Food and Beverage Analysis

In this study, general extract screening of food storage materials was done with nontargeted analytical methods to understand what analytes could potentially leach into food or beverages. GC and mass spectral deconvolution effectively separated analytes within the complex mixture and TOF-MS provided full mass range spectral data for identification. This workflow can be used for confident characterization of components present as extractables from food packaging materials.

LCGC spoke to Rudolf Krska from the University of Natural Resources and Life Sciences in Vienna, Austria, about the latest analytical techniques and challenges facing analysts involved in the evolving field of mycotoxin analysis.

Honey is a high-value commodity, whose quality is defined both by its botanical and geographical origin. This generates a strong consumer demand for certain, premium-priced products, which have become the target for adulterations. A useful tool to detect the addition of sugar to honey products is based on the well-documented difference in δ13C values between C3 (natural honey) and C4 (added sugar) plants. Coupling high performance liquid chromatography (HPLC) with isotope ratio mass spectrometry (LC–IRMS) has the unrivaled advantage of the simultaneous determination of δ13C values from glucose, fructose, di-, tri-, and oligo-saccharides, allowing the detection of more sophisticated honey adulteration with a simple user-friendly analytical system.

This study shows that the organic compounds giving rise to the flavour of a variety of beverages can be identified by high-capacity sorptive extraction using PDMS probes, with analysis by thermal desorption–GC–MS.

Traditional extraction methods for food samples, such as liquid-liquid extraction and Soxhlet extraction, are often time-consuming and require large amounts of organic solvents. Therefore, one of the objectives of analytical food safety studies currently has been the development of new extraction techniques that can improve the accuracy and precision of analytical results and simplify the analytical procedure.

Gas chromatography–mass spectrometry (GC–MS) is a widely used technique for food safety and quality assurance applications.

The disposal of food waste can pose serious environmental problems. Food scraps from the kitchen often end up in landfill, where it rots and produces methane, a greenhouse gas.

Non-targeted screening approaches are an essential element of food safety strategies, detecting novel or unexpected food contaminants and adulterants. However, the development and implementation of generalized and non-targeted screening workflows for food matrices is challenging. The inherent sample complexity and diversity as well as large analyte concentration ranges represent significant obstacles.

A brief profile of the Laboratory of Foodomics in Spain, led by Alejandro Cifuentes.

The analysis of hazardous mycotoxins is crucially important in food to ensure the health of humans and animals. Here, a simple and fast analysis including the sample preparation and purification of mycotoxins within food is presented. Ten different mycotoxins were investigated simultaneously in 14 min. The method was applied to the analysis of mycotoxins in apple juice, grape juice, and two different batches of the same branded beer.

The 8th International Symposium on Recent Advances in Food Analysis (RAFA 2017) will take place in Prague, Czech Republic, on 7–10 November 2017.

This article describes a space-saving, quick, and inexpensive sample preparation technique followed by a high performance liquid chromatography (HPLC) method with a 100% water mobile phase and photodiode array (PDA) detection for quantifying acetamiprid and its N-desmethyl metabolite, IM-2-1, in cow’s milk. The analytes were extracted from the sample and deproteinized using a handheld ultrasonic homogenizer with 5% (w/v) trichloroacetic acid solution, purified using a centrifugal monolithic silica spin minicolumn, and quantified within 20 min per sample. The accuracy and precision are well within the international method acceptance criteria.

Using a liquid chromatography–mass spectrometry (LC–MS) method in conjunction with two complementary types of chromatographic retention modes - reversed phase and aqueous normal phase - various compounds present in mesquite flour extracts were identified. Because of the diverse types of chemical constituents found in such natural product extracts, a single chromatographic mode may not be sufficient for a comprehensive characterization. However, the combination of reversed-phase and aqueous normal phase LC can encompass a wide range of analyte polarity. This characterization of the composition of mesquite flour could be used in future studies to elucidate the beneficial health effects of its consumption.

A group of researchers from India have chemically characterized food waste using gas chromatography coupled to mass spectrometry (GC–MS) and GC with flame ionization detection (GC–FID) and identified possible reuse and disposal techniques.

The aroma of a wine is an important part of the wine tasting experience. Angela Lopez-Pinar from the Friedrich-Alexander University Erlangen-Nürnberg in Germany, has been investigating off-odours in wine using gas chromatography–olfactometry (GC–O). She recently spoke to us about this research.

In recent years, Huanglongbing (HLB), or citrus greening disease, has devastated citrus crops throughout the world. Penicillin G has been used to treat HLB infected trees with promising results. However, the metabolites produced from the degradation of penicillin G are known to cause potentially life-threatening allergic reactions; therefore, the concentration and presence of the metabolites must be carefully monitored. We have built and revised an analytical method based on Ultra High Performance Liquid Chromatography in combination with Tandem Mass Spectrometry (UHPLC-MS/MS) in order to identify and quantitate penicillin G and its major metabolites, penillic acid and penilloic acid, in citrus fruit and juice. Here, we discuss the chromatographic conditions and revisions that improved the precision and accuracy of our measurements.

This article describes a workflow for the analysis of phenolic components in wine enabling confident differential analysis using high performance liquid chromatography (HPLC) in combination with low-field drift-tube ion mobility quadrupole time-of-flight mass spectrometry (IMS-QTOF-MS).

Here we propose an exemplary workflow for the analysis of phenolic extracts (i.e. wine) enabling confident differential analysis using high performance liquid chromatography in combination with low-field drift tube ion mobility quadrupole time-of-flight mass spectrometry (HPLC×IMS-QTOFMS). In this workflow, single-field collisional cross section values from low-field drift-tube IMS using nitrogen as drift gas (DTCCSN2) are readily extracted in addition to a retention time and a high resolution mass spectrum for each compound. “Alternating frames” experiments utilizing post-drift tube fragmentation also allow drift time-aligned MS/MS spectra to be obtained. Molecular feature extraction was highly repeatable with average precision values of 0.28% for retention time, 0.18% for drift time, and 1.5 ppm m/z determined for 233 molecular features found in all six technical replicates. The improved selectivity of this strategy increases confidence in intersample molecular feature alignment (i.e. compound identity confirmation), including the resolution of co-eluting isomeric compounds.

A balanced diet is one step closer to a healthy lifestyle. Samantha Duong from the Australian Government’s National Measurement Institute (NMI) has used gas chromatography with flame ionization detection (GC–FID) to measure phytosterols in fortified food. She recently spoke to us about this research.

An automated method for determination of water in liquid sweeteners was developed utilizing headspace gas chromatography (GC) and ionic liquid-based capillary GC columns. This method allowed for the rapid determination of water with minimal sample pretreatment. In addition to providing fast analysis time for the samples, the headspace GC method was found to be accurate and precise for the measurement of water in 16 liquid sweeteners. This method was shown to be widely applicable for sugar and sugarless based sweeteners and likely, more accurate than Karl Fischer titration.

A method based on salting-out assisted liquid-liquid extraction for the analysis of α-dicarbonyls in wines was developed. The sample preparation procedure consists in a single step, involving the simultaneous extraction and derivatization of the analytes using an o-phenylenediamine–acetonitrile solution with NaCl as the salting-out agent. The obtained organic phase is collected and directly analyzed by liquid chromatography with spectrophotometric detection. The studied α-dicarbonyls were determined in eight wines.

Using an LC–MS method in conjunction with two complementary types of chromatographic retention modes-reversed phase and aqueous normal phase-various compounds present in mesquite flour extracts were identified. Because of the diverse types of chemical constituents found in such natural product extracts, a single chromatographic mode may not be sufficient for a comprehensive characterization. However, the combination of reversed phase and aqueous normal phase LC can encompass a wide range of analyte polarity. This characterization of the composition of mesquite flour could be used in future studies elucidating the beneficial health effects of their consumption.

Babies and infants experience rapid growth within a short timeframe and the nutrition that they absorb is therefore of the utmost importance. María Mateos-Vivas from the Department of Analytical Chemistry, Nutrition, and Food Science at the University of Salamanca, Spain, has used hydrophilic interaction liquid chromatography (HILIC) coupled to tandem mass spectrometry (MS/MS) to investigate the role of nucleotides on infant health. She recently spoke to The Column about this research.

Carotenoids are a class of natural pigments, widely distributed in vegetables and fruits. A comprehensive two-dimensional liquid chromatography (LC×LC) method, based on the use of a cyano and an octodecylsilica column, placed in the first and second dimension, respectively, was applied to evaluate carotenoid composition and stability in selected overripe fruits representing the waste generated by a local food market. This research also evaluates if post-climacteric biochemical changes are linked to carotenoid degradation in the investigated fruits. A total of 22 compounds was separated into seven different chemical classes in the two-dimensional space, and identified by photodiode array (PDA) and mass spectrometry (MS) detection. The results prove that the waste generated by the large distribution of food still represent an important source of bioactives that could be used for other purposes.

Monitoring of Glyphosate in crops and water is mandated in many countries. Pickering offers a sensitive and robust HPLC method for analysis of Glyphosate in soy beans, corn and sunflower seeds. This method utilizes a simplified sample preparation procedure that has proven to be effective even for challenging matrices.

Adequate detection of trans-resveratrol in wine is complicated by two factors: relatively low levels and interferences from matrix components. Here, we present two useful approaches to overcoming these issues depending on the instrumentation available. For high performance liquid chromatography (HPLC) analyses with ultraviolet (UV) detection, matrix peaks can be removed by microextraction using a packed sorbent while simultaneously concentrating the trans-resveratrol peak by a factor of two. For liquid chromatography–mass spectrometry (LC–MS), the extracted ion chromatogram for the [M + H]+ analyte ion can be used to obtain specificity without prior extraction procedures.