采用新型固相萃取柱快速测定食用植物油中苯并［a］芘

研究了Bond Elut ENV新型固相萃取柱在食用植物油中苯并[a]芘快速检测中的应用,建立了快速测定食用植物油样品中苯并[a]芘残留量的固相萃取/液相色谱/荧光检测法。样品用正己烷溶解,固相萃取净化,SUPELCOSILTMLC-PAH(25 cm×4.6 mm,5μm)色谱柱分离,以乙腈-水(95∶5)为流动相,荧光检测(λex=297 nm,λem=408 nm),外标法定量。苯并[a]芘的检出限为0.3μg/kg,在1.0～50.0μg/L范围内线性关系良好,相关系数为0.999 6,方法的回收率为79%～102%,相对标准偏差不高于9.4%。该方法准确、实用、简便、快速,在食用植物油的苯并[a]芘残留量检测方面有广泛的应用前景。     

Selection of SPE cartridge for automated solid-phase extraction of pesticides from water followed by liquid chromatography-tandem mass spectrometry

In environmental analyses there is an ever-increasing need to develop simple and sensitive multi-residue methods. In many agricultural regions, there is particular concern of the potential for pesticides to enter rivers and other waterways. This study reports on the development and validation of a multi-residue method of analysis for 30 pesticides in water samples using solid-phase extraction (SPE) followed by LC-MS/MS. The electrospray and MS/MS parameters were optimised for each pesticide, including capillary voltage, collision-induced dissociation voltage, and selection of a precursor ion and two product ions. A variety of SPE sorbents were tested for sample pre-concentration, including numerous polymeric based phases. Bond Elut PPL and Oasis HLB were the only phases capable of retaining the majority of the target analyte classes in a single method. An off-line pre-concentration method using a Gilson Aspec system was optimised using the Bond Elut PPL cartridges, with a concentration factor of 25 producing limits of quantitation in the order of 6–100 ng/L. Excellent linearity (r ² > 0.9), precision (<20%) and recovery (>60%) was obtained for nearly all of the analytes, covering a wide variety of chemical and physical properties. This is the first study to fully validate Bond Elut PPL cartridges for use in multi-residue pesticide analysis.     

Evaluation and optimization of solid adsorbents for the sampling of gaseous methylated mercury species

This study evaluates the suitability of commercially available adsorbents for the measurement of gaseous organic mercury species namely monomethylmercury (MMHg) and dimethylmercury (DMHg).