The separation and determination of the ten water-soluble vitamins by using capillary electrophoresis in the micellar electrokinetic chromatography in a single run are proposed. The method uses low toxicity and cost solvent (ethanol) as modifier of background electrolyte (BGE) attending to the Green Chemistry principles. The electrophoretic method uses 10.0 % (v/v) ethanol, 2.0 % (w/v) SDS, 0.02 mol L⁻¹borate at pH 8.70 as BGE. The standard and real sample solutions were injected in the eletrophoretic system by hydrodynamic injection under pressure of 0.80 psi for 8 s, and the separation was carried out in a fused silica capillary under a potential of 28 kV at 25 °C; the analytical signals were monitored at 214 nm. The analytical method is precise (r.s.d. < 6 %), accurate (better than 9 %), selective, sensitive, robust, simple, and presents high analytical frequency as ten water-soluble vitamins were separated in only 18 min, with migration times of 5.75 ± 0.02, 6.81 ± 0.02, 8.13 ± 0.04, 8.80 ± 0.07, 8.98 ± 0.06, 11.10 ± 0.08, 11.34 ± 0.05, 13.85 ± 0.15, 14.82 ± 0.04, and 17.85 ± 0.30 min. Detection and quantification limits of 0.34, 0.32, 0.27, 0.20, 2.50, 4.98, 4.92, 0.30, 0.86 and 0.28 mg L⁻¹and 1.02, 0.97, 0.83, 0.62, 7.56, 15.09, 14.91, 0.90, 2.59 and 0.83 mg L⁻¹, for vitamins PP (nicotinamide), B₁₂(cyanocobalamin), B₂(riboflavin), B₆(pyridoxine), B₈(biotin), C (ascorbic acid), B₅(pantothenic acid), B₃(nicotinic acid), B₁(thiamine), and B₉(folic acid), respectively. Excellent recoveries (intra and inter-day) were obtained and, when the method was applied to food supplement analyses the results were in agreement with the conventional HPLC methods.

A simple and inexpensive liquid chromatography diode array detector (LC-DAD) procedure has been developed to analyse food dyes in beverages, candies, jams, salted fish, Chinese sausage, and cake. A reverse stationary phase provided sufficient selectivity and chromatographic performance for the separation of 11 water-soluble dyes (tartrazine, amaranth, indigo carmine, ponceau 4R, sunset yellow, allura red, carmoisine, fast green FCF (Food green 3), brilliant blue, quinoline yellow, and indocyanine green). The samples were extracted with 1% ammonium solutions and acetonitrile, purified, and concentrated using a C₁₈ solid-phase extraction (SPE) cartridge for beverages, and weak anion exchange SPE cartridge for solid samples. They were determined using a reverse-phase C₁₈ column with gradient elution of 0.2% ammonium acetate buffer, and acetonitrile as the mobile phase. Multiple-specific wavelengths were used to monitor the dyes in the visible range to provide higher sensitivity and an expanded scope for a large number of analytes. The limit of detection and limit of quantification of the dyes were in the range of 0.2 - 0.5 and 0.5 - 1.0 µg/mL, respectively. The precision of the method ranged from 2.71 to 6.31%, while recovery ranged from 90.8 to 105.6%. The validated method was successfully applied to the quantitative analysis of 11 water-soluble dyes in 36 commercial products obtained from the local supermarket. Application to the analysis of beverages and food samples available to consumers proved that the described methods are suitable for the routine analysis of dyes in food products containing a broad range of dyes.

The valorisation and management of agri‐food waste are currently hot investigation topics which probe the recovery of valuable compounds, such as polyphenols. In this study, high‐pressure/high‐temperature extraction (HPTE) and ultrasound‐assisted extraction (UAE) have been used to study the recovery of phenolic compounds from grape marc and olive pomace in hydroalcoholic solutions. The main phenolic compounds in both extracts were identified by HPLC‐DAD. Besides extraction yield (total polyphenol and flavonoid content) and the antiradical power, polyphenol degradation under HPTE and UAE has also been studied. HPTE with ethanol 75% gave higher phenolic extraction yields: 73.8 ± 1.4 mg of gallic acid equivalents per gram of dried matter and 60.0 mg of caffeic acid equivalents per gram of dried matter for grape marc and olive pomace, respectively. In this study, the efficient combination of ethanol/water mixture with HPTE or UAE has been used to enhance the recovery of phenolic compounds from grape marc and olive pomace. HPLC‐DAD showed that UAE prevents phenolic species degradation damage because of its milder operative conditions.

The present work aimed to determine the bioactive compounds in two rosemary water extracts (RWE1 and RWE2) and to assess their antimicrobial, anti‐adhesive and antibiofilm potentials against the food‐related Bacillus and Pseudomonas species at concentrations; 4, 8, 12, 16 and 20 mg mL⁻¹. Phenolic compounds and isoflavones in the RWEs were determined using HPLC. The concentrations of most bioactive compounds of RWE1 (benzoic, ellagic, gallic and rosmarinic acids, daidzein and genistein) were higher than that of RWE2. The MIC₉₀of RWE1 and RWE2 against all tested bacteria was 12 and 16 mg mL⁻¹, respectively. The anti‐adhesive and antibiofilm doses were higher than MIC₉₀. RWE1 and RWE2 showed potential reduction in the bacterial cell adhesion to HEp‐2 cells – 17.5–64.7 and 12.2–52.9%, respectively. In conclusion, this study emphasises the effective use of RWE as a natural anti‐adhesive and antibiofilm agent against Bacillus and Pseudomonas, without difficult extraction procedure.

Food colorants are an important class of food additives that give the first impression to consumers about the quality of food. Ce(IV)-reducing antioxidant capacity assay originally developed in our laboratories was adapted to the determination of synthetic food colorants for the first time. This method allowing for total antioxidant capacity assay of dietary polyphenols, flavonoids, and ascorbic acid in plant extracts is based on the room temperature oxidation of antioxidant compounds with Ce(IV) sulfate in dilute H2SO4 solution and measurement of the absorbance of unreacted Ce(IV) at 320 nm. The results of the proposed method were correlated with high-performance liquid chromatography (HPLC) findings. Individual standard solutions, synthetic mixtures of synthetic colorants, and colorant extracts were identified and quantified with HPLC on a C18 column equipped with a diode array detector, and slight modifications on the existing HPLC method were made to analyze synthetic colorant mixtures. This work proposes Ce(IV)-oxidative spectrophotometry as a complementary technique to HPLC in the analysis of food colorants.

Greywater is increasingly treated and reused for agricultural irrigation in off-grid communities in the Middle East and other water scarce regions of the world. However, there is a dearth of data regarding levels of antibiotics and herbicides in off-grid greywater treatment systems. To address this knowledge gap, we evaluated levels of these contaminants in two types of greywater treatment systems on four farms in the West Bank, Palestinian Territories. Samples of household greywater (influent, n = 23), treated greywater effluent intended for agricultural irrigation (n = 23) and pumped groundwater held in irrigation water ponds (n = 12) were collected from October 2017 to June 2018. Samples were analyzed using high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) for the following antibiotics and herbicides: alachlor, ampicillin, atrazine, azithromycin, ciprofloxacin, erythromycin, linezolid, oxacillin, oxolinic acid, penicillin G, pipemidic acid, sulfamethoxazole, triclocarban, tetracycline, triflualin, and vancomycin. All tested antibiotics and herbicides were detected in greywater influent samples at concentrations ranging from 1.3 to 1592.9 ng/L and 3.1–22.4 ng/L, respectively. When comparing influent to effluent concentrations, removal was observed for azithromycin, alachlor, linezolid, oxacillin, penicillin G, pipemidic acid, sulfamethoxazole, triclocarban, and vancomycin. Removal was not observed for atrazine, ciprofloxacin, erythromycin, oxolinic acid, tetracycline, and trifluralin. Pond water also contained the majority of tested contaminants, but at generally lower concentrations. To our knowledge, this is the first description of an extensive array of antibiotics and herbicides detected in household greywater from off-grid treatment systems.

In the present work, dispersive micro-solid phase extraction (D-μ-SPE) method using magnetic graphene oxide tert-butylamine (GO/Fe₃O₄/TBA) nanocomposite, as an efficient sorbent, was applied for determining 2,4-dichlorophenoxyacetic acid (2,4-D) in water and food samples. Detection was carried out using high-performance liquid chromatography (HPLC) instrument. Influential parameters of D-μ-SPE such as sorbent and its amount, elution solvent and its volume, adsorption and desorption times and pH of sample solution were investigated and optimized. Under the optimized conditions, limit of detection and quantitation values were 0.007 and 0.02 μg/mL, respectively. Recovery data for several real samples were obtained within the range of 88.0–94.0% with a relative standard deviation (RSD) less than 7.5%. The proposed method was successfully applied to quantitative determination of 2,4-D in several vegetables and water samples.

The degradation of 130 mL of mixtures of food azo dyes E122, E124 and E129 has been studied by electro-Fenton (EF) and UVA photoelectro-Fenton (PEF) using a stirred tank reactor with either a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode. The main oxidant was hydroxyl radical formed at the anode from water oxidation and in the bulk from Fenton's reaction between added Fe2+ and H2O2 generated at the cathode. In sulfate medium, fast decolorization was found for all systems, but the almost total mineralization was more rapidly achieved by PEF with BDD. The performance with a real water matrix was slightly worse, although the removal of total organic load was still as high as 95%. The solar PEF (i.e., SPEF) treatment of dye mixtures using a 2.5 L flow plant with a BDD/air-diffusion cell coupled to a planar solar photoreactor is also reported. Fast decolorization and almost total mineralization was found in the presence of either sulfate, perchlorate, nitrate or a mixture of sulfate + chloride ions. In chloride medium, however, the formation of recalcitrant chloroderivatives decelerated the degradation process. Greater current efficiency and lower specific energy consumption were attained in sulfate medium at lower current density and higher azo dye content. A plausible reaction sequence based on 18 aromatic intermediates identified by GC–MS and 6 short-linear carboxylic acids detected by ion-exclusion HPLC has been proposed. The SPEF process promoted the photodegradation of Fe(III)-oxalate complexes and other undetected products. Sulfate and nitrate ions were always released to the medium.

Fabrication of novel coatings continues to be an area of great interest and significance in the development and application of stir bar sorptive extraction (SBSE). In this work, a carboxyl-enriched microporous organic network (MON-2COOH) coated stir bar was designed and fabricated as a novel adsorbent for efficient extraction of four phenylurea herbicides (PUHs) before their determination by high-performance liquid chromatography coupled with photodiode array detector (HPLC-PDA). The MON-2COOH was represented as an effective adsorbent for PUHs due to its large surface area, rigid porous structure, aromatic pore walls and the desired hydrogen bonding sites of introduced carboxyl groups. Variables affecting the SBSE of target analytes were optimized in detail. Under the optimal extraction conditions, favorable correlation coefficients (R² > 0.996) in the linear range 0.10–250 μg L⁻¹, low limits of detection (LODs, S/N = 3) of 0.025–0.070 μg L⁻¹ and good enrichment factors (46–49) were obtained. Besides, the proposed SBSE-HPLC-PDA method was successfully applied to determine trace PUHs in food and environmental water samples with recoveries in the range of 80.0–104.8% and the precisions (relative standard deviations, RSDs) lower than 9.9% (n = 3). This work revealed the potential of MONs in SBSE of trace contaminants from environmental samples.

A molybdenum disulfide(MoS2)-based core-shell magnetic nanocomposite (Fe₃O₄@MoS₂) was synthesized by the stepwise hydrothermal method. Two-dimension ultrathin MoS₂ sheets with a thickness of approximately 20 nm were grown in situ on the surface of Fe₃O₄ (∼200 nm). They were employed as an adsorbent for the magnetic solid-phase extraction (MSPE) of sulfonamide antibiotics (SAs) from water samples. High-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used for SA quantitation. Extraction parameters, including the pH effect, amount of Fe₃O₄@MoS₂, extraction time, temperature, and desorption conditions, were systematically investigated. The electrostatic interaction between the positively charged SAs and negatively charged MoS₂ nanoparticles in the optimal extraction conditions enhanced the adsorption of SAs on the sorbent surface. Under chosen conditions, the proposed strategy achieved wide linear range of 1.0–1000 ng·L⁻¹ SAs, low limits of detection (LOD, 0.20–1.15 ng·L⁻¹, S/N = 3:1), good trueness (recoveries between 85.50–111.5%), satisfactory repeatability and reproducibility (relative standard deviation, <10%, n = 5), and excellent recoveries between 80.20% and 108.6% for SAs determination in spiked waste water samples. The proposed strategy was validated and successfully applied for the analysis of water, milk, pork meat and fish meat. The nanocomposites, which have the combined advantages of magnetic separation and high adsorption affinity toward SAs, are a promising sorbent for antibiotics extraction from real samples.