基于纳米纤维的富集作用,建立了血浆中5-羟色胺(5-HT)的柱前衍生高效液相色谱-电化学检测(HPLC-ECD)分析方法。用10%(v/v)高氯酸溶液沉淀血浆蛋白,离心后取上清液,用0.1 mo l/L的四苯硼酸钠溶液调节pH值至8.5,加入衍生剂邻苯二甲醛溶液于30℃衍生4 min,经纳米纤维固相萃取柱净化富集后,以pH 5.4的0.05 mo l/L磷酸二氢钾缓冲液(含0.25 mmo l/L乙二胺四乙酸)-甲醇(60∶40,v/v)为流动相在C18色谱柱(150mm×4.6 mm,5μm)上进行分离,进样量为20μL。结果表明,在高、中、低3个加标水平下,血浆中5-HT的加标回收率为95.6%～101.4%,日内与日间相对标准偏差均小于5%(n=3)。方法的定量线性范围为5～500μg/L,检出限为1μg/L。该方法操作简单、快速,具有较高的灵敏度和较高的重现性,能够用于血浆中5-HT的含量测定。
A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas chromatography-flame ionization detector （ GC-FID ）. Conditions for obtaining optimum extraction efficiency such as extraction solvents, morphologies of adsorbent, ion strength and pH were investigated and optimized in detail. Under the optimized conditions, the limits of detection （LODs） found for dibutyl phthalate （DBP） , butyl benzyl phthalate （BBP）, diethyl hexyl phthalate （DEHP） and di-n-octyl phthalate （DNOP） were 50, 25, 50 and 25 ng/g, respectively. Good linearity of four PAEs was achieved in the range of 50 to 4 000 ng/g. The proposed method was applied for analyzing different kinds of fat-containing samples. PAEs in commercial fat-containing samples can be highly extracted by a packed solid-phase extraction column of 5 mg polystyrene （ PS） nanofibers. The satisfactory average recoveries were obtained in the range of 96. 7% to 102. 3% , and the relative standard deviations （RSDs） below 5% were achieved. The proposed method reduces the organic solvent consumption, the complex and tedious procedures for sample pretreatment, and achieves high sensitivity and reproducibility for the investigated PAEs.
A novel method for sampling and enriching organic volatile contaminants in the vacuum environment combined with qualitative analysis based on the vacuum simulation test is proposed. A nanofiber is used as absorbent to collect the organic volatile contaminants in the vacuum environment and then eluted by methanol. The eluent is analyzed by gas chromatography （ GC ） and gas chromatography-mass spectrometry （GC/MS） to identify the composition of the organic contaminants. The nanofiber is composed of polystyrene and it is prepared by electrospinning. Before being used, the nanofiber is processed by ultrasound in ethanol for 15 min to remove some impurities and dried in an oven at 60 ℃, and then 10 mg of the nanofiber is wrapped in a thermoplastic polyester fabric pocket. The vacuum pump oil and di-iso-decyl phthalate （DIDP） are chosen as absorbates to test the absorbent performance of the nanofiber in the vacuum environment. Experiments are performed under the pressure of 10-4 and 103 Pa, respectively. It is shown that the nanofiber-based enrichment device can be used to adsorb the organic contaminants in the vacuum simulation environment.
