The importance, prevalence and determination of vitamins B6 and B12 in food matrices: A review.

Vitamins are a vast group of fundamental organic compounds, which are not produced by the human body but are essential for the living organisms' good health. Vitamins B6 and B12 belong to the same group of hydrophilic vitamins. Structurally unrelated, they share the same purpose as essential components for normal cellular operation, growth and development. Vitamin B6 is an enzymatic co-factor that is vital for countless biochemical reactions, and is also important in sugar and fatty acid metabolization. It encompasses three natural and inter-convertible pyridine-derivatives: pyridoxine, pyridoxal and pyridoxamine. Vitamin B12 is a cobalt organometallic complex also indispensable in numerous human physiological functions. It has four bioactive forms: cyanocobalamin, methylcobalamin, hydroxocobalamin and 5'-deoxyadenosylcobalamin, and only a few prokaryotes have the ability to biosynthesize cobalamin. This work reviews the significant aspects of vitamins B6 and B12: their vital roles, consequences of deficit; food sources; and methods of determination and respective matrices, with heavy emphasis on chromatographic techniques developed within the last two decades.

Content and stability of B complex vitamins in commercial cosmetic products.

BACKGROUND: Individual B vitamins have many favorable effects on the skin and are common cosmetic ingredients. However, their formulation is demanding due to stability issues, which consequently affect the products' quality. AIMS: We aimed to determine the quality (labeling accuracy, content determination, and content-related quality control) and stability under long-term and accelerated storage conditions of a representative sample of commercial cosmetics containing the most common B vitamins - nicotinamide, dexpanthenol, pyridoxine, and cyanocobalamin. METHODS: Cyanocobalamin was determined by a previously published stability-indicating HPLC- diode array detector (DAD) method for the simultaneous determination of all hydrophilic vitamins. This method was additionally simplified and adjusted for the time-effective analysis of nicotinamide, dexpanthenol, and pyridoxine. Both methods were properly validated. RESULTS: All labeled B vitamins were present in the 36 tested products, mostly in contents, reported effective on the skin. Thus, a straightforward correlation between vitamin contents and product prices were not observed. The content-related quality control of eight products, which quantitively specify their content, revealed significantly lower nicotinamide contents (47% and 57%) in two products and appropriate or higher nicotinamide (102%-112%) and dexpanthenol (100%-104%) contents than declared in the remaining products. The 6-month long-term and accelerated stability studies demonstrated the products' physical stability, but also revealed dexpanthenol, pyridoxine, and cyanocobalamin degradation, while nicotinamide was mostly stable in the tested products. CONCLUSIONS: The obtained results provide an inside into the quality of commercial vitamin B cosmetics and highlight the importance of stability testing in the formulation of quality, efficient, and safe cosmetics.

Impurity-profiling UPLC methods for quantitative analysis of some antiemetics formulated with pyridoxine.

Cyclizine hydrochloride (CYC) and meclozine hydrochloride (MEC) are antihistaminic drugs generally co-formulated with pyridoxine hydrochloride (PYR) to treat nausea and vomiting in pregnancy. Several analytical techniques have been applied for the determination of CYC or MEC with PYR, but determination of CYC impurity; benzhydrol (BEH) or MEC impurity; or 4-chlorobenzophenone (BEP) has not been paid attention to. Therefore, micellar UPLC method is introduced for analysis of ternary mixtures containing PYR together with both CYC and BEH (mixture I) or MEC and BEP (mixture II). Chromatographic separation was achieved using a Hypersil gold C8 column (50 × 2.1 mm, 1.9 µm) using 0.01 M sodium dodecyl sulfate modified to pH 3.5 using phosphoric acid:acetonitrile (45:55 by volume) for mixture I and 0.1% sodium dodecyl sulfate, 0.1% sodium bicarbonate adjusted to pH 2.6 by phosphoric acid:acetonitrile (47:53 by volume) for mixture II as mobile phases. The separated peaks were detected at 230 and 245 nm for mixtures I and II, respectively. The adopted methods were validated in conformance with the International Conference on Harmonization (ICH) recommendations and were properly applied in commercial pharmaceutical formulation analysis. Comprehensive ecological comparison was achieved, confirming a higher ecological value of the presented methods compared to the earlier reported methods.

Validation of a quantitative web-based food frequency questionnaire to assess dietary intake in the adult Emirati population.

BACKGROUND AND OBJECTIVE: A culture-specific web-based food frequency questionnaire (FFQ) to assess dietary intake in the United Arab Emirates (UAE) adult population was developed using data from the 2009-2010 national nutrition survey. The objective of this study was to assess the relative validity of the newly developed FFQ for use in the adult Emirati population (AE-FFQ), which contained a list of 139 food lines. METHODS: A convenient sample of 60 (36 females and 24 males) adult Emiratis completed 3 non-consecutive 24HRs over a period of one month, followed by the AE-FFQ, which assessed the intake over the previous month. Relative validity was evaluated by comparing nutrient and food group intakes from the AE-FFQ with the average three 24HRs using Wilcoxon signed-rank tests, Spearman's correlation coefficients (CC), Bland-Altman analysis, and cross-classification. RESULTS: The AE-FFQ overestimated energy and most nutrients and food groups. Bland-Altman analysis showed significant proportional bias between the 2 methods. Deattenuated energy-adjusted Spearman correlation coefficients were poor to good ranging from 0.06 (iron) to 0.62 (fiber) for nutrients, 0.39 median value, and from -0.01 (cruciferous vegetables) to 0.64 (eggs) for food groups, 0.41 median value. A fairly acceptable agreement was obtained, with correct classification into the same or adjacent quartile ranging from 34% (vitamin B12) to 78% (pyridoxine), median 69% for nutrients and from 55% (diet soft drinks) to 87% (soft drinks), median 67% for food groups. CONCLUSIONS: The AE-FFQ is an acceptable tool for ranking UAE adults (aged 18 to 50) according to their dietary intake to investigate the role of Emirati dietary patterns on health and disease. Caution is needed for assessing absolute intake, however, given the bias observed in assessing group-level agreement.

Adoption of Advanced Chemometric Methods for Determination of Pyridoxine HCl, Cyclizine HCl, and Meclizine HCl in the Presence of Related Impurities: A Comparative Study.

BACKGROUND: Noising is an undesirable phenomenon accompanying the development of widely used chemometric models such as partial least square regression (PLSR) and support vector regression (SVR). OBJECTIVE: Optimizations of these chemometric models by applying orthogonal projection to latent structures (OPLS) as a preprocessing step which is characterized by canceling noise is the purpose of this research study. Additionally, a comprehensive comparative study between the developed methods was undertaken highlighting pros and cons. METHODS: OPLS was conducted with PLSR and SVR for quantitative determination of pyridoxine HCl, cyclizine HCl, and meclizine HCl in the presence of their related impurities. The training set was formed from 25 mixtures as there were five mixtures for each compound at each concentration level. Additionally, to check the validity and predictive ability of the developed chemometric models, independent test set mixtures were prepared by repeating the preparation of four mixtures of the training set plus preparation of another four independent mixtures. RESULTS: Upon application of the OPLS processing method, an upswing of the predictive abilities of PLSR and SVR was found. The root-mean-square error of prediction of the test set was the basic benchmark for comparison. CONCLUSION: The major finding from the conducted research is that processing with OPLS reinforces the ability of models to anticipate the future samples. HIGHLIGHTS: Novel optimizations of the widely used chemometric models; application of a comparative study between the suggested methods; application of OPLS preprocessing methods; quantitative determination of pyridoxine HCl, cyclizine HCl and meclizine HCl; checking the predictive power of developed chemometric models; analysis of active ingredients in their pharmaceutical dosage forms.

Nutritional and Functional Evaluation of Inula crithmoides and Mesembryanthemum nodiflorum Grown in Different Salinities for Human Consumption.

The nutritional composition and productivity of halophytes is strongly related to the biotic/abiotic stress to which these extremophile salt tolerant plants are subjected during their cultivation cycle. In this study, two commercial halophyte species (Inula crithmoides and Mesembryanthemum nodiflorum) were cultivated at six levels of salinity using a soilless cultivation system. In this way, it was possible to understand the response mechanisms of these halophytes to salt stress. The relative productivity decreased from the salinities of 110 and 200 mmol L-1 upwards for I. crithmoides and M. nodiflorum, respectively. Nonetheless, the nutritional profile for human consumption remained balanced. In general, I. crithmoides vitamin (B1 and B6) contents were significantly higher than those of M. nodiflorum. For both species, ß-carotene and lutein were induced by salinity, possibly as a response to oxidative stress. Phenolic compounds were more abundant in plants cultivated at lower salinities, while the antioxidant activity increased as a response to salt stress. Sensory characteristics were evaluated by a panel of culinary chefs showing a preference for plants grown at the salt concentration of 350 mmol L-1. In summary, salinity stress was effective in boosting important nutritional components in these species, and the soilless system promotes the sustainable and safe production of halophyte plants for human consumption.

Determination of selected water-soluble vitamins (thiamine, riboflavin, nicotinamide and pyridoxine) from a food matrix using hydrophilic interaction liquid chromatography coupled with mass spectroscopy.

Water-soluble vitamins are essential dietary components with a multitude of important functions that require quantification from food sources to characterise the nutritional status of food. In this study, we have developed a hydrophilic interaction chromatography (HILIC) based method coupled to single-quadrupole mass spectrometry (MS) for the analysis of selected water-soluble vitamins. Due to their involvement in energy release from macronutrients, the quantification of thiamine (B1), riboflavin (B2), nicotinamide (B3) and pyridoxine (B6) offers significant value in food analysis. A commercially available vegetable soup was selected as the food matrix for this study and utilised to develop an efficient extraction procedure for the vitamins of interest. Vitamins were extracted using meta-phosphoric acid coupled with a reducing agent, DL-dithiothreitol (DTT) to produce the parent compound. The extracted vitamins were then analysed using an LC-MS system with electrospray - atmospheric pressure ionization (ES-API) source, operated in positive single ion monitoring (SIM) mode. The MS provided good linearity within the investigated range from 5 to 400 ng/mL with coefficient of determination (r2) ranging from 0.98 to 0.99. Retention times (0.65-9.04 min) were reproducible and no coelution between vitamins was observed. Limit of detection (LOD) varied from 2.4 to 9.0 ng/mL and limit of quantification (LOQ) was from 8 to 30 ng/mL, comparable to previously published studies. The extraction method provided good intra-day (%CV 1.56-6.56) and inter-day precision (%CV 8.07-10.97). Standard injections were used as part of quality control measures and provided excellent reproducibility (%CV 0.9-3.4). The overall runtime of this method was 19 min, including column reconditioning. Using this method, the quantity of thiamine (67 ±â€¯7 ng/g), riboflavin (423 ±â€¯39 ng/g), nicotinamide (856 ±â€¯77 ng/g) and pyridoxine (133 ±â€¯11 ng/g) was determined from a complex food matrix. In conclusion, we have developed a rapid and reliable, HILIC-single quad MS method utilising SIM for the low-level quantification of four B vitamins in a vegetable soup matrix in under 20 min. This method has shown excellent linearity, intra- and inter-day reproducibility and is directly applicable to other plant-based food matrices.

Submerged fermentation of Ginkgo biloba seed powder using Eurotium cristatum for the development of ginkgo seeds fermented products.

BACKGROUND: Ginkgo biloba seeds are well known for the significant curative effects on relieving cough and asthma. However, the development of products from ginkgo seeds still falls behind at present, resulting in a great waste of ginkgo seeds' resource. In this work, submerged fermentation of ginkgo seed powder using Eurotium cristatum was studied to investigate its feasibility as a new processing method. RESULTS: To promote the growth of E. cristatum, the optimum fermentation medium was 80.0 g L-1 of ginkgo seed powder with addition of 5.0 g L-1 calcium chloride (CaCl2 ), 4.0 g L-1 magnesium sulfate (MgSO4 ), 1.25 g L-1 zinc sulfate (ZnSO4 ) and 0.65 g L-1 iron(II) sulfate (FeSO4 ). The optimum fermentation conditions were pH 5.8 ± 0.1, inoculum size 5.1 × 106 CFU mL-1 , liquid medium volume 100 mL in 250-mL Erlenmeyer flask and fermentation 4 days. Through fermentation, the production of lovastatin in fermentation broth could reach up to 32.97 ± 0.17 µg mL-1 and the total antioxidant capacity was improved by more than two-fold. In addition, 40.15% of the ginkgotoxin in ginkgo seed powder was degraded while the entire degradation of ginkgolic acids was obtained. Moreover, fermented ginkgo seed powder suspension presented pleasant fragrances, and the activities of amylase and protease were enhanced to 11.30 ± 0.10 U mL-1 and 23.01 ± 0.20 U mL-1 , respectively. CONCLUSIONS: Submerged fermentation using E. cristatum could significantly enhance the functional value and safety of ginkgo seed powder, and had great potential to become a novel processing method for the development of ginkgo seeds fermented products. © 2020 Society of Chemical Industry.

Effect of different drying methods on product quality, bioactive and toxic components of Ginkgo biloba L. seed.

BACKGROUND: Ginkgo biloba seeds are used as a functional food across Asia. However, the presence of toxic compounds has limited their application. In this study, freeze drying, infrared drying, hot-air drying and pulsed-vacuum drying were used to dry G. biloba seeds. A comprehensive analysis was performed on their product quality, antioxidant activities, bioactive and toxic components. RESULTS: Results showed that the drying methods had a significant influence on product quality with freeze drying being superior due to the minimal microstructural damage, followed by infrared drying and pulsed-vacuum drying. Infrared-dried product possessed the strongest antioxidant activities and higher bioactive compound content than hot-air-dried and pulsed-vacuum-dried product. Toxic compounds in fresh G. biloba seeds (ginkgotoxin, ginkgolic acid and cyanide) were reduced markedly by drying. Ginkgotoxin was reduced fourfold, and the contents of acrylamide, ginkgolic acid and cyanide in dried G. biloba seeds were reduced to the scope of safety. Amongst the four drying methods, infrared drying had the shortest drying time, and its product showed higher quality and bioactive compound content, and stronger antioxidant activities. CONCLUSIONS: These findings will offer salient information for selecting a drying method during the processing of ginkgo seeds. Infrared drying could be considered as a multiple-effect drying method in the processing of ginkgo seeds. © 2020 Society of Chemical Industry.

Relationship between Vitamin Deficiencies and Co-Occurring Symptoms in Autism Spectrum Disorder.

Recently, connections have been made between feeding and eating problems and autism spectrum disorder (ASD) and between autism pathophysiology and diet issues. These could explain some of the mechanisms which have not yet been discovered or are not sufficiently characterized. Moreover, there is an increased awareness for micronutrients in ASD due to the presence of gastrointestinal (GI) problems that can be related to feeding issues. For example, levels of vitamins B1, B6, B12, A and D are often reported to be low in ASD children. Thus, in the present mini review we focused on describing the impact of some vitamins deficiencies and their relevance in ASD patients.

The Use of a Biostimulant Composition to Increase Turkey Viability during the Key Critical Periods of Development.

The paper reports that the treatment of hatching turkey eggs with a mixture composed of colamine, succinic acid, serine, and pyridoxine hydrochloride increased the viability of embryos and reduced incubation wastes. This effect allowed increasing the hatching of turkey poults by 6.73% and the hatchability of eggs, by 4.43%. At the same time, a statistically significant decrease in the key lipid peroxidation products in one-day-old turkey poults was observed. In particular, the content of isolated double bonds decreased 1.47-fold (p < 0.01); diene conjugates, 1.67-fold (p < 0.01); triene conjugates, 1.46-fold (p < 0.05); oxidiene conjugates, 1.48-fold (p < 0.01); and Schiff bases, 1.3-fold compared to the control. All the above-mentioned positively affected survivability in the experimental group, which appeared to be increased by 1% compared to the control.

Targeted healthy compounds in small and large-scale brewed beers.

The determination of targeted healthy compounds in the most popular small and large-scale brewed beer sold in Italy was carried out. Nitrogen compounds, fermentable sugars, total phenolic content and antioxidant capacity, ß-glucans, pyridoxine, folates and silicon were quantified. Further, amine content was determined since raw materials and brewing technology can affect their level. Significantly higher values for total phenolic content, antioxidant activity, nitrogen, folate and putrescine content were found for small scale beers. However, the statistical results were affected by the different beer styles in the small scale and large scale brewed beer groups, since the content of these components can vary between beer styles. Positive Pearson correlation was found between total phenolic content and EBC colour. Wide variations in pyridoxine, ß-glucans and fermentable sugars levels were observed both for small and large scale beers, while average silicon content of two groups was similar.

Cyclodextrin-Modified Micellar UPLC for Direct, Sensitive and Selective Determination of Water Soluble Vitamins in Milk.

Cyclodextrin-modified micellar ultra pressure liquid chromatography (CD-MUPLC) was firstly developed and directly applied to the simultaneous determination of water-soluble vitamins thiamine hydrochloride (VB1), pyridoxine hydrochloride (VB6) and ascorbic acid (VC) in milk samples. A hybrid isocratic mobile phase consisting of ß-cyclodextrin (ß-CD, 5.0 mmol L-1) and cetyltrimethylammonium bromide (CTAB, 0.1 mol L-1) in the presence of acetic acid (0.1 mol L-1) at pH 2.9 on a RP-C18 column at 25.0°C was successfully used. The separation of vitamins was achieved in less than 10 min at a 0.2 mL min-1 flow rate showing adequate linearity at 245 nm in the ranges of 5.0-500.0 µg L-1 for VB1, 5.0-1000.0 µg L-1 for VB6 and 5.0-10000.0 µg L-1 for VC with coefficients of variation (r2) of 0.9999, 0.9987 and 0.9971, respectively. In addition, limits of detection obtained were 0.885, 1.352 and 1.358 µg L-1 and limits of quantification were 2.681, 4.096 and 4.115 µg L-1 for VB1, VB6 and VC, respectively. The high sensitivity of the proposed CD-MUPLC-UV method permitted its applications to the determination of water-soluble vitamins VB1 (32-488 µg L-1), VB6 (82-95 µg L-1) and VC (790-45000 µg L-1) in breast and bovine milk samples. The relative standard deviations and recoveries ranged between 0.07 and 2.14% and between 85.27 and 114.8%, respectively, indicating the accurate and precise measurements without any negative impact of matrix. The current analytical method illustrated several advantages including direct, sensitive, selective and non-consuming organic solvents over the hitherto published methods. These features could be attributed to the four-point competitive interactions among analytes, pseudostationary phases and modified C18 stationary phases.

Hydrogen sulphide production by Saccharomyces cerevisiae UCD 522 in a synthetic grape juice medium deficient of thiamin (vitamin B1 ) and/or pyridoxine (vitamin B6 ).

The impacts of thiamin and pyridoxine along with YAN on alcoholic fermentation and hydrogen sulphide production by Saccharomyces cerevisiae were studied. Using a synthetic grape juice medium, three fermentation trials were conducted; (i) 2 × 3 factorial design with thiamin (0, 0·2, or 0·5 mg l-1 ) and YAN (60 or 250 mg l-1 ) as variables, (ii) 2 × 3 factorial design with pyridoxine (0, 0·25, or 0·5 mg l-1 ) and YAN (60 or 250 mg l-1 ) as variables, and (iii) 3 × 3 factorial design with thiamin (0, 0·2 or 0·5 mg l-1 ) and pyridoxine (0, 0·25 or 0·5 mg l-1 ) as variables in media containing 60 mg l-1 YAN. Although the progress of fermentations was affected by thiamin or pyridoxine, YAN had a larger impact than either vitamin. H2 S production was significantly lower with increasing amounts of thiamin in those fermentations under low YAN (60 mg l-1 ) while even lower amounts (<30 µg l-1 ) were produced under high YAN (250 mg l-1 ) with or without the vitamin. The highest amounts of H2 S were synthesized in those fermentations without any pyridoxine (>110 µg l-1 ), with the lowest production in media with pyridoxine and high YAN (<20 µg l-1 ). SIGNIFICANCE AND IMPACT OF THE STUDY: Concentrations of thiamin, pyridoxine and yeast assimilable nitrogen (YAN) influenced the synthesis of hydrogen sulphide (H2 S) by Saccharomyces cerevisiae in a synthetic grape juice medium. With a few exceptions, an increase in the concentration of either vitamin or YAN resulted in less H2 S released. This is the first report to demonstrate that both thiamin and pyridoxine along with YAN affected H2 S production, emphasizing the need to assess yeast nutrients to lower risks of off-odours during fermentation.

Analysis of the Overlapped Electrochemical Signals of Hydrochlorothiazide and Pyridoxine on the Ethylenediamine-Modified Glassy Carbon Electrode by Use of Chemometrics Methods.

In this work, the electrochemical behavior of hydrochlorothiazide and pyridoxine on the ethylenediamine-modified glassy carbon electrode were investigated by differential pulse voltammetry. In pH 3.4 Britton-Robinson (B-R) buffer solution, both hydrochlorothiazide and pyridoxine had a pair of sensitive irreversible oxidation peaks, that overlapped in the 1.10 V to 1.20 V potential range. Under the optimum experimental conditions, the peak current was linearly related to hydrochlorothiazide and pyridoxine in the concentration range of 0.10-2.0 µg/mL and 0.02-0.40 µg/mL, respectively. Chemometrics methods, including classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS), were introduced to resolve the overlapped signals and determine the two components in mixtures, which avoided the troublesome steps of separation and purification. Finally, the simultaneous determination of the two components in commercial pharmaceuticals was performed with satisfactory results.

Headspace conditions and ingredients can affect artefactual benzene formation in beverages.

A headspace sampling-gas chromatography/mass spectrometry (HS-GC/MS) method using mild HS conditions (40 °C, 30 min) was established, validated in terms of specificity, linearity (1.75-87.65 ng mL-1), precision (0.3-9.1% RSD), and accuracy (81.1-117.7%); and applied for the monitoring of 900 commercial beverage samples of six different types. These mild (low-temperature) conditions were compared with 1) optimized (high-temperature) conditions and 2) a liquid-phase microextraction method involving no heat treatment. This method was desirable because a high equilibrium temperature induced artefactual benzene formation from benzoate and ascorbic acid. In a 2IV8-3 fractional factorial design, eight variables-ascorbic acid, benzoate, benzaldehyde, Cu2+, Fe2+, riboflavin, pyridoxine, and heat treatment-were tested as potential factors affecting benzene formation. All variables except Fe2+ and pyridoxine significantly affected benzene formation, both individually and interactively. The present study suggests an accurate and reliable method for benzene analysis and provides strategies to prevent unintentional benzene formation in beverages.

The effect of UV-protected ethylene vinyl acetate (EVA) bags on the physicochemical stability of pediatric parenteral nutrition admixtures.

BACKGROUND: The safe administration of parenteral admixtures should be considered under the headings of physical and chemical stability. Vitamins are considered to be most susceptible to chemical degradation. OBJECTIVES: To evaluate the protective effect of UV-protected monolayer ethylene vinyl acetate (EVA) bags in comparison with that of EVA bags without UV protection, on the physicochemical characteristics and stability of the light sensitive vitamins in pediatric parenteral admixtures stored under various temperature and light conditions. METHODS: Four different parenteral pediatric admixtures (with trace elements and vitamins) in two types of ethylenovinylacetate (EVA) monolayer containers (with - yellow one and without - transparent one UV protection) were assessed. The physicochemical analyses such as visual inspection, pH and potential zeta measurements, lipid globules size distribution and vitamins concentration were performed at 0 h, 24 h, 8 days and 8 days+24 h after the preparation of the TPN admixtures. In order to quantify ascorbic acid, thiamine and pyridoxine levels, HPLC was used. RESULTS: No differences (p < 0.05) in physicochemical stability of TPN admixtures were noted between two types of EVA bags, with the compositions assessed; stored 8 days (4 °C ± 2) without light plus 24 h at room temperature and light exposure. However significant differences were noticed in ascorbic acid, thiamine and pyridoxine content after 8 days+24 h in comparison with t = 0. This was noted for both for UV-protected bags and bags without UV-protection, Nevertheless, amounts were still within the pharmacopeial range. CONCLUSIONS: Both EVA bags under test (with and without UV-protection) ensure physicochemical stability up 8 days at 4 °C ± 2 °C without light exposure and then 24 h at room temperature with light exposure for the total pediatric parenteral admixtures, intended for home parenteral nutrition. Graphical abstract Scheme of physicochemical analysis of parenteral admixtures.

Rapid identification of herbal toxins using electrospray laser desorption ionization mass spectrometry for emergency care.

The unintentional ingestion of toxic compounds in herbs is not uncommon in many parts of the world. To provide timely and life-saving care in the emergency department, it is essential to develop a point-of-care analytical method that can rapidly identify these toxins in herbs. Since electrospray laser desorption ionization mass spectrometry (ELDI/MS) has been successfully used to characterize non-volatile chemical compounds without sample preparation, it was used to identify toxic herbal compounds in this study. The herbal toxins were collected either by sweeping a metallic probe across the surface of a freshly cut herb section or by directly sampling extracts of ground herbal powder. The analytes on the probe were then desorbed, ionized and detected using ELDI/MS, wherein analysis of the herbal toxins was completed within 30 s. This approach allows for the rapid morphological recognition of herbs and early point-of-care identification of herbal toxins for emergency management and is promising in providing important toxicological information to ensure appropriate medical treatment.

A short-term stimulation of ethanol enhances the effect of magnetite on anaerobic digestion.

Conductive iron oxides (CIO) have been proved recently to facilitate the anaerobic microbial syntrophy based on the direct interspecies electron transfer (DIET) in batch experiments. However, the effect of CIO was always insignificant in anaerobic digestion (AD) reactor especially when the DIET-based syntrophic partners were absent. In this study, the effect of magnetite on performance of AD system with sucrose as a sole carbon source was investigated, but limited enhancement was achieved during the first 36-day operation. The short-term effect of ethanol addition was further studied in the magnetite-amended AD reactor, and results showed that the AD reactor with 10gFe/L micro-sized magnetite (R3) achieved higher performance of COD removal and methane proportion compared with the other reactors (R1 without magnetite; R2 with 2gFe/L micro-sized magnetite; R4 with 2gFe/L nano-sized magnetite). Meanwhile, the pyridoxine in extracellular polymeric substances (EPS) and conductivity of anaerobic sludge from R3 increased more significantly than those of the others. Analysis of high-throughput sequencing indicated that the abundance of archaea increased in sludge from R3 and Methanosarcina responsible for DIET was dominant (63.64%). Additionally, the abundance of potential electroactive bacteria Chloroflexi in R3 was 7.57-fold, 3.61-fold and 7.37-fold as that of R1, R2 and R4, respectively. These results demonstrated that the electroactive microbes and methanogens could be enriched efficiently in anaerobic sludge via synergetic effect of magnetite addition and ethanol short-term stimulation.

H-point standard addition for simultaneous reagent-free spectrophotometric determination of B1 and B6 vitamins.

Vitamin deficiency is a main cause of many disorders and diseases that cannot be treated without using dietary supplements and multivitamin medications. We present here a UV-spectrophotometric method for simultaneous assay of two of the widely used vitamins, thiamine hydrochloride (vitamin B1) and pyridoxine hydrochloride (vitamin B6). The method is based on H-point standard addition to estimate the vitamins under study in their pure solutions and multivitamin ampoules by measuring the absorption of the mixture at 283 and 298 nm allowing its application in quality control laboratories. The work summarizes the theoretical basis of the H-point standard addition method. Moreover, a guide for the selection of the two wavelengths at which the calibration curves are constructed is given in this investigation. The linear ranges of the calibration graphs are 6.75-67.5 and 2.06-20.56 µg/mL for thiamine and pyridoxine, respectively. Correlation coefficients (r2) were found to be 0.9990 and 0.9899 at 283 nm and 0.9855 and 0.9995 at 298 nm for vitamin B1 and vitamin B6, respectively. Oscillator strength (f), transition dipole moment (µ) and resonance energy (RN) were calculated. The method was successfully applied for dual determination of the vitamins in their pure solutions and multivitamin ampoules with recovery values ranging from 98.41 to 102.6 and from 95.39 to 104.9% for thiamine and pyridoxine, respectively. The accuracy and precision of the proposed method is obvious from the low relative standard deviation values which are not more than 1.19%.