The present paper discusses the use of a high-concentration-capacity tool, HiSorb, to investigate the impact of capsule material on the aroma profile of espresso-brewed coffee. The specific high-concentration-capacity probe used is characterized by a sorbent volume (63 μL) intermediate between the solid-phase microextraction (SPME) fiber (0.6 μL) and the stir-bar sorptive extraction rod (126 μL). The extraction performance of the HiSorb was compared, in terms of both absolute signal and compound coverage, with both an equivalent sorbent (polydimethylsiloxane) and a divinylbenzene/carboxen/polydimethylsiloxane SPME fiber using both targeted and untargeted approaches. The HiSorb showed superior extraction compared with the SPME fibers. The HiSorb was then optimized in terms of extraction time and temperature and used to investigate the volatile profile of 23 espresso-brewed coffees prepared with capsules made of different materials-aluminum, compostable, and aluminum multilayer pack-prepared using a refillable capsule. Comprehensive two-dimensional gas chromatography equipped with a reverse fill/flush flow modulator and coupled to mass spectrometry was used to obtain a chromatographic fingerprint of the volatile profile of the brewed coffee. The data were aligned and compared using a tile-based approach, and the results were obtained by performing raw data mining within the same software platform. The data mining enabled the extraction of informative features responsible for the differentiation between the different capsule materials, showing a significant depletion in aroma intensity in the compostable capsule.

As the global population grows and science and technology development evolve, fulfilling basic human needs has been even more linked to technological solutions. In this review, we present an overview of the biosensor market and discuss the factors that make certain countries more competitive than others in terms of technology and innovation and how this is reflected in the trends in publication and patent filling. Additionally, we expose briefly how the COVID-19 pandemic acts as a catalyst for the integration of research and development, business, and innovation sectors to bring solutions and ideas that have been predicted as tendencies for the future.

This study is one of the first to investigate the recovery rate of high- and low-density microplastic particles (polyvinyl chloride and polypropylene) from wastewater treatment plant effluents or comparable technical facilities under nearly realistic experimental conditions. For this purpose, a method of continuous dosing of microplastic particles into an experimental flume for open-channel flow was developed. Subsequently, 12 samples were taken using volume-reduced sampling and the entire sample purification process including oxidative treatment (with hydrogen peroxide and sodium hypochlorite), density separation (with sodium polytungstate), and subsampling was carried out. Detection was conducted using automatic particle recognition and µ-Ramanspectroscopy. An average recovery rate of 27 ± 10% was determined for polypropylene microplastic particles (d = 53 ± 29 µm), decreasing with the particle size, and 78 ± 14% for polyvinyl chloride microplastic particles (d = 151 ± 37 µm). The results suggest that microplastic emissions from wastewater treatment plants are underestimated, particularly because the recovery rate of small microplastic particles < 50 µm is only 9%.

The goal of the present research was to develop a method based on a miniaturized solvent extraction step (using only 500 μL of acetonitrile, with no further clean-up or concentration processes) prior to cryogenic-modulation comprehensive two-dimensional gas chromatography-tandem mass spectrometry for the determination of seventy pesticides in extra virgin olive oil, exploiting the enhanced specificity and sensitivity of this technique. Limits of quantification were always below European legislation residue limits, intra-day precision was between 0.3 and 4.9% (at the 50 and 100 μg kg-1 concentration levels), inter-day precision was between 1.6 and 6.1% (at the 100 μg kg-1 concentration level), recovery (at the 20, 50, and 100 μg kg-1 concentration levels) was in the 14-120% range, accuracy at the initial stage of the work (within repeatability conditions) was between 79 and 110%, while accuracy after 3 months (within intermediate precision conditions) was between 91 and 121% (at the 50 and 100 μg kg-1 concentration levels). Finally, the matrix effect was always positive, between 16 and 197%. The method was applied to the investigation of twenty samples, and eleven of these were found to be contaminated.

The aim of this study was to track changes in the volatilome of cold-pressed oil and press cakes obtained from roasted seeds and to combine it with the profile of non-volatile metabolites in a single study, in order to understand pathways of volatile organic compound (VOC) formation caused by thermal processing. Comprehensive two-dimensional gas chromatography-time of flight mass spectrometry was used for the analysis of VOCs in cold-pressed oils and corresponding press cakes obtained after roasting of seeds at 140 and 180 °C prior to pressing. Contents of primary metabolites (amino acids, saccharides, fatty acids) as well as selected secondary metabolites (glucosinolates, polyphenols) were determined, as many of them serve as precursors to volatile compounds formed especially in thermal reactions. After roasting, the formation of Maillard reaction products increased, which corresponded to the reduction of free amino acids and monosaccharides. Moreover, levels of the products of thermal oxidation of fatty acids, such as aldehydes and ketones, increased with the increasing temperature of roasting, although no significant changes were noted for fatty acids. Among sulphur-containing compounds, contents of the products and intermediates of methionine Strecker degradation increased significantly with the increasing temperature of roasting. Degradation of glucosinolates to nitriles occurred after thermal treatment. The results of this study confirmed that seed roasting before cold pressing has a significant effect on the volatiles, but also indicated roasting-induced changes in non-volatile metabolites of oil and press cake. Such an approach helps to understand metabolic changes occurring during rapeseed processing in cold-pressed oil production.

A new approach is introduced for rapid and reliable bacteria detection in food. Namely, static headspace-comprehensive two-dimensional gas chromatography (HS-GC × GC) with backflushing. The introduced approach provides fast detection of Escherichia coli (E. coli) in enriched ultra-high-temperature processed (UHT) dairy milk. The presence of E. coli may be indicated by detecting microbial volatile organic compounds emanating from test solutions inoculated with E. coli. In the present investigation, HS-GC × GC analysis is preceded by conventional enrichment in nutrient broth and inoculated samples are clearly discernable from controls following as little as 15 h sample enrichment. Headspace equilibration for 28 min followed by an 8 min GC × GC analysis of enriched test solutions reduces time-to-response by approximately one full day compared to conventional culture-based methods. The presence of ethanol, 1-propanol, and acetaldehyde may be used as a putative marker of E. coli contamination in milk and the introduced approach is able to detect single-cell initial bacterial load. Faster, reliable detection of pathogens and/or spoilage microbes in food products is desirable for the food industry. The described approach has great potential to complement the conventional workflow and be utilised for rapid microbial screening of foodstuff.

In this work, we developed an in-tube solid-phase microextraction (SPME) device consisting of a fused silica capillary modified with a polyvinyl alcohol (PVOH) hydrogel. Methylparaben, ethylparaben, propylparaben, and butylparaben were determined in human milk samples by using the in-tube SPME device coupled with liquid chromatography with spectrophotometric detection in the ultraviolet region (LC-UV). The inner surface of the fused silica capillary was silanized to allow covalent modification with the PVOH-hydrogel, using glutaraldehyde as cross-linking agent. The developed device was used up to 250 times with no reduction in the analytes' peak areas or carryover effect, besides having a low production cost. The human milk samples showed a significant matrix effect for parabens with higher logKo/w. Low limits of quantification (LLOQ) between 10.0 and 15.0 ng mL-1 were obtained with RSD values in the range of 1.18 to 18.3%. For the intra- and inter-day assays, RSD values from 5.6 to 16.5% and accuracy from 74.5 to 128.8% were achieved. The PVOH-based hydrogel sorbent allowed the use of water as desorption solvent, eliminating the use of organic solvents, which follows the principles of green chemistry. The results showed a great application potential of the PVOH-based hydrogel sorbent for the extraction of organic compounds from high-complexity samples.

Comprehensive two-dimensional gas chromatography (GC×GC) is becoming increasingly more common for non-targeted characterization of complex volatile mixtures. The information gained with higher peak capacity and sensitivity provides additional sample composition information when one-dimensional GC is not adequate. GC×GC generates complex multivariate data sets when using non-targeted analysis to discover analytes. Fisher ratio (FR) analysis is applied to discern class markers, limiting complex GC×GC profiles to the most discriminating compounds between classes. While many approaches for feature selection using FR analysis exist, FR can be calculated relatively easily directly on peak areas after any native software has performed peak detection. This study evaluated the success rates of manual FR calculation and comparison to a critical F-value for samples analyzed by GC×GC with defined concentration differences. Long-term storage of samples and other spiked interferences were also investigated to examine their impact on analyzing mixtures using this FR feature selection strategy. Success rates were generally high with mostly 90-100% success rates and some instances of percentages between 80 and 90%. There were rare cases of false positives present and a low occurrence of false negatives. When errors were made in the selection of a compound, it was typically due to chromatographic artifacts present in chromatograms and not from the FR approach itself. This work provides foundational experimental data on the use of manual FR calculations for feature selection from GC×GC data.

Pesticides are traditionally analyzed using conventional gas chromatography. When fast chromatography is associated with comprehensive two-dimensional gas chromatography (GC × GC), the resulting method presents high-resolution separation associated with a higher chromatographic speed. In the present work, a method for pesticide analysis in sediment samples was developed using quick, easy, cheap, effective, rugged, and safe extraction (QuEChERS) and a hyperspeed GC × GC separation. The QuEChERS procedure reported in the literature was extended to incorporate the analytes tetrachloro-m-xylene, decachlorobiphenyl, trans-chlordane, chlordane, endosulfan lactone, and endosulfan ether. To understand the chromatographic method improvement achieved, the recent concept of average theoretical peak time (ATPT) was used. The ATPT improved from that of the traditional GC × GC separation to the proposed method, and the separation speed can be classified as a hyperspeed separation. The limit of detection and quantitation of the compounds in the standard mix ranged from 0.39 to 17.96 µg L-1 and 1.18 to 54.43 µg L-1, respectively. The method showed acceptable RSD% (relative standard deviation) values and little interference of the sediment matrix in the extraction procedure. The developed method was applied to the determination of a mixture of 19 compounds in 16 sediment samples from the Pirapetinga River and Paraíba do Sul River in Brazil.