Comparison assessment between SIM and MRM mode in the analysis of 3-MCPD ester, 2-MCPD ester and glycidyl ester

Gas chromatography mass spectrometer determination of dimethylamine impurity in N,N-dimethylformamide solvent by derivatization of N,N-dimethylbenzamide with benzoyl chloride agent

This study describes the development of a reliable and linear analytical method for precisely determining dimethylamine impurity in N,N-dimethylformamide solvent utilizing a benzoyl chloride derivatization reagent and a gas chromatography mass spectrometer. Benzoyl chloride was used to derivatize dimethylamine. At normal temperature, benzoyl chloride combined with dimethylamine, producing N,N-dimethylbenzamide. This method separated N,N-dimethylbenzamide using Rtx-5 amine (30 m × 0.32 mm × 1.50 μm) as the stationary phase, helium as the carrier gas, argon as the collision gas, and methanol as the diluent. The column flow rate was 2 mL/min. The retention time of N,N-dimethylbenzamide was determined to be 8.5 min. Precision, linearity, and accuracy were tested using ICH Q2 (R2) and USP<1225> guidelines. The percentage coefficient of variation (CV) for N,N-dimethylbenzamide in the system suitability parameter was 1.1%. The correlation coefficient of N,N-dimethylbenzamide was found to be >0.99. In the method precision parameter, the % CV for N,N-dimethylbenzamide was found to be 1.9%, whereas the % CV for N,N-dimethylbenzamide was 1.2% in intermediate precision. The percentage recovery of N,N-dimethylbenzamide was determined to be between 80% and 98%.

Determination of glycidyl fatty acid esters in edible vegetable oils by HPLC-ESI-QQQ-MS/MS combined with cryo-degreasing tandem dispersive solid-phase extraction

Glycidyl fatty acid esters (GEs) have been identified as food contaminants that can form during the processing and heating of edible oils. Their widespread occurrence raises potential concerns for consumers. This study aimed to develop a simple and effective analytical method for molecular recognition using mass spectrometry fragmentation patterns. Furthermore, it sought to simultaneously and quantitatively determine five common GEs in highly complex fatty matrices (oils) using high-performance liquid chromatography-triple quadrupole tandem mass spectrometry (HPLC-ESI-QQQ-MS/MS). An extraction method using acetonitrile was used, and the purification of the extract was optimized using cryo-degreasing-tandem dispersive solid-phase extraction (d-SPE) to eliminate fatty interferents. The method validation yielded recoveries ranging from 81.17% to 109.28% and the method precision was < 10.00%. The limits of quantification ranged from 0.08 to 0.21 ng/g, which is below the current legal limits. This approach may play a crucial role in ensuring food safety.

3-Monochloropropane-1,2-diol reduced bioaccessibility of sn-2 palmitate via binding with pancreatic lipase in infant formula during gastrointestinal digestion

Infant formula contains 3-monochloropropane-1,2-diol esters (3-MCPDE), which are formed during the deodorization step of vegetable oil refining. The European Food Safety Authority stated that 3-MCPDE can be hydrolyzed in the gastrointestinal tract to free-form 3-monochloropropane-1,2-diol (3-MCPD), which has potential toxicity and can be rapidly absorbed. Evaluating the effect of 3-MCPD on nutrition absorption is a prerequisite for establishing effective management strategies. A total of 66 crucial lipid molecules associated with 3-MCPD were identified based on debiased sparse partial correlation analysis. 3-MCPD affected triglyceride hydrolyzation and increased the concentration of undigested sn-2 palmitate (9.57 to 17.06 mg kg-1). 3-Monochloropropane-1,2-diol reduced the bioaccessibility of fatty acids, and more short- (31.42 to 58.02 mg kg-1) and medium-chain fatty acids (17.03 to 26.43 mg kg-1) remained unabsorbed. Lipidomic profiles of infant formula models spiked with different 3-MCPDE levels were investigated, and the results were consistent with the experiments with the commercial formula indicating lipid alteration was mainly affected by the digestive 3-MCPD. The formation of 3-MCPD ester-pancreatic lipase with the binding energy of -4.9 kcal mol-1 was more stable than triglyceride-pancreatic lipase (-4.0 kcal mol-1), affecting triglyceride hydrolyzation. 3-Monochloropropane-1,2-diol was bound to Glu13 and Asp331 residues of the pancreatic lipase via hydrogen bonds, which resulted in a conformational change of pancreatic lipase and spatial shielding effect. The existence of the spatial-shielding effect reduced the accessibility of pancreatic lipase and further affected triglyceride hydrolyzation. These findings indicated that 3-MCPD obstructed nutrient acquisition and laid the foundation for the subsequent nutrition enhancement design.

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.

Development of a QuEChERS method for simultaneous analysis of 3-Monochloropropane-1,2-diol monoesters and Glycidyl esters in edible oils and margarine by LC-APCI-MS/MS

A simple, fast and effective direct method based on HPLC-APCI-QqQ-MS/MS has been developed to simultaneously determine four 3-monochloropropane-1,2-diol monoesters (3-MCPDE) esterified with palmitic, linoleic, stearic, and oleic acid, and two glycidyl esters (GE) with palmitic and oleic acid in margarine and olive oil using a QuEChERS approach. Factors affecting the efficiency of the extraction process were assessed, including type and amount of salt, extraction solvent, test portion amount, and clean-up sorbent. The analytical method was validated according to Food and Drug Administration (FDA) guidelines using matrix-matched calibration with internal standards and showed good results in terms of linearity (r² > 0.9992), accuracy (80<Recovery<120%), and precision (RSD<15%). The method was successfully applied for the first time to 11 margarine samples for simultaneous analysis of 3-MCPDE and GE.

Methods, principles, challenges, and perspectives of determining chloropropanols and their esters

Chloropropanols and their esters are a group of food contaminants that have various toxicities to the human body. Research and control to chloropropanols and their esters is important to food safety. Therefore, the sensitive, accurate, precise, and effective determination of chloropropanols and their esters is highly essential to study their concentration, formation, and mitigation. The indirect method, commonly applied in the determination of chloropropanols and their esters, is based on the cleavage of ester bond, extraction, and derivatization. The conventional indirect method will still be the mostly used method in the near future due to its good sensitivity and feasibility, although its parameters need to be chosen and optimized according to sample stuffs and chloropropanol concentrations. Meanwhile, direct method and other quantitative methods should also be developed for special applications, such as studying the profile of chloropropanol esters and rapid screening protocol. The challenges and future perspectives of these methods are discussed in this review. This review can provide a reference on the selection, designation, and modification of methods for determining chloropropanols and their esters.

A chemometric strategy to automatically screen selected ion monitoring ions for gas chromatography-mass spectrometry-based pseudotargeted metabolomics

The pseudotargeted metabolomics based on gas chromatography-mass spectrometry (GC-MS) has the advantage of filtering out artifacts originating from sample treatment and accurately quantifying underlying compounds in the analyzed samples. However, this technique faces the problem of selecting high-quality selective ions for performing selected ion monitoring (SIM) on instruments. In this work, we proposed AntDAS-SIMOpt, an automatic untargeted strategy for SIM ion optimization that was accomplished on the basis of an experimental design combined with advanced chemometric algorithms. First, a group of diluted quality control samples was used to screen underlying compounds in samples automatically. Ions in each of the resolved mass spectrum were then evaluated by using the developed algorithms to identify the SIM ion. A Matlab graphical user interface (GUI) was designed to facilitate routine analysis, which can be obtained from http://www.pmdb.org.cn/antdassimopt. The performance of the developed strategy was comprehensively investigated by using standard and complex plant datasets. Results indicated that AntDAS-SIMOpt may be useful for GC-MS-based metabolomics.

Dietary advanced glycation end-products, 2-monochloropropane-1,3-diol esters and 3-monochloropropane-1,2-diol esters and glycidyl esters in infant formulas: Occurrence, formulation and processing effects, mitigation strategies

Infant formula contains thermal processing contaminants, such as dietary advanced glycation end-products (dAGEs), glycidyl esters (GEs), 2-monochloropropane-1,3-diol esters and 3-monochloropropane-1,2-diol esters (MCPDEs). This systematic review aimed to gain insights into the occurrence of these contaminants in different types of infant formula, to understand potential effects of the formulation and processing of infant formulas on these contaminants, as well as into possible mitigation strategies. The occurrence of dAGEs in infant formula depends on the recipes and processing conditions. Hydrolyzed protein formulations promote dAGEs formation in infant formula since peptides are more prone to glycation than intact proteins, which is reflected in high dAGEs concentration in hypoallergenic infant formula. Different carbohydrates in recipes result into different glycation extents of infant formula: maltodextrin containing formulas contained less dAGEs than those with lactose. Concerning mitigation strategies, applying ultra-high-temperature (UHT) treatment during milk processing leads to less dAGEs formation than using in-bottle sterilization. Although data are limited, evidence showed that encapsulation of raw ingredients or the use of antioxidants or enzymes in recipes is promising. The occurrence of MCPDEs and GEs in infant formula fully depends on the vegetable oils used in the recipe. High levels of these contaminants can be found when relatively high amounts of palm oils or fats are used. The mitigation of MCPDEs and GEs should therefore be performed on fats and oils before their application to infant formula recipes. Data and knowledge gaps identified in this review can be useful to guide future studies.

A summary of 2-, 3-MCPD esters and glycidyl ester occurrence during frying and baking processes

Monochloropropanediol (MCPD) esters and glycidyl esters (GE) are the process contaminants found in frying and baking, except the refining process. The free form MCPD and glycidol are released from their parent esters via lipase hydrolysis while they are carcinogen and genotoxic carcinogen, respectively. MCPD esters and GE are formed endogenously during vegetable oil refining process. Then, their concentration were experimented during subsequent food processing methods, especially frying and baking. This review discussed the occurrence of 2-, 3-MCPD esters and GE during frying and baking processes. Process temperature, process duration, presence of precursors, and their combined effects are highly related to MCPD esters and GE formations. An elevated temperature and processing time can increase the formation of these contaminants until an optimum rate and then followed by the decomposition. Also, other factors such as the presence of chloride ions, moisture, and partial acylglycerol can further facilitate MCPD esters and/or GE formation.

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Frying and baking trigger formation of MCPD esters and GE.

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MCPD esters and GE are formed endogenously during refining process.

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The concentration of MCPD esters and GE elevated during thermal processing.

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Temperature, process duration, and precursors cause MCPD esters and GE formations.

Pharmacokinetic studies of ginsenosides Rk1 and Rg5 in rats by UFLC-MS/MS

A rapid ultra-fast liquid chromatography tandem mass spectrometry method was developed and validated to determine ginsenosides Rk1 and Rg5, a pair of isomers, in rat plasma, which was successfully applied to their pharmacokinetic studies. Two ginsenosides were given to male Sprague-Dawley rats via intragastrical and intravenous routes, respectively, and the impact of double bond position on the pharmacokinetic features of the two ginsenosides was elucidated in rats. Ginsenoside Rg3 was used as internal standard and ethyl acetate was applied to extract analytes and internal standard. Chromatographic separation was carried out on a reverse-phase UPLC HSS T3 column (100 × 2.1 mm, 1.8 μm). The flow rate was set to 0.4 ml/min. The fragmentation transition was m/z 765.4 → m/z 101.1 for two ginsenosides. The mobile phases were composed of 0.1% formic acid aqueous solution and acetonitrile. The linear range was 2-1,000 ng/ml for the two ginsenosides. Intra- and inter-day precisions were <11.67%, and accuracy fluctuated from -7.44 to 6.78%. The extraction recovery, matrix effect and stability were within acceptable levels. After treatment with ginsenosides Rk1 and Rg5, some differences were found in their pharmacokinetic profiles in rats. The maximum plasma drug concentration and the area under the plasma drug concentration-time curve of ginsenoside Rg5 were about 5 times bigger than those of ginsenoside Rk1 after oral administration, and 3 times higher after intravenous administration. The oral bioavailabilities of ginsenosides Rk1 and Rg5 were 0.67 and 0.97%, respectively. The results indicated that ∆²⁰⁽²²⁾ -ginsenosides showed better pharmacokinetic features than ∆²⁰⁽²¹⁾ -ginsenosides with the same glycosylation.

Current Progresses on Monochloropropane Diol Esters in 2018-2019 and Their Future Research Trends

The fatty acid esters of monochloropropane diol (MCPD) are a group of food source contaminants formed during thermal processing. These components were recognized as potential food source toxicants in the past few decades, and growing evidence has proven their toxic effects, especially to kidneys and testes. Therefore, increasing research articles reported their results about MCPD esters in recent years. In this perspective, a total of 35 research articles/reviews about MCPD esters, including the studies concerning the analytical methods, occurrences, toxicity, formation mechanism, and mitigation strategies of MCPD esters in 2018-2019 have been summarized and discussed. Updating the latest research results about MCPD esters could improve our understandings about these components, especially on the toxic effects and the mitigation approaches in both academia and industry.

Changes in 3-, 2-Monochloropropandiol and Glycidyl Esters during a Conventional Baking System with Addition of Antioxidants

Shortening derived from palm oil is widely used in baking applications. However, palm oil and the related products are reported to contain high levels of monochloropropandiol (MCPD) ester and glycidyl ester (GE). MCPD and glycidol are known as process contaminants, which are carcinogenic and genotoxic compounds, respectively. The objective was to evaluate the effects of antioxidant addition in palm olein and stearin to the content of MCPD esters and GE in baked cake. Butylated hydroxyanisole (BHA), rosemary extract and tocopherol were used to fortify the samples at 200 mg/kg and in combinations (400, 600 and 800 mg/kg rosemary or tocopherol combined with 200 mg/kg BHA). The MCPD esters and GE content, radical formation and the quality of the fats portion were analyzed. The results showed that palm olein fortified with rosemary extract yielded less 2-MCPD ester. The GE content was lower when soft stearin was fortified with rosemary. ESR spectrometry measurements showed that the antioxidants were effective to reduce radical formation. The synergistic effects of combining antioxidants controlled the contaminants formation. In conclusion, oxidation stability was comparable either in the single or combined antioxidants. Tocopherol in combination with BHA was more effective in controlling the MCPD esters and GE formation.