A highly-efficient and cost-effective pretreatment method for selective extraction and detection of perchlorate in tea and dairy products.

In view of the high polarity and ubiquitous occurrence of perchlorate, achieving an ultra-trace analysis has become a challenging task. The present study aimed to develop a simple and generic pretreatment protocol based on cold-induced liquid-liquid extraction to efficiently extract perchlorate from tea and dairy products and remarkably decrease potential matrix interferences and laborious cleanup. By optimizing the pretreatment conditions, the enrichment factor of perchlorate increased by 7.79 times under the compromise between the matrix effect and extraction recovery. The validated method presented satisfactory selectivity, linearity, accuracy, precision, and matrix effect, providing recoveries of 78.2%-106.2% with RSDr ranging from 1.2% to 7.9% and RSDR less than 10.7% for tea and dairy products. This pretreatment protocol depended only on shaking, freezing, and centrifugation in one step, without additional equipment or tedious operations, which will be explored to a greater extent in complex biological or food matrices.

Ion mobility spectrometry as a fast screening tool for synthetic cannabinoids to uncover drug trafficking in jail via herbal mixtures, paper, food, and cosmetics.

The greatest challenge for European drug policies is how to effectively respond to the dynamic and constantly changing market for new psychoactive substances (NPS). Even small modifications in the chemical structure of substances often allow circumventing existing laws. Also in prison, the consumption of NPS is rising and there is growing evidence that NPS are responsible for a large share of drug-related problems. Ion mobility spectrometry (IMS) is the technique of choice for trace analysis of illicit drugs or explosives at security points, for example airports. Currently, databases of the reduced mobility (K0 ) values are limited to classical drugs and should be completed with data of emerging NPS. In this article, K0 values, LODs (0.7-3.6 ng) and drift times of 25 synthetic cannabinoids were evaluated. The data were added to existing databases of IMS which were then applied for fast screening in prison. The detection capability of the portable IMS technique was evaluated by the determination of intra-day (0.089%) and inter-day precision (0.004% to 0.14%), systematic error (0.19%), and separation capability for structurally related NPS. The applicability of the methodology was demonstrated by the successful analysis of 12 different pieces of paper impregnated with synthetic cannabinoids, 7 different cosmetics, and 5 food samples (liquids), spiked with a mixture of narcotic drugs and a synthetic cannabinoid. In addition, 14 herbal mixtures and 36 different casework samples from prisons were analyzed provided by the State Office of Criminal Investigation Rhineland-Palatinate (Germany).

A Rapid Method for the Determination of Biotin and Folic Acid in Liquid Milk, Milk Powders, Infant Formula, and Milk-Based Nutritional Products by Liquid Chromatography-Tandem Mass Spectrometry.

BACKGROUND: Biotin and folate are B-group vitamins that play a critical role in numerous metabolic reactions, and they are supplemented to infant and adult nutritional formulas as free biotin and folic acid. OBJECTIVE: We describe a rapid method for the analysis of biotin and folic acid that is applicable to liquid milk, milk powders, infant formula, and milk-based nutritional products. METHODS: Samples are autoclaved, centrifuged, filtered, and analyzed by HPLC-MS/MS, with quantitation accomplished by the internal standard technique. RESULTS: The method was shown to be accurate, with acceptable spike recovery (biotin: 96.5-108.2%; folic acid: 92.6-104.4%), and no bias (α = 0.05) against either a certified reference material (biotin: P = 0.70; folic acid: P = 0.23) or established analytical method (biotin: P = 0.10; folic acid: P = 0.48) was found. Acceptable precision was confirmed with repeatability relative standard deviation (RSDr) and Horwitz ratio (HorRat) values (biotin: RSDr = 0.5-5.6%, HorRatr = 0.1-0.6; folic acid: RSDr = 2.0-3.1%, HorRatr = 0.3-0.5). Method detection limit and ruggedness experiments further demonstrated the suitability of this method for routine compliance testing. CONCLUSIONS: This rapid method is intended for use in high-throughput laboratories as part of the routine product compliance release testing of biotin and folic acid in the manufacturing of infant formulas and adult nutritional products.

Novel fast analytical method for indirect determination of MCPD fatty acid esters in edible oils and fats based on simultaneous extraction and derivatization.

A novel method for indirect determination of MCPD esters levels in lipid samples has been developed. The method is based on combination of extraction and derivatization in the same sample preparation step. It is achieved by the application of diethyl ether as extraction solvent for isolation of analytes released from esterified forms from the water phase and as dilution solvent for solid PBA - the derivatization agent. It is a noteworthy improvement of recommended indirect approaches available in the literature because such steps as sample clean-up, multiple liquid-liquid extractions, and preconcentration are excluded in the proposed solution. In this way, the developed procedure is shortened and simplified. Such an approach also minimizes the utilization of organic solvents; therefore, it is in accordance with the principles of "green analytical chemistry." In spite of the fact that the step of sample clean-up is omitted, no deterioration in GC-MS system performance was observed. Equivalence testing of the developed procedure and AOCS cd 29b-13 official method (SGS) has been conducted. It was concluded that results obtained by both methods do not significantly differ statistically. The procedure has been applied to determination of MCPD esters concentrations in lipid fractions isolated by accelerated solvent extraction technique from such foodstuffs as bakery products, salty deep-fried snacks, and instant products. In all investigated samples, the level of bound MCPD was elevated. Additionally, for both procedures, the environmental impact (with the use of analytical Eco-scale) and uncertainty budget have been assessed and compared.

A colorimetric detection of acrylamide in potato chips based on nucleophile-initiated thiol-ene Michael addition.

Acrylamide (AA), a neurotoxin and a potential carcinogen, has been found in various thermally processed foods such as potato chips, biscuits, and coffee. Simple, cost-effective, and sensitive methods for the rapid detection of AA are needed to ensure food safety. Herein, a novel colorimetric method was proposed for the visual detection of AA based on a nucleophile-initiated thiol-ene Michael addition reaction. Gold nanoparticles (AuNPs) were aggregated by glutathione (GSH) because of a ligand-replacement, accompanied by a color change from red to purple. In the presence of AA, after the thiol-ene Michael addition reaction between GSH and AA with the catalysis of a nucleophile, the sulfhydryl group of GSH was consumed by AA, which hindered the subsequent ligand-replacement and the aggregation of AuNPs. Therefore, the concentration of AA could be determined by the visible color change caused by dispersion/aggregation of AuNPs. This new method showed high sensitivity with a linear range from 0.1 µmol L(-1) to 80 µmol L(-1) and a detection limit of 28.6 nmol L(-1), and especially revealed better selectivity than the fluorescence sensing method reported previously. Moreover, this new method was used to detect AA in potato chips with a satisfactory result in comparison with the standard methods based on chromatography, which indicated that the colorimetric method can be expanded for the rapid detection of AA in thermally processed foods.

Rapid determination of polycyclic aromatic hydrocarbons (PAHs) in tea using two-dimensional gas chromatography coupled with time of flight mass spectrometry.

A simple, fast, and cost effective sample preparation procedure has been developed and validated for the determination of 15+1 European Union Polycyclic Aromatic Hydrocarbons (15+1 EU PAHs) in dried tea leave samples. Based on a critical assessment of several sample extraction/clean-up approaches, the method based on the ethyl acetate extraction followed by the use of PAHs dedicated cartridges with molecularly imprinted polymers (MIPs) has been found as an optimal alternative in terms of time demands and obtained good extract purity. For the final identification/quantification of target PAHs, two dimensional gas chromatography coupled to a time-of-flight mass spectrometry (GC×GC-TOFMS) was used. The performance characteristics of the overall analytical method for individual PAHs determined at three spiking levels (0.5, 2.5 and 5 µg kg(-1)) were in following ranges: limits of quantitation (LOQs) 0.05-0.2 µg kg(-1), repeatabilities 2-9%, and recoveries 73-103%. The recoveries achieved by the newly developed sample preparation procedure when employed for naturally contaminated sample ("incurred" PAHs) were comparable to those obtained by other routinely used approaches employing sonication and/or pressurised liquid extraction for sample analytes isolation. The validated method was subsequently used for the determination of selected genotoxic PAHs in 36 samples of black and green tea obtained from the Czech retail market. The levels of ΣPAH4 (sum of benzo[a]anthracene (BaA), chrysene (CHR), benzo[b]fluoranthene (BbFA) and benzo[a]pyrene (BaP)) in black and green tea leaves ranged from 7.4 to 700 µg kg(-1) and from 4.5 to 102 µg kg(-1), respectively. Contamination of tested tea samples by BaP was in the range of 0.2-152 µg kg(-1).

Determination of calcium, copper, iron, magnesium, manganese, potassium, phosphorus, sodium, and zinc in fortified food products by microwave digestion and inductively coupled plasma-optical emission spectrometry: single-laboratory validation and ring trial.

A single-laboratory validation (SLV) and a ring trial (RT) were undertaken to determine nine nutritional elements in food products by inductively coupled plasma-optical emission spectrometry in order to modernize AOAC Official Method 984.27. The improvements involved extension of the scope to all food matrixes (including infant formula), optimized microwave digestion, selected analytical lines, internal standardization, and ion buffering. Simultaneous determination of nine elements (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc) was made in food products. Sample digestion was performed through wet digestion of food samples by microwave technology with either closed- or open-vessel systems. Validation was performed to characterize the method for selectivity, sensitivity, linearity, accuracy, precision, recovery, ruggedness, and uncertainty. The robustness and efficiency of this method was proven through a successful RT using experienced independent food industry laboratories. Performance characteristics are reported for 13 certified and in-house reference materials, populating the AOAC triangle food sectors, which fulfilled AOAC criteria and recommendations for accuracy (trueness, recovery, and z-scores) and precision (repeatability and reproducibility RSD, and HorRat values) regarding SLVs and RTs. This multielemental method is cost-efficient, time-saving, accurate, and fit-for-purpose according to ISO 17025 Norm and AOAC acceptability criteria, and is proposed as an extended updated version of AOAC Official Method 984.27 for fortified food products, including infant formula.

Production and characterization of antibodies against crosslinked gelatin nanoparticles and first steps toward developing an ELISA screening kit.

Nanotechnologies are finding a growing range of applications in the food sector. Nanoparticles are used notably to add vitamins and other nutrients to foods and beverages without affecting taste and color. They are also used to develop new tastes, preserve food texture, control the release of flavors, improve the bioavailability of compounds such as antioxidants and vitamins, and monitor freshness with nanosensors. Crosslinked gelatin nanoparticles are a component of nano-sized carriers for nutrient and supplement delivery in foods and related products. This paper describes the production and characterization of polyclonal antibodies against gelatin nanoparticles. Two immunization schemes were investigated: subcutaneous injection with and without a first intravenous injection. Two enzyme-linked immunosorbent assay formats were used to characterize the antibodies: an inhibition format with an antigen-coated plate for detection of the immune response and a sandwich format for development of the method. The antibodies showed good sensitivity with an IC50 equal to 0.11 ng mL(-1) using indirect ELISA format and a good specificity for the nanomaterials, without significant cross-reactivity against native gelatin. The limit of detection was determined-0.42, 0.27, 0.26, and 0.24 µg mL(-1) for apple, orange juice, milk, and soft drink matrices, respectively. ELISA technology offers rapid, low-cost assays for screening foods, feeds, and beverages. We have studied a prototype ELISA for detection of gelatin-based nanocarrier systems. Fruit juices, milk, and a soft drink were the matrices selected for assay development.

Sulfite determination by a biosensor based on bay leaf tissue homogenate: very simple and economical method.

Of all the food additives for which the FDA has received adverse reaction reports, the ones that most closely resemble true allergens are sulfur-based preservatives. Sulfites are used primarily as antioxidants to prevent or reduce discoloration of light-colored fruits and vegetables, such as dried apples and potatoes, and to inhibit the growth of microorganisms in fermented foods such as wine. This work aims to prepare an electrochemical biosensor based on bay leaf tissue homogenate that contains polyphenol oxidase enzyme abundantly for sulfite detection in foods. The principle of the biosensor is based on the inhibition effect of sulfites on polyphenol oxidase in the bioactive layer. Optimum conditions for the biosensor, such as temperature and pH, were investigated. Some stability parameters of the biosensor were also identified. The biosensor showed a linear calibration graph in the range of 25-100 microM sulfite. The biosensor presents a very simple, economical, reliable, and feasible method for sulfite detection in foods.

Development of techniques for the analysis of isoflavones in soy foods and nutraceuticals.

PURPOSE OF REVIEW: For over 20 years, soy isoflavones have been investigated for their ability to prevent a wide range of cancers and cardiovascular problems, and numerous other disease states. This research is underpinned by the ability of researchers to analyse isoflavones in various forms in a range of raw materials and biological fluids. This review summarizes the techniques recently used in their analysis. RECENT FINDINGS: The speed of high performance liquid chromatography analysis has been improved, allowing analysis of more samples, and increasing the sensitivity of detection techniques allows quantification of isoflavones down to nanomoles per litre levels in biological fluids. The combination of high-performance liquid chromatography with immunoassay has allowed identification and estimation of low-level soy isoflavones. The use of soy isoflavone supplements has shown an increase in their circulating levels in plasma and urine, aiding investigation of their biological effects. The significance of the metabolite equol has spurned research into new areas, and recently the specific enantiomers have been studied. SUMMARY: High-performance liquid chromatography, capillary electrophoresis and gas chromatography are widely used with a range of detection systems. Increasingly, immunoassay is being used because of its high sensitivity and low cost.

Determination of glycyrrhizin in liqueurs by on-line coupled capillary isotachophoresis with capillary zone electrophoresis.

An on-line coupled capillary isotachophoresis-capillary zone electrophoresis method for the determination of glycyrrhizin in liqueurs is described. The optimised electrolyte system was 5 mM HCl+11 mM epsilon-aminocaproic acid+0.05% hydroxyethylcellulose+30% methanol (leading electrolyte), 5 mM caproic acid+30% methanol (terminating electrolyte) and 20 mM caproic acid+10 mM histidine+0.1% hydroxyethylcellulose+30% methanol (background electrolyte). Method characteristics, i.e., linearity (20-500 ng/ml), accuracy (recovery 99+/-4%), intra-assay repeatability (2%), intermediate repeatability (3.8%) and detection limit (8 ng/ml) were determined. Speed of analysis, low laboriousness, high sensitivity and low-running cost are the typical attributes of the capillary isotachophoresis-capillary zone electrophoresis method. Developed method was successfully applied to analysis of liqueurs with liquorice extract and some foods (sweets and food supplements) containing liquorice. Found levels of glycyrrhizin in liqueurs, sweets and food supplements varied between 1-16 mg/l, 850-1050 mg/kg and 1.6-1.8 g/kg, respectively.