Food and Beverage Analysis

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.

A group of researchers has studied the migration of monomers and plastic additives from plastic food packaging in microwave heated homemade food and packed liquid food using QuEChERS and gas chromatography coupled to mass spectrometry (GC–MS).

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 us about this research.

Liquid chromatography coupled to tandem mass spectrometry alongside gas chromatography tandem mass spectrometry has been used to analyze 200 pesticides and pesticide metabolites in honeybees.