce and fish sauce, with high accuracy (recoveries were between 83% and 109%) and good precision (%RSD was less than 6.0% and 4.5% for intra-day and inter-day, respectively).

Online preconcentration and determination of chondroitin sulfate, dermatan sulfate and hyaluronic acid in biological and cosmetic samples using capillary electrophoresis.

Capillary electrophoresis with large-volume sample stacking using an electroosmotic flow pump was developed for the determination of chondroitin sulfate, dermatan sulfate, and hyaluronic acid. Central composite design was used to simultaneously optimize the parameters for capillary electrophoresis separation. The optimized capillary electrophoresis conditions were 200 mM sodium dihydrogen phosphate, 200 mM butylamine, and 0.5% w/v polyethylene glycol as a background electrolyte, pH 4 and -16 kV. Exploiting large-volume sample stacking using an electroosmotic flow pump, the sensitivity of the proposed capillary electrophoresis system coupled with UV detection was significantly improved with limits of detection of 3, 5, 1 mg/L for chondroitin sulfate, dermatan sulfate, and hyaluronic acid, respectively. The developed method was applied to the determination of chondroitin sulfate and hyaluronic acid in cell culture media, cerebrospinal fluid, cosmetic products, and supplementary samples with highly acceptable accuracy and precision. Therefore, the proposed capillary electrophoresis approach was found to be simple, rapid, and reliable for the determination of chondroitin sulfate, dermatan sulfate, and hyaluronic acid in cell culture media, cerebrospinal fluid, cosmetic, and supplementary samples without sample pretreatment.

Identification of Volatile Compounds and Selection of Discriminant Markers for Elephant Dung Coffee Using Static Headspace Gas Chromatography-Mass Spectrometry and Chemometrics.

Elephant dung coffee (Black Ivory Coffee) is a unique Thai coffee produced from Arabica coffee cherries consumed by Asian elephants and collected from their feces. In this work, elephant dung coffee and controls were analyzed using static headspace gas chromatography hyphenated with mass spectrometry (SHS GC-MS), and chemometric approaches were applied for multivariate analysis and the selection of marker compounds that are characteristic of the coffee. Seventy-eight volatile compounds belonging to 13 chemical classes were tentatively identified, including six alcohols, five aldehydes, one carboxylic acid, three esters, 17 furans, one furanone, 13 ketones, two oxazoles, four phenolic compounds, 14 pyrazines, one pyridine, eight pyrroles and three sulfur-containing compounds. Moreover, four potential discriminant markers of elephant dung coffee, including 3-methyl-1-butanol, 2-methyl-1-butanol, 2-furfurylfuran and 3-penten-2-one were established. The proposed method may be useful for elephant dung coffee authentication and quality control.

Combination of vitamin E and vitamin C alleviates renal function in hyperoxaluric rats via antioxidant activity.

Hyperoxaluria and oxidative stress are risk factors in calcium oxalate (CaOx) stone formation. Supplement with antioxidant could be effective in prevention of recurrent stone formation. The present study aims to evaluate the protective effects of vitamin E and vitamin C in hyperoxaluric rat. The experiment was performed in rats for 21 days. Rats were divided into 5 groups as follows: control (group 1, n=8), hyperoxaluric rats (group 2, n=8), hyperoxaluric rats with vitamin E supplement (group 3, n=7), hyperoxaluric rats with vitamin C supplement (group 4, n=7) and hyperoxaluric rats with vitamin E and C supplement (group 5, n=7). Hyperoxaluria was induced by feeding hydroxyl L-proline (HLP) 2% w/v dissolved in drinking water. Intraperitoneal 200 mg/kg of vitamin E was given in groups 3 and 5 on days 1, 6, 11 and 16, while 500 mg of vitamin C was injected intravenously in groups 4 and 5 on days 1 and 11. Renal functions and oxidative status were measured. The urinary oxalate excretion was increased in HLP supplement rats, while glomerular filtration rate, proximal water and sodium reabsorption were significantly lower in group 2 compared with a control (P<0.05). Giving antioxidants significantly lower urinary calcium oxalate crystals (P<0.05). Hyperoxaluric rats had higher plasma malondialdehyde (PMDA) and lower urinary total antioxidant status (UTAS), which were alleviated by vitamin E and/or vitamin C supplement. In conclusion, giving combination of vitamin E and vitamin C exerts a protective role against HLP-induced oxalate nephropathy.

Determination of Mycotoxins in Brown Rice Using QuEChERS Sample Preparation and UHPLC-MS-MS.

QuEChERS sample preparation was optimized and validated using solvent extraction with 10% (v/v) acetic acid-containing acetonitrile in the presence of four salts (anh. MgSO4, NaCl, sodium citrate tribasic dihydrate and sodium citrate dibasic sesquihydrate) and dispersive solid-phase extraction with mixed sorbents (octadecylsilane, primary and secondary amine and silica sorbents) for an ultra high performance liquid chromatography-tandem mass spectrometric determination of nine mycotoxins in brown rice: aflatoxins (AFB1, AFB2, AFG1 and AFG2), fumonisins (FB1 and FB2), deoxynivalenol, ochratoxin A and zearalenone (ZON). Our developed method allows for the determination of trace levels of mycotoxins with method detection limits in the range of 1.4-25 µg/kg, below the maximum limits of EU regulations, and with an acceptable accuracy and precision, and recoveries in the range of 81-101% with relative standard deviations of 5-19% over a mycotoxin concentration range of 5.0-1,000 µg/kg. Six out of fourteen real samples of brown rice were found to be contaminated with at least one of these mycotoxins, ranging from 2.49-5.41 µg/kg of FB1, 4.33 ± 0.04 µg/kg of FB2 and 6.10-14.88 µg/kg of ZON.

Separation selectivity patterns of fully charged achiral compounds in capillary electrophoresis with a neutral cyclodextrin.

Based on the separation selectivity equation, related to the dimensionless parameters for fully charged achiral analytes using a neutral CD, the separation selectivity can be classified into seven patterns. With respect to CZE without CD, the presence of CD in the buffer may improve, or reduce, the separation selectivity with this effect being accompanied by the same or reversed electrophoretic mobility order for charged analytes. This can depend on the separation selectivity of the two analytes in free solution, the binding selectivity, the separation selectivity of analyte-CD complexes and the ratio of electrophoretic mobility of the analytes in free, and complexed forms. Using positional isomers of benzoic acids and phenoxy acids as test analytes and α-CD as a selector, the observed separation selectivity shapes were found to be in excellent agreement with the predicted separation selectivities.

Investigation of neutral monolithic capillary columns with varying n-alkyl chain lengths in capillary electrochromatography.

Two different neutral nonpolar monolithic columns series (designated as A and B columns series) each consisting of three columns at varying n-alkyl chain length were prepared by the copolymerization of the functional monomers C8-methacrylate, C12-acrylate, or C16-methacrylate with the cross-linking monomer pentaerythritol triacrylate (PETA) to yield monoliths with surface bound C8, C12, and C16 chains. In the A columns series, the composition of the functional monomers and crosslinker was adjusted to yield comparable chromatographic retention regardless of the alkyl chain length. In the B columns series, the composition of the functional monomers and crosslinker was kept constant yielding chromatographic retention, which increased as expected in the order of increasing the n-alkyl chain length. Due to their direct influences on the monolith porosity and retention energetic, the nature and composition of the monomers at a given porogen composition have largely affected the solute's mass transfer characteristics and sorption kinetics, as assessed by the van Deemter plots and separation efficiencies. The C16-monolith of the A series yielded the highest separation efficiency toward small solutes, but the A columns series were inadequate for protein separation. The C8-monolith of the B series provided the best separation efficiency for proteins while for tryptic peptide mapping, the C16-monolith of the A series seems to provide the best separation. For large protein molecules, the energetically "softer" C8 surface allowed faster sorption kinetics and in turn improved efficiency, while an energetically "harder" C16 surface favored better separation of the smaller size peptide solutes.

Determination of steroids adulterated in liquid herbal medicines using QuEChERS sample preparation and high-performance liquid chromatography.

QuEChERS sample preparation was optimized using solvent extraction with acetonitrile and dispersive-solid phase extraction with primary and secondary amine sorbents, and validated for high-performance liquid chromatographic determination of nine steroids commonly used to adulterate herbal medicines: such as triamcinolone, prednisolone, hydrocortisone, methylprednisolone, betamethasone, dexamethasone, beclomethasone, fludrocortsone acetate and cortisone acetate. Satisfactory extraction recoveries of 91-113% for all nine steroids were obtained, along with an acceptable precision in extraction recoveries shown by R.S.D. of ≤4.6 and 3.2% for intraday and interday, respectively. The QuEChERS sample preparation developed here allows the reliable detection of adulterated steroids with the limits of detection in the range of 0.06-0.17ppm. Adulterated steroids in three out of six real commercial liquid herbal medicines were found, such as 1.6 and 8.8ppm dexamethasone and 0.43ppm prednisolone.

Theoretical models of separation selectivity for charged compounds in micellar electrokinetic chromatography.

Equations and theoretical models for MEKC separation selectivity (α(MEKC) ) were established to explain a change in separation and electrophoretic mobility order of fully charged analytes, in which α(MEKC) is related to the dimensionless values of mobility selectivity in CZE (α(CZE)) and retention selectivity (α(k)) in MEKC, and where α(CZE) and α(k) are defined as the ratio of electrophoretic mobility in CZE and the ratio of retention factor (k) in MEKC for two charged analytes, respectively. Using four alkylparabens as test analytes, excellent agreement was found between the observed α(MEKC) and the proposed α(MEKC) models of test analytes in MEKC over a wide range of SDS concentrations and values of k. For example, in comparison with CZE separation of charged analytes, MEKC separation can enhance separation selectivity up to the maximum value when the selectivity ratio (ρ) is greater than 1.0 (ρ=α(k)/α(CZE)), while lower separation selectivity is obtained with ρ<1.0 (α(CZE) >α(k) >1).

Comparison and prediction of the retention in micellar electrokinetic chromatography and microemulsion electrokinetic chromatography for disubstituted benzenes.

Retention index (I), rather than retention factor (k), was found to be a more reasonable parameter for comparison of the relative affinity of disubstituted benzenes in MEEKC and MEKC, due to independent of I with the SDS surfactant concentration. MEKC and MEEKC may give similar or different I values, depending on types of moieties. With known I and K(ow) for alkylbenzenes as references in MEKC and MEEKC, the values of K(ow) for disubstituted benzenes can be estimated from the observed I values, where K(ow) is the octanol-water distribution constant. In addition, a group additive approach can be used to predict I for disubstituted benzenes with different moieties from the average observed I for the disubstituted benzenes with same moieties. However, electronic effects and/or intramolecular interaction may result in the different observed I from prediction.

Selectivity comparisons of monolithic silica capillary columns modified with poly(octadecyl methacrylate) and octadecyl moieties for halogenated compounds in reversed-phase liquid chromatography.

Stationary phase selectivities for halogenated compounds in reversed-phase HPLC were compared using C18 monolithic silica capillary columns modified with poly(octadecyl methacrylate) (ODM) and octadecyl moieties (ODS). The preferential retention of halogenated benzenes on ODM was observed in methanol/water and acetonitrile/water mobile phases. In selectivity comparison of selected analytes on ODM and ODS, greater selectivities for halogenated compounds were obtained with respect to alkylbenzenes on an ODM column, while similar selectivities were observed with a homologous series of alkylbenzenes on ODM and ODS columns. These data can be explained by greater dispersive interactions by more densely packed octadecyl groups on the ODM polymer coated column together with the contribution of carbonyl groups in ODM side chains. For the positional isomeric separation of dihalogenated benzenes (ortho-, meta-, para-), the ODM column also provided better separation of these isomers for the adjacently eluted isomers that cannot be completely separated on an ODS column in the same mobile phase. These results imply that the ODM column can be used as a better alternative to the ODS column for the separation of other halogenated compounds.

Capillary zone electrophoresis for separation and analysis of hydroxycitric acid and hydroxycitric acid lactone: application to herbal products of Garcinia atroviridis Griff.

Capillary zone electrophoresis (CZE) was developed for quantitative determination of hydroxycitric acid and hydroxycitric acid lactone in herbal products of Garcinia atroviridis Griff. Resolution optimization was investigated by varying type, concentration and pH of buffers. Using the pH 9.2 buffer containing 30 mM Na(2)B(4)O(7), 90 mM NaH(2)PO(4) and 0.5 mM tetradecyltrimethyl ammonium bromide, baseline resolution (R(s)>1.5) was found for all analytes. Advantages of the developed CZE method include simple sample preparation, fast analysis time within 5 min and high accuracy and precision.

Comparison of resolution in microemulsion EKC and MEKC employing suppressed electroosmosis: application to bisphenol-A-diglycidyl ether and its derivatives.

The resolution (R(s)) of hydrophobic analytes in microemulsion EKC (MEEKC) and MEKC with suppressed electroosmosis was investigated using bisphenol-A-diglycidyl ether and its derivatives (BADGEs) as test analytes. Separation scales were compared using our equation for the resolution, R(s)= (square rootN/4)(alpha-1)/(1+K(2)),where k is the retention factor, alpha the selectivity (alpha = k(2)/k(1) for k(2) > or = k(1)>0), and N the average efficiency. At given concentrations of SDS and organic cosolvent in the buffer, in comparison with MEKC, MEEKC was found to provide better resolution of BADGEs, mainly due to the significantly smaller k in MEEKC, but not the greater alpha in MEEKC, while a comparable range of N. Significantly improved resolution of BADGEs was obtained with increase in the concentration of organic cosolvent in the MEEKC and MEKC buffers, while small change in R(s) with the SDS concentration in a range of 100-180 mM. In addition, a decrease in temperature or voltage resulted in slightly better R(s).

Retention factor and retention index of homologous series compounds in microemulsion electrokinetic chromatography employing suppressed electroosmosis.

The retention factor (k) and retention index (I) of homologous series compounds such as alkylbenzenes (BZ), alkylaryl ketones, alkylbenzoates, and alkylparabens in microemulsion electrokinetic chromatography (MEEKC) with suppressed electroosmosis were investigated in a wide range of SDS concentrations ([SDS]), temperatures, and concentrations of organic cosolvents (phi). Using BZ as standards, the retention indices of other homologous series compounds were determined and they were found to be independent of [SDS] and temperature, while are dependent on the types and concentrations of organic cosolvents. The retention factor linearly increases with increasing [SDS], while linearly decreases with increasing temperature. The value of log k linearly decreases with increasing phi for methanol, ethanol, or ACN, while decreases by a second-degree polynomial with increasing phi for 2-propanol. Excellent agreement was found between the observed and predicted values of log k of analytes in MEEKC at given [SDS] and phi, where the predicted values were obtained from modified equations of the linear relationship of log k as functions of [SDS], the number of carbons, and phi. Therefore, both k and I can be used for peak identification of homologous series compounds.