Solid phase “on-situ” quadraplex isotope dimethyl labeling for the analysis of biogenic amines in beers by liquid chromatography-high resolution mass spectrometry

The Measurement of Hazardous Biogenic Amines in Non-Alcoholic Beers: Efficient and Applicable Miniaturized Electro-Membrane Extraction Joined to Gas Chromatography-Mass Spectrometry

The determination of biogenic amines (BAs) as serious food contaminants and chemical indicators of unwanted microbial contamination or deficient processing conditions in non-alcoholic beers is of great interest for the beverage industries. In the present investigation, the combination of hollow fiber-electro-membrane extraction (HF-EME) and dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC/MS) was applied for the analysis of histamine, putrescine, tyramine, cadaverine in non-alcoholic beers. EME is fundamentally based on the electrostatic attraction, diffusion and solvability of analytes in a selected acceptor phase. This membrane-based extraction technique promoted selectivity and the enrichment factor. The DLLME process reduced the volumes of organic solvents and make the coupling of HF-EME to the CG/MS conceivable. The leading variables, which have a great effect on extraction recovery, were optimized. The relative standard deviation was achieved between 4.9 and 7.0%. The recoveries were between 94% and 98%. The limit of detection and limit of quantification were found to be 0.92-0.98 ng mL^-1 and 3.03-3.23 ng mL^-1, respectively. The enrichment factor was calculated in the range 36-41. The achievements revealed that putrescine and tyramine, with concentrations of 3.87 and 2.33 µg g^-1, were at the highest concentration in non-alcoholic beers. This offered method with great benefits could help beverage industries to monitor the concentration of BAs in beers and control them.

Magnetic Molecularly Imprinted Nano-Conjugates for Effective Extraction of Food Components-A Model Study of Tyramine Determination in Craft Beers

In this paper, magnetic molecularly imprinted nano-conjugates were synthesized to serve as selective sorbents in a model study of tyramine determination in craft beer samples. The molecularly imprinted sorbent was characterized in terms of morphology, structure, and composition. The magnetic dispersive solid phase extraction protocol was developed and combined with liquid chromatography coupled with mass spectrometry to determine tyramine. Ten samples of craft beers were analyzed using a validated method, revealing tyramine concentrations in the range between 0.303 and 126.5 mg L-1. Tyramine limits of detection and quantification were 0.033 mg L-1 and 0.075 mg L-1, respectively. Therefore, the fabricated molecularly imprinted magnetic nano-conjugates with a fast magnetic responsivity and desirable adsorption performance could be an effective tool for monitoring tyramine levels in beverages.

Unmodified cellulose filter paper, a sustainable and affordable sorbent for the isolation of biogenic amines from beer samples

While current trends in Green Analytical Chemistry aim at reducing or simplifying sample treatment, food usually comprises complex matrices where direct analysis is not possible in most cases. In this context, sample treatment plays a pivotal role. Biogenic amines are naturally formed in many foodstuffs due to the action of microorganisms, while their presence has been associated with adverse health effects. In this work, the extraction of seven biogenic amines (cadaverine, histamine, phenylethylamine, putrescine, spermidine, spermine, and tyramine) from beer samples has been simplified using laboratory filter paper as sorbent without any further modification. The analysis of the eluates by direct infusion mass spectrometry reduces the time of analysis, increasing the sample throughput. This simple but effective method enabled the determination of the analytes with limits of detection as low as 0.06 mg L^-1 and relative standard deviations better than 11.9%. The suitability of the method has been assessed by analyzing eight different types of beers by the standard addition method.

Determination of phenolic compounds in estuary water and sediment by solid-phase isotope dansylation coupled with liquid chromatography-high resolution mass spectrometry

A method consisting of solid-phase isotope dansylation (derivatization with dansyl chloride) and liquid chromatography-high resolution mass spectrometry (LC-HRMS) was developed for the quantitative analysis of phenolic compounds (phenols) in environmental samples. A magnetic-HLB (hydrophilic lipophilic balanced) material was synthesized and applied as an adsorbent in magnetic solid-phase extraction (MSPE) for the enrichment of the analytical targets. Furthermore, with the solid-phase isotope labeling, the desalting and removal of labeling residuals could be simplified over conventional in-solution labeling. In addition to overcoming the matrix effect by isotope dansylation, the sensitivity for the analysis of phenols by LC-HRMS was remarkably improved by over 100-fold. The method was systematically verified, and good accuracy (86.5-104.9%) and precision (<8.6% and <11.4% for intra- and inter-day, respectively) were achieved for the tested 15 phenols. The limits of detection (LODs) of this method were estimated to be 0.2-5 ng L^-1 and 5-100 ng kg^-1 in estuary water and sediment samples, respectively. With this method, samples collected from the Daliao River estuary (Panjin, China) were analyzed. It was found that all of the targeted phenols were detected at concentrations ranging from unquantifiable to 485 ng L^-1 (the total concentration of analytes found in each sample were in the range 822-957 ng L^-1) and unquantifiable to 1368 ng kg^-1 (the total concentration of analytes found in each sample were in the range 2251-2992 ng kg^-1) in water and sediment, respectively.

Determination of estrogens by solid-phase quadruplex stable isotope dansylation coupled with liquid chromatography-high resolution mass spectrometry in environmental samples

Estrogens distribute widely in the environment as endocrine-disrupting chemicals (EDCs), which have to be monitored to evaluate their environmental impact. Aim to improve the analytical throughput of liquid chromatography-high resolution mass spectrometry (LC-HRMS), a quadruplex stable isotope dansylation method was developed, with which three real samples could be quantitatively analyzed in one injection. As the estrogens were at trace level in complex matrices, magnetic solid-phase extraction (MSPE) was applied to enrich these analytes and remove the interfaces. By integrating MSPE and quadruplex stable isotope dansylation, a solid-phase quadruplex labeling method was developed for the LC-HRMS analysis of estrogen analogues. For the tested seven estrogens, the developed method showed low detection limits (0.1-0.5 ng/L for pond water and 0.01-0.05 μg/kg for poultry manure), good precision (RSD < 5.5%) and accuracy (96.8-108.3%). The method was applied in the determination of estrogens in environmental samples, and the results revealed that all the tested estrogens were present in the estuary water (unquantifiable to 71.2 ng/L) and chicken manure (undetectable to 25.43 μg/kg).