A highly sensitive determination method for acrylamide in beverages, grains, and confectioneries by supercritical fluid chromatography tandem mass spectrometry

Acrylamide: An approach to its knowledge and importance for roasted coffee

Acrylamide (AA) has been classified as a toxic, harmful, and carcinogenic substance since 2002, and therefore it is currently widely studied. When functional amino and carbonyl groups of asparagine and reducing sugars are condensed into Schiff bases, they are transformed into AA molecules at temperatures >120 °C. This mechanism is known as the Maillard reaction and is considered the main AA pathway. Simultaneously, desired browning and sensory properties are developed. However, changes in chemical composition of the matrix, properties, and secondary reactions trigger intermediary synthesis, destabilizing the medium and leading to new AA molecules. Coffee has become the most consumed beverage worldwide. Therefore, the World Health Organization established recommended benchmark levels of AA concentrations that could be detected in roasted coffee beans and by-products (<850 μg/kg). Trace levels of AA can differ between samples due to roasting and brewing conditions, and the analytical and extraction methods chosen for sample analysis.

Toxicity, formation, contamination, determination and mitigation of acrylamide in thermally processed plant-based foods and herbal medicines: A review

Thermal processing is one of the important techniques for most of the plant-based food and herb medicines before consumption and application in order to meet the specific requirement. The plant and herbs are rich in amino acids and reducing sugars, and thermal processing may lead to Maillard reaction, resulting as a high risk of acrylamide pollution. Acrylamide, an organic pollutant that can be absorbed by the body through the respiratory tract, digestive tract, skin and mucous membranes, has potential carcinogenicity, neurological, genetic, reproductive and developmental toxicity. Therefore, it is significant to conduct pollution determination and risk assessment for quality assurance and security of medication. This review demonstrates state-of-the-art research of acrylamide focusing on the toxicity, formation, contamination, determination, and mitigation in taking food and herb medicine, to provide reference for scientific processing and ensure the security of consumers.

Understanding the mechanism of CO2-Assisted electrospray ionization for parameter optimization in supercritical fluid chromatography mass spectrometry

Supercritical fluid chromatography (SFC) is often coupled with electrospray ionization mass spectrometry (ESI-MS) for analyte detection because of its detection capability to a wide range of chemical properties. However, MS sensitivity is highly dependent on the chromatographic conditions, so that it is important to understand the ionization mechanism to determine the optimal chromatographic conditions. The ionization mechanism in SFC/ESI-MS is different to that of liquid chromatography because of the use of CO₂ as a mobile phase. Some studies have suggested that alkoxycarbonic acids are formed in the mixture of CO₂ and the alcohol modifier, and these species contribute to ionization in CO₂-assisted SFC/ESI-MS. Therefore, in this study, we investigated CO₂-assisted ESI to test this hypothesis, and we confirmed that methoxylcarbonic acid is generated in CO₂/methanol mixtures and contributed to ion generation and detection because it acts as a proton donor in positive-ion mode. However, methoxylcarbonic acid interfered with ionization in negative-ion mode. Addition of ammonium acetate, which is often added to the modifier for negative ion detection in SFC/MS analysis, did not contribute to the recovery of MS sensitivity, although it tended to suppress the formation of metoxylcarbonic acid. This is likely due to ion suppression and neutralization of the negative sites of the analytes by anions or cations derived from ammonium acetate in the negative ion mode. Thus, additive-free methanol/CO₂ was the most suitable mobile phase for obtaining high sensitivity in SFC/MS. To demonstrate the practicality of these findings, we tested our optimal mobile phase selection for pesticide analysis. In addition, we tested the addition of 0, 1, and 5 mM ammonium formate to the modifier and make-up solvent, and found that the addition of 1 mM ammonium formate gave the best results in pesticides analysis. In SFC/MS, salt is often added to improve separation or prevent desorption, but our findings suggest that the concentration of salt must be kept as low as possible to achieve highly sensitive MS detection. The results of this study reveal the best selection of the optimal conditions for the modifier and make-up solvent for CO₂-assisted SFC/MS analysis and will be useful for the method development in SFC/MS.

Simultaneous Determination of Six Immunosuppressants in Human Whole Blood by HPLC-MS/MS Using a Modified QuEChERS Method

A high-performance liquid chromatography-tandem mass spectrometry method was established for the simultaneous determination of mycophenolic acid, mycophenolate mofetil, tacrolimus, rapamycin, everolimus and pimecrolimus in human whole blood by optimizing the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) preparation method. Whole blood was extracted into ethyl acetate, salted out with anhydrous magnesium sulfate, and purified with ethylenediamine-N-propyl silane adsorbent. The supernatant was evaporated under nitrogen until dry and finally reconstituted in methanol. Chromatographic separation was performed on an Agilent Poroshell 120 EC-C18 column in methanol (mobile phase A)-water (optimized for 0.1% acetic acid and 10 mM ammonium acetate, mobile phase B) at a 0.3 mL·min−1 flow rate. Electrospray ionization and positive ion multiple reaction monitoring were used for detection. The time for of analysis was 13 min. The calibration curves range of tacrolimus, rapamycin, everolimus and pimecrolimus were in the range of 1−100 ng·mL−1, mycophenolate mofetil in the range of 0.1−10 ng·mL−1 and mycophenolic acid at 10−1000 ng·mL−1. All correlation coefficients were >0.993. The coefficients of variation (CV, %) for inter-day and intra-day precision were less than 10%, while the spiked recoveries were in the range of 92.1% to 116%. Our method was rapid, sensitive, specific, and reproducible for the simultaneous determination of six immunosuppressants in human whole blood. Importantly, our approach can be used to monitor drug concentrations in the blood to facilitate disease treatment.

A rapid and environmentally friendly method for determination of parabens preservatives in flavors by supercritical fluid chromatography tandem mass spectrometry

A rapid method for determination of parabens preservatives (methyl paraben, ethyl paraben, isopropyl paraben, propyl paraben, isobutyl paraben, and butyl paraben) in flavors was established by using supercritical fluid chromatography tandem mass spectrometry combined with dispersive solid phase extraction. After adding methanol and primary secondary amine to the sample simultaneously, high extraction efficiency and good sample cleanup could be obtained by simple shaking. Parabens were well separated on a Chiralpak IG-3 column in 6 min by gradient elution. Recoveries from spiked blank samples at 0.5, 1.0, and 5.0 mg/kg were determined to be 88.3-106.6%with relative standard deviations less than 8.0%. All analytes achieved good linear relation (r≥0.999 2). The limits of detection for all analytes ranged from 0.03 to 0.09 mg/kg and the limits of quantification from 0.11 to 0.31 mg/kg, respectively. A total of 20 actual samples were successfully analyzed by taking the proposed method. Being simple, rapid, green and reliable, this method can be taken for the determination of parabens preservatives in flavors. This article is protected by copyright. All rights reserved.

A novel single step solid-phase extraction combined with bromine derivatization method for rapid determination of acrylamide in coffee and its products by stable isotope dilution ultra-performance liquid chromatography tandem triple quadrupole electrospray ionization mass spectrometry

This work aimed to establish a novel determination method for acrylamide in coffee and its products by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Acrylamide in samples were prepared by a single-step solid-phase extraction clean-up using mixed mode sorbents. The bromine derivatization efficiency of acrylamide and its internal standard were improved at an acidic condition. After derivation, the retention capability of acrylamide and its resistance to interference were significantly improved. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.2 and 4 μg/kg for roasted and instant coffees, while they were 0.24 and 0.8 μg/kg for ready-to-drink coffees. The average recoveries for acrylamide ranged from 99.3 to 102.2% in coffee and its products. All the results showed that the developed method was simple, quick, specific and suitable for screening and determination of acrylamide in batch samples of coffee and its products.

Towards a consensus LC-MS/MS method for the determination of acrylamide in food that prevents overestimation due to interferences

Acrylamide is prone to misquantification, and critical steps in the analytical procedures need to be identified and controlled to ensure a reliable determination. Four methods were considered to illustrate misquantification issues with acrylamide. For two methods varying by the extent of their sample preparations, cases of overestimation in cocoa samples reaching up to a 20-fold factor are shown. A second example, applied to a variety of food products, includes two other methods varying by their chromatographic conditions. As a follow up of a study conducted in 2020 about the identification of N-acetyl-ß-alanine as an interference of acrylamide in coffee, the extent of this interference was evaluated in a selection of coffee samples, cereal-based products and baby foods. The ultimate objective of this manuscript was to resolve such cases of misquantification and validate a wide scope and robust method allowing an interference free acrylamide analysis. To do so, an extraction procedure based on the EN 16618:2015 standard with water extraction and two consecutive solid phase extraction (SPE) steps was applied with modified liquid chromatographic conditions. The method was validated in coffee, cereals, baby foods, cocoa and pet foods with excellent performance in terms of recovery (97-108%) and precision (RSD_r and RSD_iR <12 %). The breath of scope was further proved through trueness determination in quality control materials and reference materials including French fries, potato crisps, vegetable crisps, instant coffee, infant food and biscuit (cookie), with trueness values found within a 94-107% range.

Analysis of acrylamide in vegetable chips after derivatization with 2-mercaptobenzoic acid by liquid chromatography–mass spectrometry

Since many years, acrylamide (AA) is a well-known toxicologically relevant processing contaminant (“food-borne toxicant”). However, only during the recent years, high levels of acrylamide have been reported in vegetable chips. In the present study, AA was quantitated via a modified derivatization procedure with 2-mercaptobenzoic acid based on stable isotope dilution analysis and liquid chromatography–mass spectrometry. Extraction with a modified QuEChERS (quick, easy, cheap, efficient, rugged, safe) method, defatting with n-hexane, and a solid phase extraction clean-up with strong cation-exchange material were performed prior to the derivatization step. Limits of detection and quantitation (LoD and LoQ) were 12 and 41 µg of AA/kg of vegetable chips (estimated via signal-to-noise ratios of 3:1 and 10:1, respectively), and thus below the LoQ of 50 µg/kg requested by the European Food Safety Authority. Recovery rates between 92 and 101% at four spiking levels with a good precision expressed as a relative standard deviation  < 7% were determined. With this method at hand, a survey of the current AA amounts in 38 vegetable chips from the worldwide market was performed, showing a remarkable variability between the different vegetables, but also between different products of the same vegetable. Thereby, the AA amounts ranged between 77.3 and 3090 µg/kg, with an average of 954 µg/kg which was distinctly higher in comparison to commercially available potato chips also analyzed in the present study (12 samples, range: 117–832 µg/kg, average: 449 µg/kg). While for sweet potato and parsnip relatively low AA amounts were found, beetroot and carrot showed rather high contents.

Development of an Isotope Dilution UHPLC-QqQ-MS/MS-Based Method for Simultaneous Determination of Typical Advanced Glycation End Products and Acrylamide in Baked and Fried Foods

In this work, a stable isotope dilution ultrahigh-performance liquid chromatography triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) method was developed and validated for simultaneous determination of N^ε-(carboxymethyl)lysine (CML), N^ε-(carboxyethyl)lysine (CEL), and acrylamide (AA) in baked and fried foods. Ground food samples were extracted with acetone followed by two parallel assays. In assay A, a cleanup procedure based on dispersive solid-phase extraction was conducted for AA, free CML, and CEL analysis using the supernatant. In assay B, a multistep process including reduction, protein precipitation, acid hydrolysis, and solid-phase extraction was conducted for bound CML and CEL analysis using precipitation. The developed method was validated in terms of linearity, sensitivity (limit of detection, LOD; limit of quantitation, LOQ), accuracy, and precision. The results showed that the method had a wide linear range (0.25-500 ng/mL for CML and CEL, 0.5-500 ng/mL for AA), low LOD and LOQ (0.47-0.94 and 1.52-1.91 μg/kg, respectively), and good linearity (R² > 0.999). The recovery test on baby biscuit and French fries samples showed the recovery rates of 90.2-108.3% for CML, 89.0-106.1% for CEL, and 94.5-112.3% for AA with satisfactory precision (relative standard deviation (RSD) < 10%). Finally, the developed method was successfully applied to 11 baked and fried food samples, and total CML, CEL, and AA contents varied in the ranges of 4.07-35.88 mg/kg, 1.99-14.49 mg/kg, and 5.56-506.64 μg/kg, respectively. Therefore, the isotope dilution UHPLC-QqQ-MS/MS method developed herein is promising for routine analysis of CML, CEL, and AA in baked and fried foods.

Determination and risk assessment of acrylamide in thermally processed Atractylodis Macrocephalae Rhizoma

As one of the medicine homologous foods in China, Atractylodis Macrocephalae Rhizoma (AMR) is usually distributed after thermal processing, which raised the possibility of acrylamide pollution and a potential carcinogenic risk. In this study, a method was developed for the determination of the acrylamide in AMR using graphited multiwalled carbon nanotubes as the dispersive solid phase extraction sorbent and liquid chromatography tandem mass spectrometry. The concentration of acrylamide was investigated at processing conditions of 80℃-210℃ and 5 min-100 min. Method validation results demonstrated the reliability of the method with good linearity, accuracy and precision. Significant increment of acrylamide was found in AMR after thermal processing with the highest concentration at 9826 μg/kg, which led to a margin of exposure at 90.83-181.7 according to the BMDL₁₀ of carcinogenicity at 0.17 mg/kg, indicating a high health risk of taking thermally processed AMR, and monitoring and controlling should be considered.

Study on the stereoselective behaviors of fosthiazate stereoisomers in legume vegetables by supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS)

A separation and analysis method of fosthiazate stereoisomers was established utilizing supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) with a CHIRALPAK AD-3 column. The determination of the four fosthiazate stereoisomers could be completed within 6 min. The environmental behaviors of fosthiazate stereoisomers were studied in legume vegetables. After applying fosthiazate granules to soil, the concentrations of fosthiazate stereoisomers in the legume vegetables increased with time, reached maximum values in 7-10 days, and then decreased gradually in all legumes except for in Glycine max. No obvious dissipation behaviors were observed in Glycine max. Interestingly, the stereoselective behaviors were species-specific. A-(-), B-(-) and B-(±)-fosthiazate were preferentially enriched in Phaseolus vulgaris Linn and Vigna unguiculata, while A-(+) and A-(±)-fosthiazate preferentially accumulated in Vicia faba Linn, Pisum sativum Linn and G. max. The opposite stereoselectivity of B-(±)-fosthiazate was observed in different growth stage of G. max. No stereoselective dissipation occurred in soil.

Supercritical fluid chromatography - Mass spectrometry in metabolomics: Past, present, and future perspectives

Metabolomics, which consists of the comprehensive analysis of metabolites within a biological system, has been playing a growing role in the implementation of personalized medicine in modern healthcare. A wide range of analytical approaches are used in metabolomics, notably mass spectrometry (MS) combined to liquid chromatography (LC), gas chromatography (GC), or capillary electrophoresis (CE). However, none of these methods enable a comprehensive analysis of the metabolome, due to its extreme complexity and the large differences in physico-chemical properties between metabolite classes. In this context, supercritical fluid chromatography (SFC) represents a promising alternative approach to improve the metabolome coverage, while further increasing the analysis throughput. SFC, which uses supercritical CO₂ as mobile phase, leads to numerous advantages such as improved kinetic performance and lower environmental impact. This chromatographic technique has gained a significant interest since the introduction of advanced instrumentation, together with the introduction of dedicated interfaces for hyphenating SFC to MS. Moreover, new developments in SFC column chemistry (including sub-2 µm particles), as well as the use of large amounts of organic modifiers and additives in the CO₂-based mobile phase, significantly extended the application range of SFC, enabling the simultaneous analysis of a large diversity of metabolites. Over the last years, several applications have been reported in metabolomics using SFC-MS - from lipophilic compounds, such as steroids and other lipids, to highly polar compounds, such as carbohydrates, amino acids, or nucleosides. With all these advantages, SFC-MS is promised to a bright future in the field of metabolomics.

Review of Research into the Determination of Acrylamide in Foods

Acrylamide (AA) is produced by high-temperature processing of high carbohydrate foods, such as frying and baking, and has been proved to be carcinogenic. Because of its potential carcinogenicity, it is very important to detect the content of AA in foods. In this paper, the conventional instrumental analysis methods of AA in food and the new rapid immunoassay and sensor detection are reviewed, and the advantages and disadvantages of various analysis technologies are compared, in order to provide new ideas for the development of more efficient and practical analysis methods and detection equipment.

Identification of Acrylamide Adducts Generated during Storage of Canned Milk Coffee

Since coffee is a significant contributor to the consumption of acrylamide, its reduction is required. Acrylamide is produced during the roasting of coffee beans, but the roasting process is an essential step in determining the taste of coffee. Acrylamide content in coffee has been suggested to decrease by reacting with proteins and/or other substances during storage, but details are unknown. Investigation of acrylamide adducts may contribute to a strategy for acrylamide reduction in coffee. In this study, a stable isotope labeling technique, combined with high-resolution mass spectrometry, allows the identification of acrylamide adducts (3-hydroxypyridine-acrylamide and pyridine-acrylamide) in canned milk coffee. Other acrylamide adducts derived from milk coffee proteins, Lys-acrylic acid and CysSO₂-acrylic acid, were identified. During a 4-month storage period, the formation of these four adducts was found to reduce the total content of acrylamide by 75.3% in canned milk coffee. Therefore, endogenous proteins can be used in acrylamide reduction.