Determination of process contaminants 2- and 3-MCPD esters and glycidyl esters in palm-based glycerol by indirect analysis using GC-MS.

Esters of 2- and 3-monochloropropanediol (2-MCPDE, 3-MCPDE) and glycidol (GE) are regarded as process contaminants that are found in refined vegetable oils and oil-based foods. Since glycerol is produced during fat splitting, saponification and biodiesel production, it is important to have methods for determining contaminants that might be formed during these processes. Due to the use of glycerol as a food additive, data on the presence of compounds of toxicological concern, including 3-MCPD, are of interest. This study focuses on modifying the indirect analysis of 2-MCPDE, 3-MCPDE and GE using GC-MS based on the AOCS Official Method Cd 29a-13, validating the modified method, and quantifying 2-MCPDE, 3-MCPDE and GE in glycerol. The AOCS Cd 29a-13 method was modified at the initial stage of sample preparation in which the targeted esters were extracted from glycerol by vortex-assisted extraction before sample analysis. This modification was performed based on the polarity of all compounds involved. The calibration functions for all analytes were fitted to linear regression with R2 above 0.99. Limits of detection (LOD) 0.02, 0.01 and 0.02 mg kg-1 were obtained for 2-MCPDE, 3-MCPDE and GE, respectively. Spiked glycerol with 3-MCPDE and 2-MCPDE (0.25, 0.51 and 1.01 mg kg-1) and GE (0.58, 1.16 and 2.32 mg kg-1) were used for recovery and precision measurements. Recoveries of 100-108%, 101-103%, and 93-99% were obtained for 2-MCPDE, 3-MCPDE and GE, respectively. Acceptable precision levels with relative standard deviations ranged from 3.3% to 8.3% were obtained for repeatability and intermediate precision. The validated method was successfully applied for the analysis of the target compounds in refined glycerol from commercial plants, which showed that 2-MCPDE, 3-MCPDE and GE levels in the analysed samples were below the detection limit.

Occurrence and risk assessment of 3-monochloropropanediols esters (3-MCPDE), 2-monochloropropanediol esters (2-MCPDE), and glycidyl esters (GE) in commercial infant formula samples from Malaysia.

The presence of 3-monochloropropanediol esters (3-MCPDE), 2-monochloropropanediol esters (2-MCPDE) and glycidyl esters (GE) in infant formula products has raised serious concerns. They incorporate vegetable oils, particularly palm-based oils, which are well-known to contain large amounts of these process contaminants. An analysis was conducted on infant formula samples (n = 16) obtained from the Malaysian market to determine the levels of 3-MCPDE, 2-MCPDE and GE using gas chromatography-mass spectrometry (GC-MS). The method was validated, with a limit of quantification (LOQ) on instrument of 0.10 µg/g for all analytes. The median concentrations of 3-MCPDE, 2-MCPDE and GE in infant formula in this study were 0.008 µg/g, 0.003 µg/g and 0.002 µg/g respectively. The estimated dietary intakes calculated from consumption of infant formula show higher exposures to infants within the age group of 0 to 5 months, highest for GE (1.61 µg/kg bw/day), followed by 3-MCPDE (0.68 µg/kg bw/day) and 2-MCPDE (0.41 µg/kg bw/day) compared to the age group of 6 to 12 months. Only one sample, relating to GE exposure is a potential risk for both age groups with MOE value below 25,000.

Valorization of Amaranth (Amaranthus cruentus) Grain Extracts for the Development of Alginate-Based Active Films.

This research work investigates the development of alginate-based films incorporating phenolic compounds extracted from Amaranthus cruentus grain using different solvents. Alginate, glycerol, and amaranth grain phenolic compounds at various concentrations were used to produce the films. An experimental Central Composite Rotatable Design (CCRD) was used to evaluate the effect of these variables on different film's properties, i.e., water vapor permeability, hydrophobicity, moisture content, solubility, thermal, mechanical, and optical properties. This study demonstrated that high phenolic compound content and antioxidant capacity were obtained from amaranth grain using ethanol as the extraction solvent. Alginate films incorporating amaranth phenolic compounds were successfully manufactured, and this study can be used to tailor the formulation of alginate films containing amaranth phenolic compounds, depending on their final food application. For example, less flexible but more resistant and water-soluble films can be produced by increasing the alginate concentration, which was confirmed by a Principal Component Analysis (PCA) and Partial Least Squares (PLS) analysis. This study showed that active alginate films with amaranth phenolic compounds can be tailored to be used as food packaging material with potential antioxidant activity.

Preparation and characterization of micro/nanocellulose reinforced PVDF/wood composites.

Polyvinylidene fluoride (PVDF) is commonly used in the chemical, electronic, and petrochemical industries because of its chemical and physical attributes. This study aimed to make novel PVDF-based composite with a high loading of silanized wood powder and micro/nanocellulose fibers, where glycerol acts as both a dispersant and a plasticizer all-in-one composite application for the first time. The purpose was also extended to systematically investigate their mechanical properties and melt flow. Results have demonstrated the efficiency of utilizing the cellulose fibers in bio-composites. With the addition of 30 wt% of filling materials, When the content of silanized cellulose fibers in glycerol dispersion is 25 wt%, the flexural strength and tensile strength reach the maximum value 72.30 MPa and 52.28 MPa. The experimental results indicate that silanized micro/nanocellulose fiber-reinforced PVDF/wood composites are a promising composite formula to help improve performance and reduce costs. It is an excellent example of utilizing biomass resources as a renewable/recyclable, sustainable and low-cost material to reduce the use of petroleum-based polymer, and improve the mechanical properties of composites.

Occurrence of 2- and 3-monochloropropanediol esters (MCPDE) in infant formula products on the Canadian market between 2015 and 2019.

2- and 3-monochloropropanediol esters (MCPDEs) are most commonly formed as process-induced contaminants during the refinement of vegetable oils used for food production. 'In vivo' hydrolysis of 3-MCPDEs releases the potential carcinogen 3-monochloropropanediol (3-MCPD). Levels of MCPDEs in infant formula are of particular concern, as refined oils are commonly used as main fat ingredients. For this study, infant formula samples (powders, liquid concentrates and ready-to-feed infant formula samples) from the Canadian market were purchased and analysed in 2015 (35 samples) and 2019 (33 samples). MCPDE concentrations (expressed as free MCPD equivalents) were examined through an indirect analytical approach, applying acid-catalysed ester cleavage and using cyclohexanone as derivatising agent. Labelled diesters were used as internal standards. 2015 Survey data were analysed by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring mode (SIM). 2019 Survey data were analysed with an updated method using GC-MS/MS in multiple reaction monitoring modes (MRM). In 2015, levels in reconstituted formula ranging from 3.7 ng/g to 111 ng/g for 3-MCPD and 2.2 ng/g to 56.2 ng/g for 2-MCPD were found. In 2019, levels ranging from 3.9 ng/g to 74.8 ng/g for 3-MCPD and 1.0 ng/g to 33.9 ng/g for 2-MCPD were found. A significantly reduced mean of combined MCPDEs was observed between 2015 and 2019 data (64.5 ng/g, standard deviation (SD) 8.6 ng/g in 2015 to 31.8 ng/g, SD 5.6 ng/g in 2019, p-value = 0.024). For the majority of manufacturers, the data comparison among brand products over time shows decreased levels of MCPDEs. Occurrence data of MCPDEs, including data from previously published surveys (2012/2013), were also compared and a temporal trend was established.

Determination of glycidyl esters and 3-MCPD esters in edible oils by sample pretreatment with the combination of lipase hydrolysis and modified QuEChERS for GC-MS analysis.

Glycidyl esters (GEs) and 3-chloroprapane-1,2-diol esters (3-MCPDEs) are processing contaminants in refined edible oils that have raised concerns globally owing to their potentially carcinogenic properties. Official analytical methods for GEs and 3-MCPDEs, such as AOCS Cd 29a-13 and AOCS Cd 29b-13, require up to 16 h for chemical hydrolysis. Also, parallel experiments should be conducted to correct for the conversion of analytes during hydrolysis in AOCS Cd 29b-13. For AOCS Cd 29c-13 with the shortest operating time, the reaction time (3.5-5.5 min) and temperature of alkaline hydrolysis should be carefully controlled, implying the accuracy may be influenced by human errors. Here, we propose a novel method based on Candida rugosa lipase hydrolysis and direct detection of free form GEs, glycidol, which was achieved by sample preparation with modified QuEChERS, to prevent side reactions in previous approaches, and also to shorten the overall sample preparation time. Glycidol was directly analyzed without halogenation and derivatization, whereas 3-MCPD required derivatization for analysis by GC-MS. Our method showed good accuracy and precision in terms of repeatability, intermediate precision, and reproducibility (inter-laboratory precision). The limit of detection (LOD) and limit of quantification (LOQ) for glycidol were 0.02 and 0.1 mg/kg, which is sufficient for practical applications. The proposed method was further compared with AOCS Cd 29c-13 by determination of GEs content in commercial oil samples and spiked samples. Our method with a streamlined procedure seems to possess potential advantage of reduced errors from operational factors. This proposed method based on direct detection of glycidol may serve as a simplified alternative for routine analysis of GEs and 3-MCPDEs in edible oils.

Quality assessment of refined red palm-pressed mesocarp olein.

Palm-pressed mesocarp oil has been found to contain plenty of naturally occurring valuable phytonutrients. The application and study of the oil are limited, therefore, quality assessment of refined red palm-pressed mesocarp olein (PPMO) is deemed necessary to provide data in widening the applications as a niche products or raw material for the nutraceutical industry. Results showed that refined PPMO has comparable physicochemical properties and oxidative stability with commercial cooking oil, palm olein (PO). The food safety parameters and contaminants (PAH, 3-MCPD ester, 2-MCPD ester, glycidyl ester and trace metals) analyses proven that refined PPMO is safe to be consumed. Besides, refined PPMO contains remarkably greater concentrations of phytonutrients including carotenoids, phytosterols, squalene and vitamin E than PO, postulating its protective health benefits. The overall quality assessment of refined PPMO showed that it is suitable for human consumption and it is a good source for food applications and dietary nutritional supplements.

Monochloropropanediol esters and glycidyl esters in dietary supplements based on fish oils.

Dietary supplements based on fish oils might be contaminated with thermal processing contaminants, which are generated during the fish oil deodorisation. In the study, 30 samples of dietary supplements were analysed in terms of the occurrence of 3-monochloropropane-1,2-diol esters (3-MCPDE), 2-monochloropropane-1,3-diol esters (2-MCPDE) and glycidyl esters (GE). The results showed that the highest levels of 3-MCPDE (mean: 1461 µg kg-1) as well as 2-MCPDE (mean: 357 µg kg-1) were observed in the products containing shark liver oil. In the case of GE, they were mainly detected in the supplements including shark liver and cod liver oils. Although the results indicated that the consumption of the investigated supplements constituted no more than 1% of tolerable daily intake (TDI), the occurrence of MCPDE and GE in fish oil dietary supplements with a special attention to the origin of ester precursors should be thoroughly investigated in further studies.

Occurrence and risk assessment of 3- and 2-monochloropropanediol (MCPD) esters in vegetable oils and related products from Zhejiang market.

3- And 2-monochloropropanediol fatty acid esters (3- and 2-MCPD esters) are contaminants of processed vegetable oils. In this study, vegetable oils and related products available 486 food samples from Zhejiang market were collected and analysed for 3- and 2-MCPD esters during 2016-2018. Food consumption data were taken from a food consumption survey of urban and rural residents in Zhejiang province performed in 2008 using data from 9646 subjects. Levels of 3-MCPD esters in foods ranged from not detected to 8.3 mg/kg, and the highest mean levels were found in vegetable oils with levels of 0.76 mg/kg. Esters of 2-MCPD levels ranged from not detected to 4.0 mg/kg, and the highest mean levels were found in instant noodles containing 0.40 mg/kg. The dietary intake of 3-MCPD was 0.62 µg/kg bw per day (mean) and 2.29 µg/kg bw per day (P97.5), and 2-MCPD esters intakes were 0.26 µg/kg bw per day (mean) and 0.87 µg/kg bw per day (P97.5). Vegetable oils were the main food source of dietary 3- and 2-MCPD esters intake. These findings suggested that the dietary exposure levels of 3-MCPD esters may pose a potential risk to the health for high consumers (P97.5) aged 4-17 when compared to the tolerable daily intake.

Selection of yeasts from bee products for alcoholic beverage production.

The use of appropriate yeast strains allows to better control the fermentation during beverage production. Bee products, especially of stingless bees, are poorly explored as sources of fermenting microorganisms. In this work, yeasts were isolated from honey and pollen from Tetragonisca angustula (Jataí), Nannotrigona testaceicornis (Iraí), Frieseomelitta varia (Marmelada), and honey of Apis mellifera bees and screened according to morphology, growth, and alcohol production. Bee products showed to be potential sources of fermenting microorganisms. From 55 isolates, one was identified as Papiliotrema flavescens, two Rhodotorula mucilaginosa, five Saccharomyces cerevisiae, and nine Starmerella meliponinorum. The S. cerevisiae strains were able to produce ethanol and glycerol at pH 4.0-8.0 and temperature of 10-30 °C, with low or none production of undesirable compounds, such as acetic acid and methanol. These strains are suitable for the production of bioethanol and alcoholic beverages due to their high ethanol production, similar or superior to the commercial strain, and in a broad range of conditions like as 50% (m/v) glucose, 10% (v/v) ethanol, or 500 mg L-1 of sodium metabisulfite.

[Alkaline transesterification CG-MS/MS method of monochlorpropanediol and glycidyl esters' determination in some edible fats, oils and fat blends on Russian market].

Monochlorpropanediol fatty acid esters (MCPDE) and glycidyl fatty acid esters (GE) are mainly considered to be processing contaminants and their concentration can rise during high temperature refining and deodorization of edible oils. Free forms formed during digestive hydrolysis of esters such as 3-monochloropropane-1,2-diol (3-MCPD), 2-MCPD and glycidol can provoke a negative effect on human health. Therefore the quantitative determination of MCPDE and GE in edible oils, fats and fat blends is needed. The aim - this manuscript deals with MCPDE and GE concentration measured as free 3-MCPD, 2-MCPD and glycidol in different edible oils, fats and fat blends of Russian market. Material and methods. 55 edible oil and fat samples sold on Russian market including refined and non-refined oils and fat blends such as spreads, dairy fat replacers, and margarines have been analyzed. Slow alkaline transesterification method with GC-MS/MS was used. Results. According to the data obtained, the highest concentrations of the contaminants were detected in fat blends: <0.10-5.03 mg/kg for 3-MCPD, <0.10-2.50 mg/kg for 2-MCPD and 0.1 5-11.17 mg/kg for glycidol. In palm oils and its fractions concentration of 3-MCPD was <0.10-6.61 mg/kg, 2-MCPD - <0.10-2.69 mg/kg and glycidol - <0.10-6.29 mg/kg. The content of glycidol in sunflower oils fluctuated in the range <0.10-1.19 mg/kg, 3-MCPD was <0.10-2.47 mg/kg, and 2-MCPD <0.10-0.67 mg/kg. Non-refined edible oils and olive oils had no or little MCPDE or GE. Conclusion. In this work we indicate high importance of monitoring MCPDE and GE in edible oils and fats both as ready-to-eat products and as ingredients prior to the Russian market release. There is strong need in mitigation of these process contaminants during fat blends manufacturing.

Verification and evaluation of monochloropropanediol (MCPD) esters and glycidyl esters in palm oil products of different regions in Malaysia.

This study was conducted to investigate on the effect of different sampling regions of palm-refined oils and fats on the 2- and 3-monochloropropanediol fatty acid esters (MCPDE) and glycidol fatty acid esters (GE) levels. The American Oil Chemists' Society (AOCS) Official Method Cd 29a-13 on the determination of MCPDE and GE in edible oils and fats by acid transesterification was successfully verified and optimised, with slight modification using 7890A Agilent GC system equipped with 5975C quadrupole detector. The determined limits of detection (LOD) for MCPDE were 0.02 mg kg-1 and 0.05 mg kg-1 for GE. The method performance has showed good recovery between 80% and 120% for all pertinent compounds with seven replicates assayed in three separate days. Round robin test with two European laboratories, i.e. Eurofins and SGS, has shown compliance results with those of the present study. Among the sampling regions, only one refinery located in the central region of Malaysia showed a significant increment of the MCPDE and GE levels after refining process. The GE level averaging at 2.5 mg kg-1 was slightly higher than that of 3-MCPDE averaging at 1.3 mg kg-1. Both esters were preferentially partitioned into the liquid phase rather than the solid phase after fractionation. However, the overall results exhibited no direct correlation between the esters content and the different sampling locations of the palm oil products in Malaysia. Analysis of total chlorine content also displayed significant variations between sampling locations which clearly show its effect on the chlorine content in the CPO samples.

Dietary oils modify lipid molecules and nutritional value of fillet in Nile tilapia: A deep lipidomics analysis.

The nutritional value of fish fillet can be largely affected by dietary oils. However, little is known about how dietary oils modify lipid molecules in fish fillets. Through biochemical and lipidomics assays, this study demonstrated the molecular characteristics of fillet lipids in Nile tilapia fed with different oils for six weeks. High 18:2n-6 and low 18:3n-3 deposition in phosphoglycerides resulted high 18:2n-6/18:3n-3 ratio in tilapia. Dietary n-3 VLCUFAs intake increased its deposition at sn-1/3 of triglycerides and at sn-2 of phosphatidylcholines. Irrespective of dietary oil, 16:0 was distributed preferentially at the outer positions of glycerol backbone. High 18:2n-6 accumulated at sn-2 position for fish fed with n-3 PUFA-enriched oils. High 18:3n-3 deposited at sn-1/3 in TG, sn-1 in phosphatidylethanolamines, while at sn-2 in phosphatidylcholines. Together, dietary oils change the composition and positional distribution of fatty acids on the glycerol backbone, and change nutritional value of fish for human health.

Effect of soybean oil availabilities on rumen biohydrogenation and duodenal flow of fatty acids in beef cattle fed a diet with crude glycerine.

Soybean oil with different ruminal availability (whole soybeans (WS), soybean oil (SO) and calcium salts (CS)) was used to evaluate the fatty acid (FA) intake, rumen biohydrogenation (BH) and duodenal flow of FA in Nellore steers fed diets with crude glycerine (CG). Eight castrated Nellore steers were fitted with a ruminal and duodenal silicone cannula, and distributed in a double, simultaneous, Latin square 4 × 4 design with four diets and four experimental periods. Concentrates contained ground maize, urea, mineral salts, CG (100 g/kg DM) and soybean products with different availability of soybean oil: (1) no additional fat (CO), (2) WS, (3) SO or (4) CS. Fat supplementation was fixed to obtain 50 g ether extract/kg DM. Experimental treatments had no effect on DM intake, DM duodenal flow or ruminal turnover rate of C:16 FA. However, fat addition increased C:18 and turnover rates of total FA rumen (p < 0.05). CS resulted in lower C:18 turnover rates and lower ruminal BH of monounsaturated and unsaturated FA (UFA) than WS (p < 0.05). SO resulted in a greater duodenal flow of C18:0 (stearic acid), C18:1t-11 (vaccenic acid) and saturated FA than the WS and CS diets (p < 0.05). CS resulted in a higher duodenal flow of C18:3n-3 (linolenic acid) than WS (p < 0.05). The association of CG and calcium salts in Nellore steers was the best nutritional strategy to increase duodenal flow of healthier UFA, which may increase the deposition of these FA in meat. However, SO associated with CG association increased the duodenal flow of vaccenic acid, which is main precursor of endogenous synthesis of conjugated linoleic acids in tissues.

Toxicity of Natural Deep Eutectic Solvent Betaine:Glycerol in Rats.

Natural deep eutectic solvents (NaDES) are new natural solvents in green chemistry that in some cases have been shown to allow better extraction of plant bioactive molecules compared to conventional solvents and higher phenolic compound absorption in rodents. However, there is a serious lack of information regarding their in vivo safety. The purpose of this study was to verify the safety of a NaDES (betaine:glycerol (1:2 mole ratio) of water) extract from green coffee beans, rich in polyphenols. Twelve 6-week-old male Wistar rats were randomized into two groups of 6 animals each and twice daily gavaged for 14 days either with 3 mL of water or 3 mL of phenolic NaDES extract. Oral administration of phenolic NaDES extract induced mortality in two rats. In addition, it induced excessive water consumption, reduced dietary intake and weight loss, hepatomegaly, and plasma oxidative stress associated with high blood lipid levels. In conclusion, this work demonstrated the toxicity of oral administration of the selected NaDES under a short-term condition. This occurs despite the fact that this NaDES extract contains polyphenols, whose beneficial effects have been shown. Therefore, complementary work is needed to find the best dose and formulation of NaDES that are safe for the environment and animals and ultimately for humans.

Bioactive Compounds in Cornelian Cherry Vinegars.

We analyzed the effect of Cornelian cherry varieties differing in fruit color ('Yantaryi'-yellow fruits, 'Koralovyi'-coral fruits, 'Podolski'-red fruits) and the production method on the physicochemical and antioxidative properties of Cornelian cherry vinegars, and on their content of iridoids and polyphenols. Acetic fermentation was conducted by two methods: I) single-stage (spontaneous) acetic fermentation, without inoculation with microorganisms, and II) two-stage fermentation in which the first stage involved the use of Saccharomyces bayanus-Safspirit fruit yeast for alcoholic fermentation, and the second one included spontaneous acetic fermentation. Acetic acid, glycerol, individual iridoids, phenolic acids, flavonols, and anthocyanins were quantified by a high-performance liquid chromatography (HPLC) method. The antioxidative activity was determined based on the following tests: 2,2-Diphenyl-2-picryl-hydrazyl (DPPH•), 2,2'-Azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS•+), and ferric reducing antioxidant power (FRAP), while the total polyphenols content was determined using the Folin-Ciocialteu (F-C) reagent test. Both the Cornelian cherry variety and vinegar production method affected the antioxidative properties as well as concentrations of iridoids and polyphenols in the finished product. The concentration of total polyphenols (F-C) in vinegars ranged from 326.60 to 757.27 mg gallic acids equivalents (GAE)/100 mL vinegar, whereas the antioxidative activity assayed with the DPPH• and FRAP methods was the highest in the vinegars produced from the coral and red varieties of Cornelian cherry with the two-stage method. Loganic acid predominated among the identified iridoids, reaching a concentration of 185.07 mg loganic acid (LA)/100 mL in the vinegar produced in the two-stage fermentation from the coral-fruit variety. Caffeoylquinic acid derivatives were the main representatives among the identified phenolic compounds. The results of this study demonstrate Cornelian cherry vinegars to be rich sources of biologically-active iridoids and phenolic compounds with antioxidative properties.

Effect of acetate to glycerol ratio on enhanced biological phosphorus removal.

Enhanced biological phosphorus removal (EBPR) is a sustainable and promising technology for phosphorus removal from wastewater. The efficiency of this technology, however, is often discounted due to the insufficient carbon sources in influent. In this work, the effect of acetate to glycerol ratio on the EBPR performance was evaluated. The experimental results showed when the ratio of acetate to glycerol decreased from 100/0% to 50/50%, the EBPR efficiency increased from 90.2% to 96.2%. Further decrease of acetate to glycerol ratio to 0/100% decreased the efficiency of EBPR to 30.5%. Fluorescence in situ hybridization analysis demonstrated appropriate increase of glycerol benefited to increase the relative abundance of phosphate accumulating organisms. Further investigation revealed the proper addition of glycerol increased the amount of polyhydroxyalkanoates synthesis, and then produced sufficient energy for oxic luxury phosphorus in the subsequent oxic phase.

Discrimination of processing grades of olive oil and other vegetable oils by monochloropropanediol esters and glycidyl esters.

In this study, the processing derived contaminants 2- and 3-monochloropropanediol (2- and 3-MCPD) esters and glycidyl esters (GEs) were analysed in 84 oil samples by GC-MS/MS for the discrimination of processing grades of olive oils as a potential authentication tool. Concentrations of 2- and 3-MCPD esters and GEs varied in the ranges 0-6 mg/kg, 0-1.5 mg/kg, and 0-1 mg/kg oil, respectively. The concentrations of the three compounds in lower grade olive oils were significantly higher (P < .001) than that in EVOO. A similar difference was observed for other refined and cold-pressed vegetable oils. The limit of fraud detection of lower grade oils in EVOO was 2% when using 3-MCPD esters, 5% for 2-MCPD esters, and 13-14% for GEs based on calculations of virtual mixtures of the current sample set. Especially the MCPD esters appear very specific and promising for the detection of lower processing grade oils in EVOO.

Hyperbaric oxygen therapy may overcome nitric oxide blockage during cyanide intoxication.

PURPOSE: To determine the effects of a blockade of nitric oxide (NO) synthesis on hyperbaric oxygen (HBO2) therapy during cyanide (CN) intoxication. METHODS: 39 anesthetized female Sprague-Dawley rats were exposed to CN intoxication (5.4 mg/kg intra-arterially) with or without previous nitric oxide synthase (NOS) inhibition by L-NG-nitroarginine methyl ester (L-NAME) injection (40 mg/kg intraperitoneally). Subsequently, either HBO2 therapy (284 kPa/90 minutes), normobaric oxygen therapy (100% oxygen/90 minutes) or nothing was administered. Intracerebral microdialysis was used to measure the interstitial brain concentration of lactate, glucose, glycerol and lactate/pyruvate ratios. RESULTS: L-NAME potentiated CN intoxication by higher maximum and prolonged lactate (in mM: 0. 5 ± 0.3 vs. 0.7 ± 0.4, P ⟨ 0.005) concentrations compared with solely CN-intoxicated rats. The same trend was found for mean glucose, glycerol and lactate/pyruvate ratio levels. During HBO2 treatment a sustained reduction occurred in mean lactate levels (in mM: 0.5 ± 0.5 vs. 0.7 ± 0.4, P ⟨ 0.01) regardless of NOS blockade by L-NAME. The same trend was found for mean glucose and glycerol levels. CONCLUSION: The results suggest that blocking NOS using L-NAME can worsen acute CN intoxication. HBO2 treatment can partially overcome this block and continue to ameliorate CN intoxication.

Benefits of ion mobility for analysing monochloropropane-diol esters.

This paper reports the first application and benefits of ion mobility in combination with liquid chromatography and a transportable time-of-flight mass spectrometer to the analysis of monochloropropane-diol esters (MCPDE) in vegetable oils. The additional selectivity obtained with the ion mobility allowed the quantitative analysis of MCPDEs as such in their intact form (direct analysis) without any chemical derivatisation and, furthermore, without any enrichment or purification step. This gain in selectivity manifests primarily in the resolution of interferences originating, for example, from the diacylglycerol components of palm oil. In silico calculations confirm that resolution of such interferences would require mass resolutions higher than 200,000 at m/z 600, e.g., in the case of signals of the 41K isotope of the PO DAG and the signals of the sodiated PO MCPD. While such resolution can be obtained on certain state-of-the-art costly and laboratory-exhaustive research instruments, this study demonstrates that even transportable time-of-flight MS can achieve the required selectivity when combined with ion mobility. Further advantage of the described approach is that the applied sample preparation is only dilution with minimum consumable requirements and can be performed quickly even outside laboratories directly in the field. The described results suggest that the application of ion mobility in addition to LC-MS is likely to push the boundaries of contaminant analysis especially for high-throughput screening investigations.