| Solid-phase microextraction (SPME) was developed by Pawliszyn and co-workers in 1989. It successfully overcomes the inherent shortcomings of conventional sample preparation methods by integrating a number of sample handling operations such as extraction, preconcentration, and sample introduction for instrumental analysis into a single step. Within the past few years, it has been widely used for the pretreatment of complicated matrices in environmental, food and drug.In this article, a series of applications in food were carried out by our lab-made SPME device. Moreover, we made some improvements at the basic of traditional SPME divice and evaluation its characteristics.A headspace solid-phase microextraction (HS-SPME)/gas chromatographic technique for the quantitative analysis of polycyclic aromatic hydrocarbons was developed in this study. The extraction parameters such as extraction temperature, extraction time, salt concentration and stirring speed were optimized. The optimized extraction protocol was as follows:60℃of the extraction temperature,40 min of the extraction time, and 60 mg/g NaCl in concentration with agitation at 600 r/m, pH 5.0. Under the optimized conditions, a mini validation was performed and the following parameters were determined:limit of detection, precision, recovery and linearity. The linearity was very good in the considered concentration ranges (r>0.9964). Average recoveries ranged from 81.07% to 107.5% and showed good accuracy for the proposed analytical method. And relative standard deviation (RSD) for five replicate analyses was found to be less than 11.6%. The limit of detection (LOD) ranged from 0.04-2.32 ng/g for all compounds. The method was successfully applied for headspace analysis of nine vegetables samples.A headspace solid-phase microextraction (HS-SPME), in conjunction with gas chromatography using a novel sol-gel calix[6]arene-contained fiber for the determination of phthalate acid esters (PAEs) in non-alcoholic beverages is described for the first time. A Taguchi's L25 (56) orthogonal array experimental design was introduced to optimize the extraction parameters such as extraction temperature, extraction time, salt concentration and stirring speed. The optimized conditions were as follows:100℃of the extraction temperature,50 min of the extraction time, and 180 g/L NaCl in concentration without agitation. Under the optimized conditions, the method showed linear response of three to five orders of magnitude with correlation coefficients (r) better than 0.995. Owing to the good selectivity and high sensitivity of this fiber to PAEs, the extraction was carried out in real beverage matrix and low detection limits of 0.015-0.298μg/L were achieved. The recoveries of standard addition tests amounted to 87.9%-108.3% and the relative standard deviation values varied from 9.62% to 15.2%. The method was applied to the analysis of 12 kinds of beverages and bis-2-ethylhexyl phthalate was the sole analyte detected in these samples.An improved SPME device based on sol-gel hydroxy-terminated silicone oil (OH-TSO) coated multifibers (3 fibers) was constructed. The multifibers provided larger extracion capacity compared to a single fiber without increasing the extraction time. This result was explained by the analysis of benzene substitutes (BTEX), polycyclic aromatic hydrocarbons (PAHs) and phthalate acid esters (PAEs). Its extraction amount was 2.61-3.28 times larger than that by a single fiber for BTEX under the same conditions. For PAHs and PAEs, the multiplying factor was 1.56-3.11 and 2.19-7.41, respectively. The linearity obtained by the multifibers was much wider than that obtained by the single fiber and the limit of detection was much lower to each of the analytes. |
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