大果白刺游离脂肪酸的柱前衍生高效液相色谱-荧光检测法分析

采用2-（11H-苯[a]咔唑）乙基对甲苯磺酸酯（BCETS）为柱前荧光衍生试剂,通过梯度洗脱使得18种脂肪酸在BDS-C8柱上得到良好的分离.方法应用于大果白刺不同部位中游离脂肪酸的分析,结果表明大果白刺的果皮果肉和叶子中均含有大量的不饱和脂肪酸,其总不饱和脂肪酸含量分别为70.74%和73.47%.大果白刺种子中不饱和脂肪酸的含量相对较少,仅占总脂肪酸含量的57.21%,其不饱和脂肪酸组成主要是C18∶1（油酸）和C18∶2（亚油酸）.其中,大果白刺的果皮果肉中,不饱和脂肪酸主要是C18∶1、C18∶2和C18∶3（亚麻酸）.其叶子中的不饱和脂肪酸主要是C18∶3,所占总脂肪酸比例为48.34%.首次对大果白刺中的脂肪酸进行了分析,可以为大果白刺在食品、药品中的进一步开发应用和质量控制提供一定的数据支持.     

Determination,aerobic biodegradation and environmental occurrence of aliphatic alcohol polyethoxylate sulfates (AES)

A new analytical method was developed for the routine specific determination of the anionic surfactant Alcohol polyEthoxylate Sulfate (AES) in environmental aqueous samples. An enrichment/fractionation of the target analytes in water samples was performed by solid-phase extraction (SPE) on graphitized carbon black (GCB) (recoveries: 90–103%), followed by hydrolysis/derivatization with fluorescent reagents and separation/detection by reversed-phase high performance liquid chromatography coupled with fluorescence (HPLC-FLD). The developed procedure was applied to the study of the aerobic biodegradation of AES under laboratory conditions and to a ten-month monitoring of AES, as well as of linear alkylbenzene sulfonates (LAS), nonylphenol polyethoxylates (NPE) and alcohol polyethoxylates (AE) surfactants, in the Po river (Northern Italy). The residual concentrations found in the river waters were compared and used for a preliminary estimation of the annual average loads of monitored surfactants in the Adriatic Sea.     

Strategies for the extraction of free and bound polycyclic aromatic hydrocarbons in run-off waters rich in organic matter

The objective of this study was to optimize and characterise extraction methods to examine the effects of wood ash application on polycyclic aromatic hydrocarbons (PAHs) concentrations in run-off waters for the evaluation of their distribution by storage in the different compartments (free and bound to dissolved organic matter, DOM), what influence their stability and persistence. The feasibility of solid phase extraction (SPE) and stir bar sorptive extraction (SBSE) for the determination of eight PAHs in run-off water samples has been evaluated. Both are appropriate to determine PAHs in run-off waters, but SPE is suitable for the determination of overall PAHs, while SBSE is used for the determination of free PAHs. The combination of both extraction techniques can then be used to estimate PAHs bound to DOM. Another approach based in the only use of SBSE is proposed for the estimation of all PAHs fractions (free, bound to DOM, and overall), once we are able to estimate the fraction percentage the free concentration represents. The percentage of free fraction was variable in the run-off waters with medium levels of DOM depending on the number of aromatic rings, molecular weight and water solubility of PAHs.     

Inter-laboratory validation of the fluorescent protein phosphatase inhibition assay to determine diarrhetic shellfish toxins: intercomparison with liquid chromatography and mouse bioassay

Toxic episodes of diarrhetic shellfish toxins (DSP) in shellfish harvesting areas have serious economic and public health implications, where fluorescent protein phosphatase inhibition assay (FPPIA) may be a highly useful tool for monitoring purposes. This paper presents results from the first inter-laboratory study to validate the assay. Three laboratories participated in the design and development of the inter-laboratory work. Standard solutions and spiked samples of the main toxin, okadaic acid, were used at the beginning of the validation exercise to avoid cross-inhibition of other toxins that would otherwise deteriorate the quantitative significance of the data. HPLC with fluorimetric detection of okadaic acid was also submitted to inter-laboratory validation to be subsequently used as a quantitative reference method. FPPIA results from spiked samples were free of systematic bias in any laboratory and determinations repeated over 3 days showed that the classic “repeatability” was the main within-laboratory source of variability (15-26% R.S.D. depending on the sample).After the inter-laboratory validation of both HPLC and FPPIA methods, 83 samples of mussel hepatopancreas collected during a toxic DSP episode were analyzed over 9 weeks. Toxic levels determined with FPPIA were in line with mouse bioassay results, highlighting the lack of false negative results of the FPPIA test: 98.7% of samples whose concentration of okadaic acid equivalents was over 0.8 μg/g hep., provided positive bioassay results within 24 h of observation time. The reliability and the quantitativeness of the FPPIA method in naturally contaminated samples was demonstrated by intercomparison with mouse bioassay and HPLC.     

Setup of an Ultrasonic-Assisted Extraction to Obtain High Phenolic Recovery in Crataegus monogyna Leaves

Hawthorn leaves are a rich source of phenolic compounds that possess beneficial activities for human health. Ultrasonic-assisted extraction (UAE) is an extraction technique frequently used for the isolation of phenolic compounds in plants. Thus, in this study, a Box–Behnken design was used to optimize UAE conditions such as the percentage of acetone, the extraction time and solvent-to-solid ratio (v/w) in order to obtain the maximum content of total compounds by Folin–Ciocalteu and the maximum in vitro antioxidant activity by DPPH, ABTS and FRAP assays in Crataegus monogyna leaves. The optimum conditions to obtain the highest total phenolic content and antioxidant activities were 50% acetone, 55 min and 1/1000 (w/v). A total of 30 phenolic compounds were identified and quantified in C. monogyna leaf extract obtained at these optimum UAE conditions. HPLC-MS allows the identification and quantification of 19 phenolic compounds and NP-HPLC-FLD analyses showed the presence of 11 proanthocyanidins. According to the results, the most concentrated phenolic compounds in C. monogyna leaf extract obtained at optimum UAE conditions were phenolic acid derivatives such as protocatechuic acid-glucoside, dihydroxy benzoic acid pentoside and chlorogenic acid, flavones such as 2″-O-rhamnosyl-C-hexosyl-apigenin, flavonols such as hyperoside and isoquercetin and proanthocyanidins such as monomer and dimer. As a result, the optimized UAE conditions could be used to obtain an extract of C. monogyna leaves enriched with phenolic compounds.