Metals in alcoholic beverages: A review of sources, effects, concentrations, removal, speciation, and analysis

Heavy metals in unrecorded Albanian rakia: A pilot study on a potential public health risk

Unrecorded alcohol has been linked to illness above and beyond that caused by ethanol alone because of the presence of toxic contaminants. While it can be found in all countries, consumption is high in Albania, where it is frequently consumed as a fruit brandy known as rakia. Among the contaminants identified previously in such products, metals including lead have been detected at levels posing a risk to health but there is little information on their presence in rakia. To fill this gap, we measured the level of ethanol and 24 elements among them toxic metals in 30 Albanian rakia samples. We found that 63.3% of rakia samples had ethanol concentration above 40% v/v. We also showed that there was a significant difference between the measured [mean: 46.7% v/v, interquartile range (IQR): 43.4-52.1% v/v] and reported (mean: 18.9% v/v, IQR: 17.0-20.0% v/v) concentrations of ethanol in rakia. Among the metals detected, aluminium, copper, iron, manganese, lead, and zinc were present in rakia samples at concentrations ranging between 0.013 and 0.866 mg/l of pure alcohol (pa), 0.025-31.629 mg/l of pa, 0.004-1.173 mg/l of pa, 0.185-45.244 mg/l of pa, 0.044-1.337 mg/l of pa, and 0.004-10.156 mg/l of pa, respectively. Copper and lead were found to be the greatest concern posing a potential public health risk. Although the estimated daily intake of these heavy metals from unrecorded rakia was below their toxicological threshold, the concentrations of lead and copper exceeded their limit value of 0.2 and 2.0 mg/l of pa specified for spirits in 33% and 90% of samples, respectively. Therefore, the possibility of adverse health effects cannot be excluded completely. Our findings highlight the need for action by policymakers against the risks posed by these products in Albania.

Sol-Gel Graphene Oxide-Coated Fabric Disks as Sorbents for the Automatic Sequential-Injection Column Preconcentration for Toxic Metal Determination in Distilled Spirit Drinks

Sol-gel graphene oxide-coated polyester fabric platforms were synthesized and used for the on-line sequential injection fabric disk sorptive extraction (SI-FDSE) of toxic (i.e., Cd(II), Cu(II) and Pb(II)) metals in different distilled spirit drinks prior to their determination by electrothermal atomic absorption spectrometry (ETAAS). The main parameters that could potentially influence the extraction efficiency of the automatic on-line column preconcentration system were optimized and the SI-FDSE-ETAAS method was validated. Under optimum conditions, enhancement factors of 38, 120 and 85 were achieved for Cd(II), Cu(II) and Pb(II), respectively. Method precision (in terms of relative standard deviation) was lower than 2.9% for all analytes. The limits of detection for Cd(II), Cu(II) and Pb(II) were 1.9, 7.1 and 17.3 ng L^-1, respectively. As a proof of concept, the proposed protocol was employed for the monitoring of Cd(II), Cu(II), and Pb(II) in distilled spirit drinks of different types.

Distilled beverage aging: A review on aroma characteristics, maturation mechanisms, and artificial aging techniques

The market value of distilled beverage relies on its quality with a major contribution of distinctive and fascinating aromas. The aroma of distilled beverage is built on the basis of chemical components and can be modified through a series of physical and chemical processes such as aging. Revealing the hidden knowledge behind the evolution of numerous chemical components during these physicochemical processes in distilled beverages is not only significant but also challenging due to its complex system. In this review, the trends in the changes of associated aroma compounds over aging are proposed on the basis of understanding the relationship between chemical components and aroma profiles of numerous typical distilled beverages. The different aging systems, both classical platforms from Eastern countries (pottery jars) to Western countries (wood barrels), and modern platforms such as artificial aging technologies are outlined and compared with their respective applications. Optimizing aging processes is a challenging but imperative step, which warrants further fundamental knowledge from targeting aging-related molecules to the exploration of multitude physicochemical reaction mechanisms that occur during this process, such as the formation of potent odorant compounds in specific containers and environments, as well as mass transfer processes between solid and liquid interfaces. Understanding these maturation mechanisms of distilled beverages expressed by chemosensory signature holds promise for major improvements in future aging technologies that can efficiently yield stable and high-quality products.

Shedding Light on Metals Release from Chestnut Wood to Wine Spirit Using ICP-MS

Possible effects caused by mineral elements during wine spirit ageing are diverse. In this study, the evolution of the mineral composition of wine spirit during ageing with chestnut (Castanea sativa Mill.) wood was investigated. A wine distillate was aged in 250 L wooden barrels (traditional ageing) and in 50 L glass demijohns with wood staves and micro-oxygenation (alternative ageing). Sampling was performed after 21, 60, 180, 270, and 365 days of ageing. The elemental composition of the wine spirits, including alkaline, alkaline earth metals, and heavy metals, was assessed by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS). For most of the elements, no significant differences between wine spirits from distinct ageing modalities were observed. Ageing time had significant effect on most of them, with different trends and distinct magnitude of changes, depending on each specific element. The concentrations of the mineral elements found in the wine spirits were very low, especially those of heavy metals, which is quite positive in terms of quality and food safety. Novel information on metals released from chestnut wood to wine spirits confirms its appropriateness for ageing this beverage.

An automatic on-line sol-gel pyridylethylthiopropyl functionalized silica-based sorbent extraction system coupled to flame atomic absorption spectrometry for lead and copper determination in beer samples

A novel sol-gel pyridylethylthiopropyl functionalized silica-based sorbent was synthesized and utilized in an on-line column preconcentration system coupled with flame atomic absorption spectrometry for metal determination. The developed platform was used for the determination of Pb(II) and Cu(II) in beer samples, since there are limited automatic methods for routine analysis of alcoholic beverage. For a preconcentration time of 60 s, the calculated enhancement factors were 96 for Cu(II) and 130 for Pb(II). The limits of detection were 0.33 μg L^-1 and 1.98 μg L^-1 for Cu(II) and Pb(II), respectively. Moreover, the RSDs were less than 2.9% indicating good method precision. The method was successfully employed for the analysis of commercially available beers. The Cu(II) content of the samples was 1.6-21.8 μg L^-1 and the Pb(II) content was 7.3-17.6 μg L^-1. The developed manifold exhibited operational simplicity and good performance characteristics, indicating its potential utilization for routine analysis in beer industry.

Elemental composition, rare earths and minority elements in organic and conventional wines from volcanic areas: The Canary Islands (Spain)

The organic wine market is rapidly growing worldwide, both in terms of production and consumption. However, the scientific literature is not conclusive regarding differences in the elemental composition of wines according to their production method, including both major and trace elements. Minerals can be present in wine as a result of both anthropogenic and environmental factors. To date, this has not been evaluated in volcanic contexts, neither has the emergent issue of rare earths and other minority elements as potential sources of food contamination. This study using inductively coupled plasma mass spectrometry (ICP-MS) analyses organic and conventional wines produced in the Canary Islands (Spain), an archipelago of volcanic origin, to compare their content of 49 elements, including rare earths and minority elements. Our results showed that organic wines presented lower potential toxic element content on average than their conventional counterparts, but differences were not significant. Geographical origin of the wine samples (island) was the only significant variable differentiating wine samples by their composition profiles. By comparing our data with the literature, no agreement was found in terms of differences between organic and conventionally-produced wines. This confirms that other factors prevail over elemental composition when considering differences between wine production methods. Regarding the toxicological profile of the wines, five samples (three organic and two conventional) exceeded the maximum limits established by international legislation. This highlights the need for stricter analytical monitoring in the Canary Islands, with a particular focus on Cu and Ni concentration, and potentially in other volcanic areas.

Ethnic food beverages with heavy metal contents: Parameters for associated risk to human health, North-East India

Food beverage consumption is a worldwide age-old practice. It is also a common run-through habit among the tribes of North Eastern parts of India. The food beverage group Jou is a traditionally fermented rice-based beverage by Bodo community of Assam, the largest plain tribe. It is not only consumed by Bodos on regular basis but also widely used in their socio-cultural activities. Joubidwi (JB, fermented product), Joufinai (JF, preserved product) and Jougwran (JG, distilled) are the three varieties of Jou. Herewith, it had been reported; the concentrations of metals such as Cd, Co, Cr, Cu, Fe, K, Mn, Na, Ni, Pb and Zn in the three varieties of Jou to make people aware about the possible health benefits as well as the risks associated with the consumption of Jou. The metal contents were estimated using ICP-OES after digesting the samples with 10:1 mixture of concentrated nitric and concentrated sulfuric acid. The estimated daily intakes (EDI) of metals from consumption of JB, JF and JG were also within the recommended daily allowances (RDA). From the estimated target hazard quotient (THQ) values, it was observed no health risk associated with the consumption of Jou; whereas total target hazard quotient (TTHQ) of Joufinai were associated with more health risks. Metal concentrations of all metals in Bodo beverages was lower in comparison with barely based and wheat based beverages.

A fast, low-cost, sensitive, selective, and non-laborious method based on functionalized magnetic nanoparticles, magnetic solid-phase extraction, and fluorescent carbon dots for the fluorimetric determination of copper in wines without prior sample treatment

A new fluorimetric method for copper(II) determination in wines was developed combining functionalized magnetic nanoparticles (FMNP) and fluorescent carbon dots (FCD). To produce FMNP, Fe₃O₄ was coated with Al₂O₃ forming Fe₃O₄@Al₂O₃ core-shell magnetic nanoparticles and functionalized with PAN and SDS. FCD was synthesized from pineapple juice through hydrothermal carbonization. For copper determination, aliquots of wine, the FMNP dispersion, and Britton-Robinson buffer (pH = 4.0) were mixed under stirring to allow the adsorption of copper by FMNP. Cu-FMNP complex was attracted by a niobium magnet and, after discarding the non-magnetic material, the copper(II) ions were eluted with an FCD dispersion before fluorescence quenching measurements. The proposed method presented a linear range from 0.020 to 0.100 mg L^-1 (r² = 0.9953), RSD (intraday) < 3.0%, and recovery rates from 96 to 105 %. FMNP and FCD properties permitted extraction/preconcentration/determination of copper within 1 min with an enrichment factor of nine and without prior sample treatment.

Reproducibility of elemental profile across two vintages in Pinot noir wines from fourteen different vineyard sites

The reproducibility of elemental profile in wines produced across vintages of 2015 and 2016 has been studied using grapes from a single scion clone of Vitis vinifera L. cv. Pinot noir. Grapevines were grown on fourteen different vineyard sites, from Oregon to southern California in the U.S.A., which span distances from approximately hundreds of meters to 1450 km, while elevations range from near sea level to nearly 500 m. The number of elements quantified in the wines made from the 2016 vintage was thirty, by using inductively coupled plasma mass spectrometry (ICP-MS). These data were compared with the twenty-seven elements quantified and previously reported in wines made from 2015 vintage, including twenty-four elements reported in both vintages. The composition of each element was analyzed by analysis of variance with main effect of vineyard. Wines were classified according to vineyard origin and environmental growing site with a combination of factors correlated with the wine elemental profile. The low variability (< 25%) of certain elements in wines from at least eight sites across both vintages, including Group 1 (Cs, K, Na and Rb), Group 2 (Ba, Ca, Mg and Sr), Group 3B (Eu), Group 13 (Al, B and Ga), Group 15 (As and P) and Co, Fe, Mn, Ni and V, demonstrated the reproducibility over the seasons analyzed (2015 and 2016). The comparison of elemental profile of wines across growing seasons demonstrates the opportunity to reproduce one key aspect of wine chemistry across vintages.

Heavy metal and essential elements in beers from turkey market: A risk assessment study

In this study, the level of arsenic (As), lead (Pb) and cadmium (Cd) and also essential elements in beer samples consumed in Turkey were investigated using the inductively coupled plasma mass spectrometry (ICP-MS) method. The heavy metal-induced non-carcinogenic and carcinogenic risks were calculated. For essential elements, the calculated estimated daily intake of iron (Fe), copper (Cu), selenium (Se) and cobalt (Co) from beer consumption were compared with their toxicity reference values. Tukey post-hoc test showed that As was found at a significantly higher level when compared to Pb. Also, a significant correlation was found between As level and alcohol by volume percent. All samples had a hazard quotient and hazard index <1, indicating no non-carcinogenic risk from exposure to single or multiple heavy metals. Some samples exceeded the threshold limit of acceptable cancer risk for As in the high beer consumer group. This assessment showed that in addition to health implications based on the alcohol content of beer, there might be a carcinogenic risk associated with the heavy metals content of these beverages.

Application of Raman spectroscopy and Machine Learning algorithms for fruit distillates discrimination

Through this pilot study, the association between Raman spectroscopy and Machine Learning algorithms were used for the first time with the purpose of distillates differentiation with respect to trademark, geographical and botanical origin. Two spectral Raman ranges (region I—200–600 cm⁻¹ and region II—1200–1400 cm⁻¹) appeared to have the higher discrimination potential for the investigated distillates. The proposed approach proved to be a very effective one for trademark fingerprint differentiation, a model accuracy of 95.5% being obtained (only one sample was misclassified). A comparable model accuracy (90.9%) was achieved for the geographical discrimination of the fruit spirits which can be considered as a very good one taking into account that this classification was made inside Transylvania region, among neighbouring areas. Because the trademark fingerprint is the prevailing one, the successfully distillate type differentiation, with respect to the fruit variety, was possible to be made only inside of each producing entity.

Monitoring of total potassium in winemaking processes using a potentiometric analytical microsystem

Innovation in products and processes, traceability, food security and quality control are inherent challenges in agri-food sector. Trends in wine production are focused on obtaining natural wines with less chemical intervention. Following this goal, a low cost miniaturized, easy-to-use and highly automated microanalyzer to monitor total potassium in winemaking processes is presented. The microsystem monolithically integrates microfluidics as well as a potentiometric detection system and does not require any sample pretreatment. The analytical features provided are a linear range from 250 to 4000 mg L^-1 K⁺, covering all the concentrations expected in must and wine samples, a detection limit of 75 ± 12 mg L^-1 K⁺, and an adequate reproducibility and repeatability. Sample throughput is calculated at 20 h^-1 with a waste volume generation lower than 4 mL per analysis. The microsystem lifetime is at least 4 months. Different wine and grape juice samples have been analyzed reaching outstanding results.

Prospect on Rare Earth Elements and Metals Fingerprint for the Geographical Discrimination of Commercial Spanish Wines

This paper presents a novel tool for Spanish commercial wine discrimination according to their designation of origin (PDO). A total of 65 commercial wines from different Spanish designation of origin (Alicante, Bullas, Campo de Borja, Jumilla, Castilla la Mancha, Ribeiro, Ribera de Duero, Rioja, Rueda, Utiel-Requena, Valdepeñas and Valencia) were characterized. The rare earth elements (REEs) content was determined by a high-temperature torch integrated sample introduction system (hTISIS) coupled to inductively coupled plasma mass spectrometry (ICP-MS). The REE content was used to draw characteristic PDOs radar charts. Results indicated that the REEs fingerprint provides a good prospect to discriminate the different Spanish PDOs, except for Alicante, Castilla la Mancha, Jumilla, Utiel-Requena and Valdepeñas. Finally, for those PDOs that were not properly distinguished, a second fingerprint obtained from Ba, Co, Cr, Mn, Ni, Pb and V content was used for discrimination purposes.

Influence of Alcohol Content and Storage Conditions on the Physicochemical Stability of Spirit Drinks

The purpose of this study was to investigate the effects of alcohol by volume (ABV) and storage temperature on changes in the clarity of rye and plum distillates, and their content of volatile compounds. Distillates with initial ABVs of 93.26% v/v (rye distillate) and 82.03% v/v (plum distillate) were diluted with deionized water to 40, 50, and 70% v/v. The samples were stored in darkness at different temperatures (−18 °C, 0 °C, 8 °C, 20 °C) for 8 weeks. The results showed that reducing the alcohol content and storage temperature caused turbidity to increase. The samples prepared from rye distillate were characterized by significantly lower turbidity than those produced from plum distillate. The highest increase in turbidity in comparison to the controls was observed in the samples with 40% v/v alcohol content stored at a temperature of −18 °C. Storage of the rye and plum distillates samples at different temperatures resulted in changes to the concentrations of volatile compounds, i.e., lower levels of acetaldehyde and higher alcohols, and increased content of esters. However, the alcohol content and storage temperature had no statistically significant effect on methanol concentration.

Impact of Copper Fungicide Use in Hop Production on the Total Metal Content and Stability of Wort and Dry-Hopped Beer

Transition metals, including copper, iron, and manganese, are known to catalyze the generation of reactive oxygen species (ROS) in beer leading to reduced product stability. Metals in beer are generally derived from raw ingredients. The present study aims to evaluate the impact of brewing and dry-hopping using hops treated with copper-based fungicides (CBFs) on the final transition metal content of model buffer solutions and pilot-scale systems of wort and beer. Copper levels in model wort and beer solutions were elevated (105.6% and 230.4% increase, respectively) when CBF-treated hops were used. In laboratory-prepared wort, elevated copper concentrations were not observed when CBF-treated hops were used for boiling. Dry hopping of beer using CBF-treated hops led to significant increases in total copper content (ca. 75 µg/kg vs. ca. 40–50 µg/kg in the control-hopped beer) when yeast was absent from the treated beer, but not when yeast was present. It was observed that manganese levels were significantly elevated in all hopped beers (ca. 495–550 µg/kg vs. 90–125 µg/kg in the unhopped control), regardless of hop treatment. A hop varietal thiol, 4-Mercapto-4-methylpentan-2-one, was spiked into treated beers, and the rate of oxidative loss was monitored during aging. Rates of thiol loss in treated beer samples did not differ across CBF treatments but were significantly lower in unhopped controls in the absence of yeast (p < 0.0001) and correlated significantly with total manganese content of the beers (R2 = 0.4228, p = 0.0006). The rate of staling in hopped beers as measured by the rate of 1-hydroxyethyl radical generation did not differ among hop treatments, suggesting that excess copper content contributed from the hops does not negatively impact the oxidative stability of the beers. These findings suggest that brewers can use CBF-treated hops without any negative implications for the shelf stability of their beers and do not contraindicate the use of CBF in hops production when necessary.

Heavy metal contamination in recorded and unrecorded spirits. Should we worry?

Heavy metals can be released into all alcoholic beverages during production and storage. However, there is at least a theoretical risk that they could be present in higher, and potentially toxic, concentrations in those produced in the household and small-scale stills common in Central and Eastern Europe, which lack quality control and whose products are unrecorded by authorities. Yet, so far, few studies comparing concentrations of heavy metals in recorded and unrecorded spirits have been published. In this study we ask whether there is any difference between heavy metal concentrations in recorded and unrecorded spirits and, thus, the related health risk. The levels of heavy metals were determined in recorded (n = 97) and unrecorded (n = 100) spirits using inductively coupled plasma optical emission spectrometric analysis and applied to population-based risk assessments, considering average, regular and chronic heavy drinkers. Concentrations of Cu, Zn, and Sn were significantly higher in unrecorded spirits than those in their recorded counterparts and recorded spirits contained significantly higher levels of Fe, Mn, and Ni than unrecorded spirits. Combined exposure to heavy metals posed a potential health risk in chronic heavy drinkers consuming recorded spirits. However, when compared to the health risk arising from drinking large volumes of ethanol, the risk is negligible. Consequently, there are no grounds to worry about the adverse effects of heavy metals from spirits.

Vineyard site impact on the elemental composition of Pinot noir wines

Elemental composition was used to characterize and differentiate 14 wines made from the identical clone of Vitis vinifera cv. Pinot noir (clone 667). The vineyards span distances which range from several hundred meters to 1540 km and their elevations vary from near sea level to nearly 500 m. Twenty-seven elements were observed above the limit of quantitation by using inductively coupled plasma mass spectrometry (ICP-MS) in the wines from at least half of the 14 sites. Concentrations of several elements, including Mo, Er, Na, Li, Cs and Pb, varied by 10-fold across the 14 wines. Multiple factor analysis (MFA) of elemental composition with juice chemistry and site characterization show associations consistent with expectations, such as high Ca with high clay content. These results demonstrate that even when grapevine clone and winemaking protocol are controlled, composition differences in wines produced from sites are mediated by diverse soil and microclimate conditions.

Effects of metals released in strong-flavor baijiu on the evolution of aroma compounds during storage

Storage is essential in improving the quality of strong-flavor baijiu (SFB). Here, we investigated the release behaviors of metals from containers into SFB and their effects on the evolution of aroma compounds during storage. Twenty-six metals were identified in SFB samples. The concentrations of Na, K, Ca, Mg, Al, and Fe obviously increased after storing in pottery jar, whereas those of Fe and Cu greatly increased after storing in stainless-steel vessel. The volatility of most esters, alcohols, ketone, furan, and aldehyde decreased, whereas that of most acids increased after adding the metal ions into fresh SFB. The fluorescence intensity of SFB decreased with increased aging time in pottery jar, whereas the fluorescence intensity of acids was quenched with adding Fe3+ and Cu2+. All these results suggested that some metals released from containers had binding affinities with acids, thereby reducing SFB organoleptic stimulation by forming metal-aroma compound complexes during storage.

Assessment of the Quality of Polluted Areas in Northwest Romania Based on the Content of Elements in Different Organs of Grapevine (Vitis vinifera L.)

The purpose of this study was to evaluate the environmental quality of polluted areas near the Baia Mare Mining and Smelting Complex for future improvements the quality of the environment in polluted areas, such as the city of Baia Mare and its surroundings. Samples of soil and organs of grapevine (Vitis vinifera L.) were collected from Baia Mare, Baia Sprie and surrounding areas (Simleul Silvaniei) and their content of Cu, Zn, Pb, Cd, Ni, Co, As, Cr, Hg were analyzed. Most soil and plant samples showed higher metal concentrations in Baia Mare and Baia Sprie areas compared to Simleul Silvaniei, exceeding the normal values. The results obtained from the translocation factors, mobility ratio, as well as from Pearson correlation study confirmed that very useful information is recorded in plant organs: root, canes, leaves and fruit. Results also indicated that Vitis vinifera L. has some highly effective strategies to tolerate heavy metal-induced stress, may also be useful as a vegetation protection barrier from considerable atmospheric pollution. At the same time, berries are safe for consumption to a large degree, which is a great advantage of this species.

Tramadol, Methadone and Benzodiazepines added to Alcoholic Beverages

AIMS

To search for pharmaceutical additives in illicit alcoholic beverages referred to the laboratory of Legal Medicine Organization in Iran in 2017.

METHODS

Hundred beverages were sampled. Ethanol content was determined by gas chromatography with flame ionization detection (GC-FID) and then a liquid-liquid extraction combined with reversed-phase high performance liquid chromatography equipped with a photodiode array detector (PAD) was employed for the qualitative analysis. The analysis was confirmed using gas chromatography coupled with mass spectroscopy (GC/MS).

RESULTS

In 15% either one or more of the following were detected: tramadol, methadone, diazepam, oxazepam, flurazepam and alprazolam. Tramadol was found with highest frequency.

CONCLUSIONS

The wide availability of addictive pharmaceutical is leading to fortification of alcoholic beverages on some countries. The addition of such depressant additives should be better known because of the potentially fatal consequences of the combination with ethanol, as well as the potential for adverse effects on behavior.

Regeneration of Magnetic Nanoparticles Used in the Removal of Pathogenesis-Related Proteins from White Wines

Protein haze remains a serious problem for the wine industry and requires costly bentonite treatment, leading to significant wine volume loss. Recently developed magnetic separation technology that allows a fast and efficient separation of haze proteins from wine shows promise for the development of an alternative method for white wine fining. The key purpose of this study was to understand the potential of the nanoparticles to be reused in multiple fining and regeneration cycles. Bare and acrylic-acid-based plasma polymer coated magnetic nanoparticles were cleaned with water, 10% SDS/water and acetone/water solution after each adsorption cycle to investigate their restored efficiency in removing pathogenesis-related proteins from three unfined white wines. The concentrations of metals, acids and phenolics were monitored to determine changes in the concentration of these essential wine constituents. The regeneration study verified that the acrylic acid plasma-coated magnetic nanoparticles, which underwent ten successive adsorption-desorption processes, still retained close to the original removal capacity for haze proteins from wines when 10% SDS solution and water were used for surface regeneration. In addition, the concentrations of organic acids and wine phenolic content remained almost unchanged, which are important indicators for the retention of the original wine composition.

A compact time-gated instrument for QDs with low excitation energy and millisecond fluorescence lifetime as signal reporters, and its detection application

Recently, bright quantum dots (QDs) possessing low energy for excitation and long fluorescence lifetime in milliseconds have been reported. These QDs such as Mn doped I(II)-III-VI nanocrystals are promising for highly sensitive time-gated sensing applications with a portable or small benchtop “personal” instrument because their unique optical properties not only ensure a high signal-to-background ratio in time-gated fluorescence-intensity (TGFI) measurement but also significantly simplify the TGFI measurement instrument design criteria. In this work, following up the research progress on these QDs, we developed a compact TGFI measurement instrument with high sensitivity and cost-effectiveness for these QDs (more specifically Mn:AZIS/ZnS QDs) as signal reporters. We applied the instrument for sensitive detection of copper(ii) ions in highly autofluorescent rum (alcoholic beverage) in a fluorescence quenching assay utilizing these QDs for signal transduction. The results from this work suggest that this instrument together with bright QDs with low-energy for excitation and long fluorescence lifetimes should have potential to not only convert many regular (non-time-gated) QD-based fluorescence assays to time-gated assays for higher sensitivities or lower LODs, but also facilitate the development of highly sensitive assays for in-field or point-of-care testing.

Mineral composition of organic and conventional white wines from Italy

Despite of the increased interest of consumers for organic agro-food products and of the growing demand for organic wines, scientific literature reports a limited number of studies aimed to evaluate the chemical composition of organic wine with respect to conventional wine in terms of major and trace metals. In the present study the concentrations of 19 elements (Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) were determined in samples of white wines from Italy, conventionally and organically produced. No significant difference in the mineral composition was found between the two groups, except for Ni, which showed a higher concentration in organic wines. By comparing our data with data from literature it can be pointed out that there is no agreement among the results presented in the different studies referring to comparisons between organically and conventionally produced wines, concluding that the mineral composition of wines depends on factors different from organic/conventional production method.

Antibacterial Activity and Mode of Action of Dihydromyricetin from Ampelopsis grossedentata Leaves against Food-Borne Bacteria

Dihydromyricetin (DMY) has recently attracted increased interest due to its considerable health-promoting activities but there are few reports on its antibacterial activity and mechanism. In this paper, the activity and mechanisms of DMY from Ampelopsis grossedentata leaves against food-borne bacteria are investigated. Moreover, the effects of pH, thermal-processing, and metal ions on the antibacterial activity of DMY are also evaluated. The results show that DMY exhibits ideal antibacterial activity on five types of food-borne bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella paratyphi, and Pseudomonas aeruginosa). The activities of DMY against bacteria are extremely sensitive to pH, thermal-processing, and metal ions. The morphology of the tested bacteria is changed and damaged more seriously with the exposure time of DMY. Furthermore, the results of the oxidative respiratory metabolism assay and the integrity of the cell membrane and wall tests revealed that the death of bacteria caused by DMY might be due to lysis of the cell wall, leakage of intracellular ingredients, and inhibition of the tricarboxylic acid cycle (TCA) pathway.

A review of the analytical methods used for beer ingredient and finished product analysis and quality control

Beer is an incredibly complex beverage containing more than 3000 different compounds, including carbohydrates, proteins, ions, microbes, organic acids, and polyphenols, among others. Beer becomes even more complex during storage, for over time it may undergo chemical changes that negatively affect the flavor, aroma, and appearance. Thus, it can be expected that maintaining the quality of beer throughout its lifetime is a difficult task. Since it is such a popular drink throughout the world, being familiar with proper analytical techniques for beer evaluation is useful for researchers and brewers. These techniques include, but are not limited to, gas chromatography, liquid chromatography, matrix assisted laser desorption/ionization, capillary electrophoresis, mass spectrometry, ultraviolet-visible spectroscopy, and flame ionization detection. This review aims to summarize the various ingredients and components of beer, discuss how they affect the finished product, and present some of the analytical methods used for quality control and understanding the formation of chemicals in beer during the brewing process.

Lead contamination of fruit spirits intended for own consumption as a potential overlooked public health issue? A pilot study

OBJECTIVE

The aim of the study was to analyse the occurrence of lead in selected samples of fruit distilled spirits for own consumptions in terms of possible contribution to the occurrence of alcohol-attributable diseases.

METHODS

In a pilot study, we analysed 18 samples of fruit spirits for own consumption. Most of the samples were distilled in the local growing distilleries in the Žilina Region with exception of 3 samples collected in the Trnava Region (one of them was of Hungarian origin). Sample preparation included previous mineralization with use of microwave decomposition system Multiwave 60 50 Hz. The samples were analysed by atomic absorption spectroscopy with graphic furnace (AAS GBC XplorAA 5000 with GF 5000).

RESULTS

The average ethanol level in our samples was higher in comparison with distributed spirits. We detected lead in all samples. In two of them the concentration was lower than the limit of quantitation (LOQ). The highest lead concentrations were observed in plum spirit from Hungary (581.0 μg/l), and in grape spirit made in the Trnava Region (466.3 μg/l).

CONCLUSIONS

Lead is a widespread contaminant of fruit spirits prepared for own consumption. Taking into consideration its common occurrence and possible multiplicative effect with ethanol, we can assume that lead can contribute to the occurrence of several alcohol-attributable chronic diseases. Due to the insufficient information in this field, our results provide significant insight into the issue and present an important starting point for further research.

Occupational exposure to heavy metals, alcohol intake, and risk of type 2 diabetes and prediabetes among Chinese male workers

OBJECTIVE

Both exposure to heavy metals and alcohol intake have been related to the risk of type 2 diabetes (T2D). In this study, we aimed to assess the potential interactions between metal exposure and alcohol intake on the risk of T2D and prediabetes in a cohort of Chinese male workers.

METHODS

We conducted a cross-sectional analysis of 26,008 Chinese male workers in an occupational cohort study from 2011 to 2013. We assessed metal exposure and alcohol consumption at baseline in these workers who were aged ≥20 years. Based on occupations which were categorized according to measured urine metal levels, multiple logistic regression analyses were used to evaluate the independent and joint effects of metal and alcohol exposure on the risk of T2D and prediabetes.

RESULTS

Risks of T2D (P trend = 0.001) and prediabetes (P trend = 0.001) were significantly elevated with increasing number of standard drinks per week, years of drinking, and lifetime alcohol consumption. An adjusted odds ratio (OR) of 6.1 (95% confidence interval [CI]: 4.8-7.8) was observed for the smelting/refining workers (highest metal exposure levels) who had the highest lifetime alcohol consumption (>873 kg) (P interaction = 0.018), whereas no statistically significant joint effect was found for prediabetes (P interaction = 0.515).

CONCLUSIONS

Both exposures to metal and heavy alcohol intake were associated with the risk of diabetes in this large cohort of male workers. There was a strong interaction between these two exposures in affecting diabetes risk that needs to be confirmed in future studies.

Changes in Metal Ion Concentrations in a Chardonnay Wine Related to Oxygen Exposure during Vinification

The impact of oxygen exposure during winemaking on metal ion concentrations in wine were investigated throughout the winemaking process in a Chardonnay wine. The concentrations of Al, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Sn, and Zn were determined using inductively coupled plasma-mass spectrometry. Oxygen exposure significantly impacted 13 metal ions at different phases of winemaking. However, only the concentrations of Cr, Cu, and Fe were impacted by early oxygen exposure during pressing, with lower Cr and Cu concentrations in wines that were aerobically pressed and lower concentrations of Fe in wines that were inertly pressed. The sequestering of Al, Cu, Ni, and Zn by wine lees was significantly affected by oxygen treatment, with lees collected from wines that were treated oxidatively sequestering significantly greater amounts of Cu and Zn and removing these metals from the wine supernatant. The metal ion that was most affected by oxygen exposure during pressing and handling was Cu, with significantly lower Cu measured in wines that were produced under oxidative conditions. It is known that elevated Cu concentrations have negative implications for wine aroma and flavour. This study demonstrated that oxygen management during winemaking significantly impacts metal ion concentrations in lees and wine, which may decrease the risk of developing taints and faults.

Applying multivariate analysis to characterize waragi spirits from Acoli, Uganda, by their metal contents

Quality control during spirits production and means of authenticating or verifying sources of spirits in the sub-Saharan region of Africa are limited due to lack of resources and the scientific acumen required to develop methodologies for characterizing spirits. However, the increasing needs to protect consumers from negligence, or willful contamination of spirits in this region underscores the urgency with which growth in this area must happen. In this paper, we describe a multivariate statistical framework upon which characterization, identification and authentication of spirits could be developed. The framework exploits the unique chemical fingerprints of spirits with the goal of accomplishing three functions simultaneously: the detection of class differences, the authentication of spirits and the verification of sources. In a test case using the metal contents of 17 Ugandan spirits, this framework shows (i) that a class of unrecorded spirits known locally as Lira-Lira can be singled out from other spirits by their Cu contents, (ii) that localities from where the Lira-Lira spirits were purchased can be resolved to within 8 km by cluster analysis and principal component analysis, (iii) that cluster analysis loadings and scores, placed side-by-side, can pair spirits and their unique discriminating contaminants directly, (iv) that the most important metals for authenticating 13 spirits, source verification and production methods are Al, Sr, Ba, Mn, Zn and Cu (high concentration variability across samples is the qualifying factor), (v) that common sources of contamination can be detected by Pearson correlation analysis (this study finds that Sn/Cd, Pb/Cr, Tl/Cr, Pb/Ni or Cu/Ag as well as the triad Se/As/Ni in the 13 Ugandan spirits are from similar sources), and (vi) that inconsistency in spirits production can be detected with empirical data. Such rudimentary solutions to characterizing spirits have never been offered to the sub-Saharan countries.

Effect of filtration on elimination of turbidity and changes in volatile compounds concentrations in plum distillates

The purpose of this study was to investigate the effect of alcoholic strength by volume (ASV) and storage conditions on turbidity in plum brandies. Different types of filter sheet were also tested for their effects on turbidity, as well as on the chemical composition and organoleptic characteristics of the distillates. The raw materials used were two plum distillates with initial ASVs of 76.77% v/v and 81.92% v/v. The distillates were diluted to alcohol contents of 37.5%, 40% and 50% v/v and stored under various conditions for 64 days. Filtration was performed using two depth filter sheets, with nominal retention rates of 0.40–0.48 μm and 0.80 μm, or with an activated carbon-based filter sheet. The lowest turbidity was observed in samples stored at ambient temperature with an ASV of 50% v/v. Reducing the alcohol content and storage temperature caused turbidity to increase. Samples prepared from distillate with an initial alcohol content of 76.77% v/v were characterized by significantly higher turbidity than those produced from spirit with an initial ASV of 81.92% v/v. Lowering the storage temperature resulted in a larger decrease in the concentration of volatile compounds after filtration. Use of an activated carbon filter sheet caused the greatest decrease in the majority of volatiles. Use of a filter sheet with a nominal retention rate of 0.80 μm led to the greatest improvement in the organoleptics of the tested plum distillates.

Determination of copper and lead in tequila by conventional matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and partial least squares regression

RATIONALE

Quantification of small molecules by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) is challenging yet attractive, due to micro-scale procedural simplicity, high throughput and lack of memory effects. Since these features are important while analyzing trace elements in quality control schemes, MALDI-TOFMS was used for the determination of copper (Cu) and lead (Pb) in tequila with quantification carried out by partial least squares regression (PLS2) and by univariate calibration (UC).

METHODS

In the proposed procedure, Bi(III) was added as internal standard (IS), diethyldithiocarbamate complexes were formed (pH 7.4) and extracted into chloroform; after solvent evaporation and re-constitution in acetonitrile, the sample was co-crystallized with α-cyano-4-hydroxycinnamic acid on a steel target. From the acquired mass spectra, UC was performed using IS-normalized signals of the monoisotopic ions of analytes, and the m/z range 350-513 was used for PLS2. Accuracy was tested by recovery experiments and by inductively coupled plasma (ICP)-MS analysis.

RESULTS

When compared with direct analyte signal measurements, application of IS yielded enhanced analytical performance using either UC or PLS2; the method quantification limits were: 11.1 μg L^-1 , 23.4 μg L^-1 for Cu and 89.8 μg L^-1 , 97.1 μg L^-1 for Pb, respectively. In tequila, MALDI-TOFMS and ICP-MS provided consistent results for Cu (165-2599 μg L^-1 ); Pb was not detected in any sample by MALDI-TOFMS, yet recoveries obtained after standard addition were indicative of acceptable accuracy (400 μg L^-1 Pb added; recoveries: 91.2-108% for UC and 98.8-120% for PLS2).

CONCLUSIONS

New experimental evidence has been provided supporting the inclusion of trace metals quantification within a range of MALDI-TOFMS applications. Slightly better results were obtained for UC as compared with PLS2 yet both methods can be recommended for testing the compliance of Cu and Pb levels with Official Mexican Norm. Of note, while using PLS2, there is no need for signal integration nor for IS normalization.

Highly Ordered Macroporous Poly-3,4- ortho-xylendioxythiophene Electrodes as a Sensitive Analytical Tool for Heavy Metal Quantification

Highly ordered macroporous electrodes of the conducting polymer poly-3,4- ortho-xylendioxythiophene (PXDOT) are presented as a sensitive analytical tool for heavy metal ion quantification due to a controlled gain in electroactive area. They were designed by using colloidal crystal templates. A direct correlation between the final number of porous layers and the deposition charge ( Q_d) employed for electropolymerization is observed. All the electrodes exhibit a surface-templated structure due to an interaction between the radical cation, formed during the electropolymerization, and the surface groups of the silica beads. The voltamperometric response of the macroporous PXDOT electrodes shows a rather fast electron transfer with Δ E_p values between 70 mV and 110 mV. Square wave anodic stripping voltammetric (SWASV) analysis of Cu²⁺ as a representative heavy metal ion shows a linear response in the subppm range. As a model application, the efficient quantification of Cu²⁺ in a commercial mezcal sample is validated by the standard addition method and the results correlate adequately with the values obtained by atomic absorption spectroscopy.

Differences in the levels of pesticides, metals, sulphites and ochratoxin A between organically and conventionally produced wines

Organic products are generally recognized to be healthier and safer than conventional products. However, the actual scientific data regarding the importance of organic production on particular contaminant/additive content of wines is scarce. This study aimed to evaluate contents of pesticides, metals, sulphites and ochratoxin A in organically (org) and conventionally (conv) produced wines from eleven locations in different winegrowing regions of Croatia. All wines contained significantly lower levels of residues as compared to the maximum limits (MLs) with the exception of excessive amounts of Cu and Zn in one sample. Pb and Mg were mainly significantly less represented in org wines. There were no significant differences in the content of sulphite or ochratoxin A between org and conv wines. Significantly lower total pesticide concentrations and average number of pesticides per sample were obtained in org wines. The majority of ochratoxin A positive wines were from conv wine producers.