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• Magnetic boronic acid hypercrosslinked polymer was prepared via one-pot strategy. • The sorbent possessed good extraction capability for OH-PAHs and catecholamines. • Boronate affinity and π-π stacking played important role in the extraction. • The proposed method provides lower LODs and higher precisions. Urinary hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and catecholamines (CAs) are important biomarkers of PAHs exposure. In this study, a novel magnetic boronic acid hypercrosslinked composite (Fe 3 O 4 @HCP-BA) is synthesized using a facile one-pot strategy and applied as a sorbent for the simultaneous extraction of OH-PAHs and CAs in urine samples. The synthesized Fe 3 O 4 @HCP-BA composites are characterized by rich pore structure, highly specific surface area, good magnetic response, and excellent selectivity and adsorption efficiency (range: 65.26–496.71 and 1227.3–1581.8 µmol g−1 for CAs and OH-PAHs, respectively). The mechanisms governing the adsorption of the OH-PAHs and CAs to the Fe 3 O 4 @HCP-BA composites were systematically studied via adsorption kinetics, isotherm models, XPS characterization, and molecular simulation. The resultant Fe 3 O 4 @HCP-BA composite-based MSPE/HPLC-FLD method exhibited good linearity (R2 > 0.9916), low limits of detection (0.2–0.3 pg mL−1 and 0.2–0.3 ng mL−1 for OH-PAHs and CAs, respectively), and good precision (intra-day and inter-day RSDs < 11.1%). The analysis of CAs and OH-PAHs in the urine samples from 14 smokers and 14 non-smokers revealed a positive correlation between the concentrations of CAs and OH-PAHs. Our findings not only establish the proposed method as a green, environmentally friendly, and simple strategy for preparing magnetic adsorbents, but also confirm it as a promising alternative method for accurate determination of OH-PAHs and CAs in biological samples. [ABSTRACT FROM AUTHOR]

Robust, efficient identification and accurate quantification of N -glycans are of great significance in N -glycomics analysis. Here, a simple and rapid derivatization method, based on the combination of microwave-assisted deglycosylation and 6-aminoquinolyl- N -hydroxysuccinimidyl carbamate (AQC) labeling, was developed for the analysis of N -glycan by high performance liquid chromatography with fluorescence detection (HPLC-FLD). After optimizing various parameters affecting deglycosylation and derivatization by RNase B, the time for N -glycan labeling was shortened to 50 min with ∼10-fold enhancement in detection sensitivity comparing to conventional 2-aminobenzoic acid (2-AA) labeling method. Additionally, the method showed good linearity (correlation coefficients > 0.991) and reproducibility (RSD < 8.7%). These advantages of the proposed method were further validated by the analysis of complex samples, including fetuin and human serum. Investigation of serum N -glycome for preliminary diagnosis of human lung cancer was conducted, where significant changes of several N -glycans corresponding to core-fucosylated, mono- and disialylated glycans have been evidenced by a series of statistical analysis. [ABSTRACT FROM AUTHOR]

Legal limits for phenol and bisphenol-A (BPA) in toys are 15 and 0.1 mg L −1 respectively. The latest studies show that in Europe the content of BPA, which reaches our bodies through different contact routes, in no cases exceed legal limits. But it is true that the effects caused by continued intake of this analyte for a long time and other possible processes that could increase their migration, are still under consideration by the health agencies responsible. A multiresponse optimization using a D-optimal design for simultaneously optimising two experimental factors (temperature and flow) at three levels and one (mobile phase composition) at four levels, in the determination by means of HPLC-FLD is proposed in this work. The D-optimal design allows ones to reduce the experimental effort from 36 to 11 experiments guaranteeing the quality of the estimates. The model fitted is validated and, after the responses are estimated in the whole experimental domain, the experimental conditions that maximize peak areas and minimize retention times for both analytes are chosen by means of a Pareto front. In this way, the sensitivity and the time of the analysis have been improved with this optimization. Decision limit and capability of detection at the limits obtained were 33.9 and 66.1 μg L −1 for phenol and 25.6 and 50.0 for BPA μg L −1 respectively when the probabilities of false negative and false positive were fixed at 0.05. The procedure has been successfully applied to determine phenol and BPA in different samples (toys, clinical serum bags and artificial tears). The simulants HCl 0.07 M and water were used for the analysis of toys. The quantity of phenol found in serum bags and in artificial tears ranged from 15 to 600 μg L −1 . No BPA has been found in the objects analysed. In addition, this work incorporates computer programmes which implement the procedure used (COOrdinates parallel plot and Pareto FROnt, COO-FRO) such that it can be used in any other chromatographic optimization. [ABSTRACT FROM AUTHOR]

• The fabricated CPME device can be easily used in bioanalysis. • Sol-gel poly(tetrahydrofuran) was used as sorbent in the microextraction capsule. • Successful application to the extraction of doxorubicin and its metabolites. • The proposed analytical protocol indicated good precision and accuracy. • The method was successfully applied to rat plasma after administration of the drug. In this study, an "all-in-one" microextraction device was designed and fabricated for the extraction of doxorubicin and its two metabolites from rat plasma prior to their determination by high performance liquid chromatography coupled to fluorescence detector. A sol-gel-based sorbent was synthesized in situ and incorporated within two conjoined porous polypropylene tubes together with a cylindrical magnetic bar in order to avoid the need of an external stirring bar. Among other sorbents investigated, the moderately polar sol-gel poly(tetrahydrofuran) was found to be advantageous due to its high affinity toward the target analytes. Systematic investigation of the critical parameters affecting the adsorption and the desorption step was carried out. Due to the "built-in" filtration mechanism of the porous microextraction capsules, the isolation of the analytes was performed directly in the plasma matrix without any previous sample pretreatment (i.e., protein precipitation, centrifugation, etc.). The proposed method was validated in terms of linearity, accuracy, precision, specificity, sensitivity, and stability according to the FDA guidelines. The limits of detection ranged between 1 – 2 ng mL−1 while the lower limits of quantitation of the analytes were calculated as 10 ng mL−1. The accuracy (% relative error) was found within -9.7 – 15.3% under both intra- and inter-day conditions. The precision was better than 13.4% in all cases. ComplexGAPI index was employed to present the green attributes of the developed protocol from the preparation of the microextraction device to the final determination of the analytes. Finally, the applicability of the fabricated stand-alone extraction device was demonstrated in the analysis of the target analytes in rat plasma after intravenous administration of doxorubicin in order to assess its pharmacokinetic profile. [ABSTRACT FROM AUTHOR]

This paper describes a highly sensitive analytical method using high-performance liquid chromatography and fluorescence detection (HPLC–FLD) capable of quantifying trace amounts of synthetic pyrethroid insecticide etofenprox residue in six vegetable samples: bell pepper, cucumber, eggplant, Japanese mustard spinach, spinach, and tomato. After extraction with acetonitrile, the crude sample extract was cleaned up with a solid-phase extraction cartridge. The matrix interference derived from the tested vegetable samples was evaluated. Quantification was conducted using external calibrators prepared in pure acetonitrile. The limits of quantification for etofenprox in each sample were 1.87–3.87 ng/g. Recoveries obtained by application of the proposed analytical method of vegetable samples spiked at the considerably low levels (5–100 ng/g) were 85–111% with relative standard deviations of less than 12%. The proposed method using the HPLC–FLD was applied for trace analysis of the insecticide residue in vegetable samples. [ABSTRACT FROM AUTHOR]

Autoinducer-2 (AI-2), as a small-molecular-weight organic molecule secreted and perceived by various bacteria, enables intra- and inter-species communications. Quantitative determination of AI-2 is essential for exploring the bacterial AI-2-related physiological and biochemical processes. However, current strategies for sensitive detection of AI-2 require sophisticated instruments and complicated procedures. In this work, on the basis of the derivatization of AI-2 with 2,3-diaminonaphthalene, a simple, sensitive and cost-effective high-performance liquid chromatography with fluorescence detector (HPLC–FLD) method is developed for the quantitative detection of AI-2. Under the optimized conditions, this method had a broad linear range of 10–14,000 ng/ml ( R 2 = 0.9999), and a low detection limit of 1.0 ng/ml. Furthermore, the effectiveness of this approach was further validated through measuring the AI-2 concentrations in the cell-free culture supernatants of both Escherichia coli and Vibrio harveyi . [ABSTRACT FROM AUTHOR]

Highlights: [•] A novel fluorescent derivatizing agent 2-hydroxy-1-naphthaldehyde (HN) is developed. [•] A new HPLC–FLD method for the determination of the derivatized metabolites of NF in shrimp is developed. [•] Sample cleanup is achieved using LLE without the adjustment of the pH and further SPE. [•] Separation is achieved on a YMC-Pack Polymer C18 column under alkaline conditions. [ABSTRACT FROM AUTHOR]

Abstract: The application of dispersive liquid–liquid microextraction (DLLME) technique for the rapid analysis of aflatoxins B1, B2, G1 and G2 in maize, rice and wheat products has been evaluated. After extraction of aflatoxins from cereal matrices with a mixture of methanol/water 8:2 (v/v), the analytes were rapidly transferred from the extract to another small volume of organic solvent, chloroform, by DLLME. Aflatoxins were determined using high performance liquid chromatography with florescence detection and photochemical post-column derivatization. Parameters affecting both extraction and DLLME procedures, such as extraction solvent, type and volume of DLLME extractant, volume of water and salt effect, were systematically investigated and optimized to achieve the best extraction efficiency. Under the optimal experimental conditions, the whole analytical method provides enrichment factors around 2.5 times and detection limits (0.01–0.17μgkg−1) below the maximum levels imposed by current regulation for aflatoxins in cereals and cereal products intended for direct human consumption. Recoveries (67–92%) and repeatability (RSD<10, n =3), tested in three different cereal matrices, meet the performance criteria required by EC Regulation No. 401/2006 for the determination of the levels of mycotoxins in foodstuffs. The proposed method was successfully applied to the analysis of retail cereal products with quantitative results comparable to the immunoaffinity chromatography (IAC). The main advantages of developed method are the simplicity of operation, the rapidity to achieve a very high sample throughput and low cost. [Copyright &y& Elsevier]

Abstract: A novel, cost-efficient method for the analytical extraction of the Fusarium mycotoxin zearalenone (ZON) from edible oils by dynamic covalent hydrazine chemistry (DCHC) was developed and validated for its application with high performance liquid chromatography-fluorescence detection (HPLC-FLD). ZON is extracted from the edible oil by hydrazone formation on a polymer resin functionalised with hydrazine groups and subsequently released by hydrolysis. Specifity and precision of this approach are superior to liquid partitioning or gel permeation chromatography (GPC). DCHC also extracts zearalanone (ZAN) but not α-/β-zearalenol or -zearalanol. The hydrodynamic properties of ZON, which were estimated using molecular simulation data, indicate that the compound is unaffected by nanofiltration through the resin pores and thus selectively extracted. The method''s levels of detection and quantification are 10 and 30μg/kg, using 0.2g of sample. Linearity is given in the range of 10–20,000μg/kg, the average recovery being 89%. Bias and relative standard deviations do not exceed 7%. In a sample survey of 44 commercial edible oils based on various agricultural commodities (maize, olives, nuts, seeds, etc.) ZON was detected in four maize oil samples, the average content in the positive samples being 99μg/kg. The HPLC-FLD results were confirmed by HPLC–tandem mass spectrometry and compared to those obtained by a liquid partitioning based sample preparation procedure. [Copyright &y& Elsevier]

• Robustness space for the chromatographic analysis of polycyclic aromatic hydrocarbons. • Method operable design region obtained with a partial least squares model inversion • Handling experimental conditions in HPLC-FLD to fulfil critical quality attributes. • A computational algorithm to invert a latent variables regression model • Analytical quality by design, a useful tool to maintain the quality of a chromatogram. A chromatographic method with the Analytical Quality by Design (AQbD) methodology is developed for the simultaneous determination by HPLC-FLD of ten PAHs (naphthalene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo[a]anthracene, perylene, benzo[b]fluoranthene, and benzo[a]pyrene), widely spread in the environment. The construction of the Method Operable Design Region (MODR) is conducted, for the first time, via the inversion of a multiresponse Partial Least Squares (PLS2) model, which is needed to maintain the correlations among the Critical Method Parameters (CMP), among the Critical Quality Attributes (CQA), and the covariance between one another. The five CMP considered were the composition of the mobile phase (water, methanol, acetonitrile), flow rate, and column temperature. The eight CQA were linked to resolution between peaks recorded in the same emission wavelength (greater than 1.4) and the total time (less than 15 minutes). By systematic use of experimental design and parallel coordinates plots to explore the Pareto optimal front obtained with the PLS2 model inversion, the computed MODR is formed by convex combinations of eight specific settings of Critical Method Parameters that have a mobile phase with percentages of water between 37 and 38 %, of methanol from 13 and 22 %, and of acetonitrile between 41 and 49 %, together with a flow rate between 1.47 and 1.50 mL min−1, and column temperature between 41.9 and 44.0 °C in their adequate combinations. All the chromatographic peaks are well resolved, with total time varying between 12.96 and 15.66 min inside the estimated MODR and the analytical method is accurate with CCβ between 0.9 and 7.0 µg L−1 with probability of both false positive and false negative equal to 0.05. [ABSTRACT FROM AUTHOR]

Abstract: An improved sensitive method was developed and validated for the determination of histamine in food samples by using automated on-line pre-column derivatization coupled with high performance liquid chromatography and fluorescence detection (HPLC–FLD). o-Phthaldialdehyde (OPA) was adopted as derivatization reagent, and a “sandwich” (OPA+histamine+OPA) aspiration mode for the automated on-line pre-column derivatization was found to efficiently enhance the method sensitivity and precision. Histamine in food samples was efficiently extracted with a methanol–phosphate buffer solution (50:50, v/v) at 60°C for 30min, and purified with Waters Oasis MCX solid-phase extraction (SPE) cartridge. The limit of quantification for this method is 0.2mg/kg, which is very sensitive for histamine determination. With the “sandwich” injection program, 3.7% of relative standard deviation (RSD) was achieved by five replicative determinations of a sample blank spiked with 0.25mg/kg histamine standard. Histamine in food samples such as fumitory skipjack and mackerel was analyzed with relative recoveries over 95% at spiking level of 150mg/kg, as well as canned tuna fish and cheese with relative recoveries up to 98% at spiking levels of 0.50 and 5.0mg/kg, respectively. The proposed method was validated with a sample from the Food Analysis Performance Assessment Scheme (FAPAS) as a standard certified material; and the results (140±6mg/kg) agreed well with the assigned value (139mg/kg). [Copyright &y& Elsevier]

Abstract: The presence of paralytic shellfish poisoning (PSP) toxins has not been recorded in the Portuguese coast since 1995. A bloom of Gymnodinium catenatum occurred in the NW coast of Portugal in the autumn of 2005, and PSP profiles were determined in several inshore and offshore shellfish species by HPLC after pre-column oxidation. Most of the species studied contained a complex toxin profile, typically representative of contamination by G. catenatum. However, clams such as Spisula solida contained mainly decarbamoyl toxins, while less extensive transformation was found in Scrobicularia plana. In vitro incubation of S. solida digestive glands with PSP standards revealed a rapid transformation of carbamate and N-sulfocarbamoyl toxins into their corresponding decarbamate analogues. After 24h, less than 5% of the carbamate or N-sulfocarbamoyl toxins tested remained. After a 24h in vitro incubation of S. plana digestive glands, no decarbamate analogues were detected. Artificial toxification of S. plana with cultures of G. catenatum revealed the conversion into decarbamoyl analogues progressed slowly: initially dcGTX2+3 and dcSTX accounted only for 5% of total non N-1 hydroxilated toxins, after 6 days these toxins accounted for 41% of the toxin composition. In vitro incubations of digestive glands from other commercial bivalves did not reveal production of decarbamoyl analogues over a 24h period. [Copyright &y& Elsevier]

Abstract: A new method for the simultaneous determination of three fluoroquinolones (FQs) enrofloxacin (ENRO) ciprofloxacin (CIPRO) and sarafloxacin (SARA) in table eggs has been developed, applying pressurized liquid extraction (PLE) and liquid chromatography (LC) with fluorescence detection (LC-FLD). The influence of several extraction parameters (e.g. solvent mixture, temperature and extraction time) on FQs extraction efficiency and coextracted matrix interferents was evaluated using fortified control eggs and matrix matched standard curves. The results showed that FQs extraction efficiency depends mainly on solvent composition and the optimum extraction mixture was found to be phosphate 50mM, pH 3.0/acetonitrile (50:50, v/v). The optimized procedure employed 50% flush volume, 5min of static time and three extraction cycles at 70°C and 1500psi. Method validation was performed according to the guidelines of the Directive 96/23/EC, using control egg samples, fortified with the target FQs in the range 50–1000ngg−1 and applying the optimized extraction conditions on three different days, providing recoveries between 67–90% with RSDs lower than 11% in all cases. The decision limit (CCα) and detection capability (CCβ) of the analytical method were found to be within the range 17–24ngg−1 and 30–41ngg−1, respectively. The method was successfully applied to the determination of ENRO and its metabolite CIPRO in incurred egg samples from ENRO-treated hens and LC–MS has been used and for confirmatory purposes. [Copyright &y& Elsevier]

• A non-target analysis by P&T GC-MS was performed to investigate can coatings. • ATR-FTIR was used to characterize the type of coating. • A multi-method for bisphenol compounds was validated by using HPLC. • Human exposure to bisphenol compounds was assessed. • The presence of bisphenol compounds in beverage samples was investigated. Major type of internal can coating used for food and beverages is made from epoxy resins, which contain among their components bisphenol A (BPA) or bisphenol A diglycidyl ether (BADGE). These components can be released and contaminate the food or beverage. There is no specific European legislation for coatings, but there is legislation on specific substances setting migration limits. Many investigations have paid attention to BPA due to its classification as endocrine disruptor, however, few studies are available concerning to other bisphenol analogues that have been used in the manufacture of these resins. To evaluate the presence of this family of compounds, ten cans of beverages were taken as study samples. Firstly, the type of coating was verified using an attenuated total reflectance-FTIR spectrometer to check the type of coating presents in most of the samples examined. A screening method was also performed to investigate potential volatiles from polymeric can coatings of beverages using Purge and Trap (P&T) technique coupled to gas chromatography with mass spectrometry detection (GC-MS). Moreover, a selective analytical method based on high performance liquid chromatography with fluorescence detection (HPLC-FLD) for the simultaneous identification and quantification of thirteen compounds including bisphenol analogues (BPA, BPB, BPC, BPE, BPF, BPG) and BADGEs (BADGE, BADGE.H 2 O, BADGE.2H 2 O, BADGE.HCl, BADGE.2HCl, BADGE.H2O.HCl, cyclo-di-BADGE) in the polymeric can coatings and in the beverage samples was applied. In addition, a liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method was optimized for confirmation purposes. The method showed an adequate linearity (R 2 >0.9994) and low detection levels down to 5 µg/L. Cyclo-di-BADGE was detected in all extracts of polymeric coatings. The concentrations ranged from 0.004 to 0.60 mg/dm2. No detectable amounts of bisphenol related compounds were found in any of the beverage samples at levels that may pose a risk to human health, suggesting a low intake of bisphenols from beverages. [ABSTRACT FROM AUTHOR]