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A simple sample preparation method requiring minimal organic solvents is proposed for the determination of the total phthalate content in cosmetics by high-performance liquid chromatography-tandem mass spectrometry. The hydrolysis of phthalates and purification of interfering substances were performed in a three-phase system that included an upper n-hexane phase, a middle ethanol phase, and a lower aqueous alkali solution. This three-phase system utilized an incremental purification strategy. The apolar ingredients were extracted with n-hexane, the polar pigments accumulated in the ethanol phase, and the hydrolysis product, phthalic acid, remained in the hydrolysate. Under the optimized conditions, the correlation coefficients ( r) for the calibration curves were 0.998-0.999 in the range 0.60-12 mol L. The limit of detection was 5.1 μmol kg, and the limit of quantification was 9.2 μmol kg. The recoveries varied from 84 to 97% with RSDs equal to or lower than 11%. The intra-day and inter-day repeatability values, expressed as the relative standard deviation, were less than 8.7 and 9.8, respectively. No obvious matrix effect existed in the different cosmetics matrices. The validated method was applied for the analysis of 57 commercial cosmetic samples. [ABSTRACT FROM AUTHOR]

A simple sample preparation method requiring minimal organic solvents is proposed for the determination of the total phthalate content in cosmetics by high-performance liquid chromatography-tandem mass spectrometry. The hydrolysis of phthalates and purification of interfering substances were performed in a three-phase system that included an upper n-hexane phase, a middle ethanol phase, and a lower aqueous alkali solution. This three-phase system utilized an incremental purification strategy. The apolar ingredients were extracted with n-hexane, the polar pigments accumulated in the ethanol phase, and the hydrolysis product, phthalic acid, remained in the hydrolysate. Under the optimized conditions, the correlation coefficients ( r) for the calibration curves were 0.998-0.999 in the range 0.60-12 mol L. The limit of detection was 5.1 μmol kg, and the limit of quantification was 9.2 μmol kg. The recoveries varied from 84 to 97% with RSDs equal to or lower than 11%. The intra-day and inter-day repeatability values, expressed as the relative standard deviation, were less than 8.7 and 9.8, respectively. No obvious matrix effect existed in the different cosmetics matrices. The validated method was applied for the analysis of 57 commercial cosmetic samples. [ABSTRACT FROM AUTHOR]

For the analysis of edible oils, saponification is well known as a useful method for eliminating oil matrices. The conventional approach is conducted with alcoholic alkali; it consumes a large volume of organic solvents and impedes the retrieval of analytes by microextraction. In this study, a low-organic-solvent-consuming method has been developed for the analysis of benzo[a]pyrene in edible oils by high-performance liquid chromatography with fluorescence detection. Sample treatment involves aqueous alkaline saponification, assisted by a phase-transfer catalyst, and selective in situ extraction of the analyte with a supramolecular solvent. Comparison of the chromatograms of the oil extracts obtained by different microextraction methods showed that the supramolecular solvent has a better clean-up effect for the unsaponifiable matter from oil matrices. The method offered excellent linearity over a range of 0.03- 5.0 ng mL−1 ( r > 0.999). Recovery rates varied from 94 to 102% (RSDs <5.0%). The detection limit and quantification limit were 0.06 and 0.19 μg kg−1, respectively. The proposed method was applied for the analysis of 52 edible oils collected online in China; the analyte contents of 23 tested oil samples exceeded the maximum limit of 2 μg kg−1 for benzo[a]pyrene set by the Commission Regulation of the European Union. [ABSTRACT FROM AUTHOR]

Edible oil is easily contaminated with phthalic acid esters (PAEs). Conventional procedures to analyze individual PAEs require very rigorous experimental conditions that are extremely labor-intensive due to significant procedural contaminations generated by the ubiquitous presence of PAEs in the laboratory environment. In this study, a rapid screening method for PAEs in edible oil was successfully developed. Using a phase-transfer catalyst (terabutylammonium bromide) during oil/water biphasic base hydrolysis of PAEs, the hydrolysis time was decreased from a previously reported time of 20 h to 10 min (80 °C). The resulting phthalic acid in the acidified hydrolysate was extracted with 600 μL of tributyl phosphate and then analyzed by high performance liquid chromatography–tandem mass spectrometry in 6 min. Parameters affecting the hydrolysis of PAEs and the extraction of phthalic acid were optimized, and the analytical method was validated. No obvious matrix effect existed in the edible oils whether an external or internal standard method was used. The detection limit was 1.0 μmol kg −1 , and the quantification limit was 1.3 μmol kg −1 . The recovery rates varied from 86 to 107% with relative standard deviations equal to or lower than 9.9% in all of the tested conditions. Twenty-six samples were analyzed, and the background corrected total PAE content was found to be in the range of

Pinoresinol diglucoside (PDG) and pinoresinol (Pin) are normally produced by plant cells via the phenylpropanoid pathway. This study reveals the existence of a related pathway in Phomopsis sp. XP-8, a PDG-producing fungal strain isolated from the bark of the Tu-chung tree (Eucommiaulmoides Oliv.). After addition of 0.15 g/L glucose to Phomopsis sp. XP-8, PDG and Pin formed when phenylalanine, tyrosine, leucine, cinnamic acid, and p-coumaric acid were used as the substrates respectively. No PDG formed in the absence of glucose, but Pin was detected after addition of all these substrates except leucine. In all systems in the presence of glucose, production of PDG and/or Pin and the accumulation of phenylalanine, cinnamic acid, or p-coumaric acid correlated directly with added substrate in a time- and substrate concentration- dependent manner. After analysis of products produced after addition of each substrate, the mass flow sequence for PDG and Pin biosynthesis was defined as: glucose to phenylalanine, phenylalanine to cinnamic acid, then to p-coumaric acid, and finally to Pin or PDG. During the bioconversion, the activities of four key enzymes in the phenylpropanoid pathway were also determined and correlated with accumulation of their corresponding products. PDG production by Phomopsis sp. exhibits greater efficiency and cost effectiveness than the currently-used plant-based system and will pave the way for large scale production of PDG and/or Pin for medical applications. [ABSTRACT FROM AUTHOR]

Pinoresinol diglucoside (PDG) is the important antihypertensive compound in Eucommia ulmoides Oliv., a traditional Chinese herb medicine. The research objective was to certify the possibility of producing PDG through fermentation. PDG-producing endophytic fungi were isolated from E. ulmoides Oliv., and the highest PDG-yielding (11.65 mg/L) isolate, XP-8, was identified as Phomopsis sp. according to the morphological characteristics and the phylogenetic tree constructed on the basis of the gene sequence in the internal transcribed spacers district. The microbial PDG was isolated by using S-8 resin and purified to a purity of 98.7% using preparative high-performance liquid chromatography (HPLC). Information obtained from the UV spectrum (277 and 227 nm, in water solution), infra-red spectrum (3,428; 2,930; 2,877; 1,637; 1,600; and 1,513; 1,460; 1,421; 1,269; 1,223; 1,075; 658 cm, in powder), molecular weight (682 Da, measured using HPLC-electrospray ionization mass spectrometry (ESI/MS) and tandem mass spectrometry), and nuclear magnetic resonance analysis show the microbial PDG is (+)-1-pinoresinol 4,4′-di- O-β- d-glucopyranoside, same as the plant-derived PDG. The microbial PDG is stable in pH range from 3 to 11 but less stable at temperature higher than 90 °C and in light exposure. During the fermentation, PDG production outside cells starts at the later stage of cell growth when the residual sugar in the medium was low. The study reveals the possibility for production of PDG by fermentation. [ABSTRACT FROM AUTHOR]

A selective and low organic‐solvent‐consuming method of sample preparation combined with high‐performance liquid chromatography and tandem mass spectrometry is introduced for phthalate sum analysis in farmland soil. Sample treatment involves a one‐step hydrolysis of phthalates using methanol and alkaline and tetrabutylammonium bromide for 20 min at 80℃. Then, the resulting phthalic acid in the acidified hydrolysate is extracted using an octanol‐based supramolecular solvent without purification. Under optimized conditions, the correlation coefficients were 0.992–0.999 and standard errors (Sy/x) were 0.018–0.138 for calibration curves within the range of 50–2000 ng/mL. No obvious matrix effect occurred between the pure supramolecular solvent and soil extract. The recovery rates ranged from 91 to 107% with the relative standard deviation ranging from 0.5–7.3%. Intra‐ and interday repeatability, expressed as relative standard deviation, was less than 8.0 and 11.0%, respectively. The detected limit was 2.49 nmol/g, and the quantification limit was 3.64 nmol/g. Fifteen soil samples were analysed, and the background corrected phthalate sum ranged from 1.44 to 120 nmol/g. [ABSTRACT FROM AUTHOR]

Acetonitrile stacking is an online concentration method that is distinctive due to its inclusion of a high proportion of organic solvent in sample matrices. We previously designed a universal methodology for the combination of liquid-phase microextraction (LPME) and capillary electrophoresis (CE) using acetonitrile stacking and micellar electrokinetic chromatography (MEKC) mode, thereby achieving large-volume injection of the diluted LPME extractant and the online concentration. In this report, the methodology was extended to the analysis of highly substituted hydrophobic chlorophenols in wines using diethyl carbonate as the extractant. Additionally, the mechanism of acetonitrile stacking was studied. The results indicated that the combination of LPME and MEKC exhibited good analytical performance: with ∼40-fold concentration by LPME, a 20-cm (33% of the total length) sample plug injection of an eight-fold dilution of diethyl carbonate with the organic solvent-saline solution produced enrichments higher by a factor of 260–791. Limits of qualification ranged from 5.5 to 16.0 ng/mL. Acceptable reproducibilities of lower than 1.8% for migration time and 8.6% for peak areas were obtained. A dual stacking mechanism of acetonitrile stacking was revealed, involving transient isotachophoresis plus pH-junction stacking. The latter was associated with a pH shift induced by the presence of acetonitrile. The pseudo-stationary phase (Brij-35) played an important role in reducing the CE running time by weakening the isotachophoretic migration of the analyte ions following Cl − ions. The combination of acetonitrile stacking and nonionic micelle-based MEKC appears to be a perfect match for introducing water-immiscible LPME extractants into an aqueous CE system and can thus significantly expand the application of LPME-CE in green analytical chemistry. [ABSTRACT FROM AUTHOR]

The decrease in the content of higher alcohols and the increase in the ester content in alcoholic drinks are normally achieved by the aging process over years. This study examined the capability of some strains of Geotrichum spp. to complete this process within a few days. Four Geotrichum spp. strains (S12, S13, TM and TF) were separately added to one wine [containing 11.5% (v/v) ethanol] and to three liquor samples [containing 45, 50 and 55% (v/v) ethanol] and incubated at 28 and 15°C for 4 days. Significant increases in the ester content and decreases in the higher alcohols were observed with strains S12 and TM, in all treatments. Strains S13 and TF increased the ester content in the wine, but not in the liquors. Comparatively, most volatile compounds were found in the red wine treated with S12 at 15°C and in the liquor containing 55% (v/v) ethanol treated with TM at 28°C. The conversion from higher alcohols to their corresponding acids and esters was identified using gas chromatography coupled with mass spectrometry during the treatments. By comparing the results when enzyme extracts and whole cells were used, it was found that the decrease in the levels of the higher alcohols might be caused both by cell adsorption and enzymatic reactions, whereas the increase in the esters was caused mainly by enzymatic reactions. Copyright © 2016 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Alicyclobacillus acidoterrestris can survive the pasteurization process, multiply in pasteurized juices and produce guaiacol which causes medicinal or antiseptic off-flavors. Chemical preservatives have the potential to suppress outgrowth of surviving populations during subsequent storage of fruit juices. In the present study, the individual effects of potassium sorbate, sodium benzoate, potassium metabisulfite, dehydroacetic acid, ethyl 4-hydroxybenzoate, cinnamic acid and ε-polylysine on A. acidoterrestris growth and guaiacol production were firstly evaluated in a laboratory medium. Of the seven preservatives investigated, only dehydroacetic acid, cinnamic acid and ε-polylysine were effective both in controlling growth and guaiacol formation by A. acidoterrestris . Then, these three antimicrobials were applied to apple juice. Through the addition of 270 mg/L dehydroacetic acid, 108 mg/L cinnamic acid or 100 mg/L ε-polylysine, the A. acidoterrestris counts were reduced by 3.43, 3.17 and 4.78 log colony forming unit (CFU)/mL, respectively, and no guaiacol was detected after 14 days of storage. Sensory evaluation revealed that the addition of these three preservatives did not affect the organoleptic properties of the apple juice. Results obtained in this paper could be very useful for a better control of A. acidoterrestris -related spoilage in the fruit juice/beverage industry. [ABSTRACT FROM AUTHOR]

Alicyclobacillus acidoterrestris has recently received much attention due to its implication in the spoilage of pasteurized fruit juices, which was manifested by the production of guaiacol. Vanillic acid and vanillin have been accepted as the biochemical precursors of guaiacol in fruit juices. The purpose of this study was to try to find other precursors and elucidate details about the conversion of vanillic acid and vanillin to guaiacol by A . acidoterrestris . Four potential substrates including ferulic acid, catechol, phenylalanine and tyrosine were analyzed, but they could not be metabolized to guaiacol by all the thirty A . acidoterrestris strains tested. Resting cell studies and enzyme assays demonstrated that vanillin was reduced to vanillyl alcohol by NADPH-dependent vanillin reductase and oxidized to vanillic acid by NAD(P) + -dependent vanillin dehydrogenases in A . acidoterrestris DSM 3923. Vanillic acid underwent a nonoxidative decarboxylation to guaiacol. The reversible vanillic acid decarboxylase involved was oxygen insensitive and pyridine nucleotide-independent. [ABSTRACT FROM AUTHOR]

This study established a new method for quantitative and qualitative determination of certain components in black rice wine, a traditional Chinese brewed wine. Specifically, we combined solid-phase extraction and high-performance liquid chromatography (HPLC) with triple quadrupole mass spectrometry (MS/MS) to determine 8 phenolic acids, 3 flavonols, and 4 anthocyanins in black rice wine. First, we clean samples with OASIS HLB cartridges and optimized extraction parameters. Next, we performed separation on a SHIM-PACK XR-ODS column (I.D. 3.0 mm × 75 mm, 2.2 μm particle size) with a gradient elution of 50% aqueous acetonitrile (V/V) and water, both containing 0.2% formic acid. We used multiple-reaction monitoring scanning for quantification, with switching electrospray ion source polarity between positive and negative modes in a single chromatographic run. We detected 15 phenolic compounds properly within 38 min under optimized conditions. Limits of detection ranged from 0.008 to 0.030 mg/L, and average recoveries ranged from 60.8 to 103.1% with relative standard deviation ≤8.6%. We validated the method and found it to be sensitive and reliable for quantifying phenolic compounds in rice wine matrices. [ABSTRACT FROM AUTHOR]

A reliable and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of aflatoxins (AFB1, AFB2, AFG1, and AFG2), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEA), fumonisin B1 (FB1), and T2-toxin in maize. The samples were first extracted using acetonitrile: water: acetic acid (79 : 20 : 1), and then further cleaned-up using OASIS HLB cartridge. Optimum conditions for the extraction and chromatographic separation were investigated. The mean recoveries of mycotoxins in spiked maize ranged from 68.3% to 94.3%. Limits of detection and quantification ranged from 0.01 to 0.64 μg/kg and from 0.03 to 2.12 μg/kg, respectively. The LC-MS/MS method has also been successfully applied to 60 maize samples, which were collected from Shaanxi Province of China. Twenty-four of the total 60 samples (40%) were contaminated with at least 1 of these 9 mycotoxins. Occurrence of mycotoxins were 6.7%, 1.7%, 3.3%, 6.7%, 1.7%, 23.3%, and 3.3% for AFB1, AFB2, OTA, ZEA, DON, FB1, and T2-toxin, respectively. The results demonstrated that the procedure was suitable for the simultaneous determination of these mycotoxins in maize matrix. [ABSTRACT FROM AUTHOR]