Fast and simple method of simultaneous preservative determination in different processed foods by QuEChERS and HPLC-UV: Method development, survey and estimate of daily intake.

A fast and simple method, which employs QuEChERS and HPLC-UV, was developed to determine preservatives in processed foods from different classes. The method showed correlation coefficients above 0.99, LOQs between 0.13 and 0.33 mg kg-1 and recoveries between 91 and 107%, with RSD ≤ 5.3%. Levels of preservatives were up to 2040 mg kg-1 for benzoates, up to 3185 mg kg-1 for sorbates and up to 452 mg kg-1 for methylparaben. Only four out of 82 samples under analysis were above the maximum level allowed by the legislation. Additionally, daily intakes of preservatives were estimated. Regarding benzoates, relatively high intakes were estimated (25% of the acceptable daily intake - ADI) in comparison with sorbates (5% of ADI) and parabens (<1% of ADI), when mean consumption is considered. This method is a good alternative to determining preservatives in different food samples.

Development of a LC-MS/MS method for the simultaneous determination of sorbic acid, natamycin and tylosin in Dulce de leche.

A simple extraction, rapid routine method for the simultaneous determination of sorbic acid, natamycin and tylosin in Dulce de leche, a traditional South American product, by liquid chromatography-tandem mass spectrometry has been developed and fully validated. The limits of detection were set to 24.41mgkg(-1) (sorbic acid), 0.10mgkg(-1) (natamycin) and 2µgkg(-1) (tylosin). Recoveries ranged from 95% to 110%. Proportionally, internal standardization was more efficient than external standard, resulting in a smaller measurement of uncertainty. In total, 35 commercial samples from Brazil, Argentina and Uruguay have been assessed. The proposed method was tested on other dairy desserts, demonstrating to be versatile. Although tylosin was not detected in any sample, a high rate of non-compliance was found, with 67.39% of samples above the maximum allowed for sorbic acid and a maximum concentration of 2105.36±178.60mgkg(-1). In two samples, natamycin was irregularly found.

Molecularly imprinted solid-phase extraction and high-performance liquid chromatography with ultraviolet detection for the determination of urinary trans,trans-muconic acid: a comparison with ionic exchange extraction.

A new molecularly imprinted polymer (MIP) has been synthesized for the selective extraction of trans,trans-muconic acid (ttMA) from urine samples, followed by high-performance liquid chromatography analysis with ultraviolet detection. The synthesis was based on non-covalent interactions, and 4-vinylpyridine was used as a functional monomer. The analytical calibration curve was prepared using a pool of five urine samples of non-smokers spiked with ttMA standards with concentrations that ranged from 0.3 to 10 mg L(-1) (r(2) = 0.999). The limit of quantification was 0.3 mg L(-1) (lower than the biological exposure limits suggested by the ACGIH). The within-day and between-day precision and accuracy presented relative standard deviations and relative errors of less than 15%. The analytical frequency was 4 h(-1) (considering extraction and separation/quantification steps), and the same MIP cartridge was efficiently used for approximately 100 cycles. All figures of merit were similar or better than those obtained by the procedure based on ionic exchange extraction. The proposed method could be an interesting alternative for the routine analysis of ttMA in urine for biological monitoring procedures of human exposure to benzene.

Exposure to indoor air pollutants (polycyclic aromatic hydrocarbons, toluene, benzene) in Mexican indigenous women.

UNLABELLED: Indoor air pollution is considered to be a serious public health issue in Mexico; therefore, more studies regarding this topic are necessary. In this context, we assessed exposure to polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds in: (i) women who use firewood combustion (indoor) for cooking and heating using traditional open fire; (ii) women who use firewood combustion (outdoor) for cooking and heating using traditional open fire; and (iii) women who use LP gas as the principal energy source. We studied 96 healthy women in San Luis Potosi, México. Urine samples were collected, and analyses of the following urinary exposure biomarkers were performed by high-performance liquid chromatography: 1-hydroxypyrene (1-OHP), trans, trans-muconic acid, and hippuric acid (HA). The highest levels of 1-OHP, trans, trans-muconic acid, and HA were found in communities where women were exposed to indoor biomass combustion smoke (or products; geometric mean ± s.d., 3.98 ± 5.10 µmol/mol creatinine; 4.81 ± 9.60 µg/l 1-OHP; 0.87 ± 1.78 mg/g creatinine for trans, trans-muconic acid; and 1.14 ± 0.91 g/g creatinine for HA). Our findings indicate higher exposure levels to all urinary exposure biomarkers studied in women who use indoor firewood combustion for cooking and heating (using traditional open fire). PRACTICAL IMPLICATIONS: High mean levels of 1-hydroxypyrene, t,t-muconic acid, and hippuric acid were found in women who use firewood combustion (indoor) for cooking and heating using traditional open fire and taking into account that millions of women and children in Mexico are living in scenarios similar to those studied in this report, the assessment of health effects in women and children exposed to polycyclic aromatic hydrocarbons and volatile organic compounds is urgently needed. Moreover, it is immediately necessary an intervention program to reduce exposure.

Determination of sorbate and benzoate in beverage samples by capillary electrophoresis-Optimization of the method with inspection of ionic mobilities.

The aim of this study was to develop a fast capillary electrophoresis method for the determination of benzoate and sorbate ions in commercial beverages. In the method development the pH and constituents of the background electrolyte were selected using the effective mobility versus pH curves. As the high resolution obtained experimentally for sorbate and benzoate in the studies presented in the literature is not in agreement with that expected from the ionic mobility values published, a procedure to determine these values was carried out. The salicylate ion was used as the internal standard. The background electrolyte was composed of 25 mmol L(-1) tris(hydroxymethyl)aminomethane and 12.5 mmol L(-1) 2-hydroxyisobutyric acid, at pH 8.1. Separation was conducted in a fused-silica capillary (32 cm total length and 8.5 cm effective length, 50 microm I.D.), with short-end injection configuration and direct UV detection at 200 nm for benzoate and salicylate and 254 nm for sorbate ions. The run time was only 28s. A few figures of merit of the proposed method include: good linearity (R(2)>0.999), limit of detection of 0.9 and 0.3 mg L(-1) for benzoate and sorbate, respectively, inter-day precision better than 2.7% (n=9) and recovery in the range 97.9-105%. Beverage samples were prepared by simple dilution with deionized water (1:11, v/v). Concentrations in the range of 197-401 mg L(-1) for benzoate and 28-144 mg L(-1) for sorbate were found in soft drinks and tea.

High-performance liquid chromatography method for urinary trans,trans-muconic acid. Application to environmental exposure to benzene.

This report describes a specific and precise high-performance liquid chromatography (HPLC) method for the quantification of trans,trans-muconic acid in human urine. The procedure involved a highly efficient Bond-Elut SAX extraction with 20% acetic acid elution. The HPLC analysis used a sodium acetate/methanol mobile phase with a C18 reverse phase column and UV detection at 265 nm. The recovery, precision, linearity, and limits of detection and quantification of the method were determined. Mean absolute recoveries were between 97% and 115%. The calibration curve showed a correlation coefficient of 0.9955 and the limit of detection was determined to be 10.8 microg/L. The method is suitable for evaluation of occupational and environmental benzene exposure in humans. The study of urinary trans,trans-muconic acid of two populations of children to evaluate environmental benzene exposure is presented.

New method for the determination of benzoic and sorbic acids in commercial orange juices based on second-order spectrophotometric data generated by a pH gradient flow injection technique.

Two widely employed antimicrobials, benzoic and sorbic acids, were simultaneously determined in commercial orange juices employing a combination of a flow injection system with pH gradient generation, diode array spectrophotometric detection, and chemometric processing of the recorded second-order data. Parallel factor analysis and multivariate curve resolution-alternating least-squares were used for obtaining the spectral profiles of sample components and concentration profiles as a function of pH, including provisions for managing rank-deficient data sets. An appropriately designed calibration with a nine-sample set of binary mixtures of standards, coupled to the use of the second-order advantage offered by the applied chemometric techniques, allowed quantitation of the analytes in synthetic test samples and also in commercial orange juices, even in the presence of unmodeled interferents (with relative prediction errors of 8.7% for benzoic acid and 2.5% for sorbic acid). No prior separation or sample pretreatment steps were required. The comparison of results concerning commercial samples with a laborious reference technique yielded satisfactory statistical indicators (recoveries were 99.0% for benzoic acid and 101.4% for sorbic acid).

[Assessment of urinary trans, trans-muconic acid as a biomarker of exposure to benzene]. / Avaliação do ácido trans, trans-mucônico urinário como biomarcador de exposição ao benzeno.

OBJECTIVE: To assess the use of trans, trans-muconic acid as a biomarker of occupational exposure to benzene. METHODS: Trans, trans-muconic acid in urine samples of exposed (exposed group, n=36) and non-exposed (non-exposed group, n=116) workers to benzene. Urinary levels of trans, trans-muconic acid were quantified by high-performance liquid chromatography. The study sample consisted of subjects exposed to benzene in an oil refinery in Belo Horizonte, Brazil. Non-parametric statistical analysis was carried out using Kruskall-Wallis test, Mann-Whitney test and Spearman correlation at p<0.05. RESULTS: Workers were exposed on average to benzene levels of 0.15 +/- 0.05 mg/m3 (0.05 ppm) and they showed a urinary trans, trans-muconic acid mean value of 0.19 +/- 0.04 mg/g of creatinine. The reference value range of trans, trans-muconic acid in non-exposed subjects was 0.03 to 0.26 mg/g of creatinine (mean 0.10 +/- 0.08 mg/g of creatinine). There was seen a statistical difference between trans, trans-muconic acid levels in urine samples from exposed and non-exposed groups. There was no correlation between urinary trans, trans-muconic acid and air benzene levels. There was no correlation between urinary trans, trans-muconic acid levels in the exposed group and smoking. Alcohol consumption up to 48 hours before sampling procedure showed no effect on trans, trans-muconic acid levels in both exposed and non-exposed groups. There was however a correlation between age (range 18 to 25 years) and urinary metabolite levels in the latter group. CONCLUSIONS: The results show that it is important to evaluate the effect of age and smoking habits on urinary trans, trans-muconic acid levels.

Spectrophotometric determination of sorbic and benzoic acids in fruit juices by a net analyte signal-based method with selection of the wavelength range to avoid non-modelled interferences.

Sorbic (SOR) and benzoic (BEN) acids were determined in fruit juice samples by using a net analyte signal-based methodology named HLA/GO (an hybrid linear analysis presented by Goicoechea and Olivieri) applied to spectroscopic signals. The calibration set was built with several fruit juices in order to take into account the natural variability and concentrations of both analytes covering the range usually present in commercial samples. Relative errors of prediction (REP %) of 3.6 and 5.2% were calculated for SOR and BEN respectively. Several figures of merit were calculated-sensitivity, selectivity, analytical sensitivity, and limit of detection. The method is quantitative, with reasonably good recoveries and excellent precision (less than 1%). Wavelength selection was applied, based on the concept of net analyte signal regression, and it allowed us to improve the method performance in samples containing non-modelled interferences, e.g. fruit juices different to those used to build the calibration model.

Estimates of the mean per capita daily intake of benzoic and sorbic acids in Brazil.

The daily intakes of benzoates and sorbates from selected food categories were estimated in Brazil in 1999. The Budget method was used as a first screening procedure for the estimation of the safety aspects of the maximum permitted levels of benzoates and sorbates established by the Brazilian food legislation. This screening indicated that benzoates should be further investigated. In a second step, the daily intakes of these preservatives were assessed by combining measured levels of these additives with national food consumption data derived from a household economic survey and a packaged good market survey. Benzoate and sorbate levels in soft drinks, fruit juices, margarine, yoghurt and cheese were determined by HPLC with a photodiode array detector (detection at 228 nm for benzoic acid, 260 nm for sorbic acid). The estimated intakes of benzoates and sorbates for the average consumer were below the ADIs, ranging from 0.3 to 0.9 and 0.2 to 0.3 mg kg(-1) body weight, respectively. Soft drinks were identified as the main source of benzoates representing >80% of the estimated intake.

Capillary electrophoresis determination of urinary muconic acid as a biological marker for benzene in cigarette smoke.

trans,trans-Muconic acid (MA), a benzene metabolite in urine, has currently been indicated as a biological marker for benzene in cigarette smoke. The available methodologies for MA present a few shortcomings, such as lack of specificity and labor-intensive sample pretreatment. In this work, a capillary electrophoresis method for separation, identification, and quantification of urinary muconic acid has been implemented. The electrolyte consisted of a 60-mM phosphate buffer solution (pH 7), containing 0.1 mM cetyltrimethylammonium bromide (CTAB) as an electroosmotic flow modifier. Urine samples from nonsmokers and smokers were filtered through a 0.22-micron membrane prior to injection in a 75 microns i.d. x 80 cm capillary. The analysis was conducted under constant voltage conditions of -30 kV and direct UV detection at 262 nm. The detection capability of the electrophoresis system was enhanced by employing a high-sensitivity optical cell, positioned at 60 cm from the injection port. The CE methodology presented an overall analysis time of less than 10 min, with 5 min spent for capillary conditioning and approximately 5 min for run completion. The method was found to be sensitive for the determination of MA down to 25 micrograms/L, with a percentage recovery of 100 +/- 8%, and suitable for discriminating urinary MA from nonsmokers and smokers.

Acidos grasos esenciales en la producción actual de oleaginosas de la República Argentina: posibilidades futuras de diversificación / Essential fatty acids in the present vegetable oils production of the República Argentina: future possibiities in the diversification trends production

Se presenta un resumen de los logros alcanzados durante casi 50 años en un tema fundamental del conocimiento de las características de composición acídica de aceites vegetales de producción masiva en la república Argentina. Su desarrollo, en parte coincidente con la evolución del conocimiento analítico, ha sido de utilidad a la nutrición, normalización, legislación alimentaria, tecnología, uso y contralor de aceites vegetales y de pulpa de frutos. El progreso observado en los avances de modernas técnicas de la Biotecnología tiende a una apertura en la diversificación de la producción

Acidos grasos esenciales en la producción actual de oleaginosas de la República Argentina: posibilidades futuras de diversificación / Essential fatty acids in the present vegetable oils production of the República Argentina: future possibiities in the diversification trends production

Se presenta un resumen de los logros alcanzados durante casi 50 años en un tema fundamental del conocimiento de las características de composición acídica de aceites vegetales de producción masiva en la república Argentina. Su desarrollo, en parte coincidente con la evolución del conocimiento analítico, ha sido de utilidad a la nutrición, normalización, legislación alimentaria, tecnología, uso y contralor de aceites vegetales y de pulpa de frutos. El progreso observado en los avances de modernas técnicas de la Biotecnología tiende a una apertura en la diversificación de la producción