Rapid screening of illicit additives in weight loss dietary supplements with desorption corona beam ionisation (DCBI) mass spectrometry

Desorption corona beam ionisation (DCBI), the relatively novel ambient mass spectrometry (MS) technique, was utilised to screen for illicit additives in weight-loss food. The five usually abused chemicals – fenfluramine, N-di-desmethyl sibutramine, N-mono-desmethyl sibutramine, sibutramine and phenolphthalein – were detected with the proposed DCBI-MS method. Fast single-sample and high-throughput analysis was demonstrated. Semi-quantification was accomplished based on peak areas in the ion chromatograms. Four illicit additives were identified and semi-quantified in commercial samples. As there was no tedious sample pre-treatment compared with conventional HPLC methods, high-throughput analysis was achieved with DCBI. The results proved that DCBI-MS is a powerful tool for the rapid screening of illicit additives in weight-loss dietary supplements.     

A comparative study of the effects of chemical additives on the suppression efficiency of water mist

This paper reports the results of a comparative study of the effects of various salt additives on the flame extinguishing efficiency of fine water sprays. The relative suppression efficiencies are gauged by comparing the extinguishment time of a heptane flame. Preliminary tests are performed in a reduced scale cup-burner; major results are obtained using the closed reduced compartment set-up.The addition of NaCl, KCl or KHCO₃ resulted in large improvements of the suppression efficiency of the water mist. Potassium compounds show the greatest effect as 10% solution of KHCO₃ reduces the average extinction time by up to 96% compared to pure water. The other additives tested have a less noticeable effects, with aqueous solutions of MnCl₂, ZnCl₂ and CuCl₂ showing minimal improvement over water, whereas (NH₄)₂HPO₄, (NH₂)₂CO and FeSO₄·7H₂O actually increasing the time taken to extinguish the flame.     

Synergistic effects of buffer layer processing additives for enhanced hole carrier selectivity in inverted Organic Photovoltaics

Solution based inverted Organic Photovoltaic (OPVs) usually use Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) derivatives combined with pristine processing additives as hole selective contact on top of the hydrophobic conjugated polymer:fullerene active layer. In this study, PEDOT:PSS based hole selective contact is treated with two different boiling point additives, 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol ethoxylate (Dynol) and Zonyl FS-300 fluorosurfactant (Zonyl). Although corresponding inverted OPVs using the above PEDOT:PSS:Additives show similar power conversion efficiency (PCE) values, the mechanisms of their implementation on inverted OPV operation are not identical. By understanding the synergistic effects of PEDOT:PSS processing additives on the hole selectivity of inverted OPVs we demonstrate a novel combination of PEDOT:PSS additives mixture as an effective route to further increase the hole selectivity, reliability andpower conversion efficiency of inverted OPVs.     

改性玉米须纤维及其对土碱中砷(Ш)的吸附

研究了用柠檬酸和三氯硫磷改性的玉米须对食品添加剂土碱中砷(Ш)的吸附工艺。结果表明,改性玉米须纤维(F1和F2)表面疏松、多孔,负电子基团含量增加,增强了与砷(Ш)配位结合的能力。最佳条件下,与对照组天然玉米须纤维(FN)相比,F1和F2的脱砷率分别提高了2.89倍和1.95倍,FN、F1和F2处理过的土碱回收率可达到96.85%、94.32%和95.45%,该研究对土碱中砷含量控制具有重要意义。     

低挥发环保增塑剂对苯二甲酸二（2⁃丙基庚）酯的应用研究

以对苯二甲酸和2?丙基庚醇为原料,在钛酸异丙酯为催化剂的条件下制备对苯二甲酸二（2?丙基庚）酯（DPHTP）,并将DPHTP作为增塑剂用于制备聚氯乙烯（PVC）柔性薄膜,与市售DOP和DOTP进行应用性能的比较。通过傅里叶变换红外光谱和核磁共振氢谱对产物进行结构分析;通过热失重分析、拉伸测试、耐迁移测试和耐挥发性测试等比较DPHTP、DOP以及DOTP增塑的PVC薄膜在力学性能等方面的差异。结果表明,相比DOP和DOTP,DPHTP具有更低的挥发性,其增塑的薄膜有着更优异的热稳定性以及更高的体积电阻率;其中,DPHTP的加热减量为0.031 90 %,DPHTP增塑的薄膜的热失重5 %的温度为272 ℃,体积电阻率为6.5×10⁹ Ω·m;DPHTP具有更低的挥发性且可以赋予PVC材料优异的电绝缘性能,在包装材料和电线电缆行业具有广阔的开发前景。     

分子模拟技术在钻井液研究中的应用

分子模拟是一门新兴的计算化学技术,在辅助分子设计、结构解析、物性预测等方面的作用日益显著,已广泛应用于石油、化工、食品、制药、航空航天等工业领域,而该技术用于钻井液研究的报道较少。介绍了分子模拟技术在与钻井液相关的黏土矿物水化膨胀机理及黏土稳定剂设计、钻井液用表面活性剂,如泡沫剂、乳化剂等以及高分子如聚丙烯酰胺、天然高分子淀粉、木质素、树枝状高分子和环境响应型高分子研究中的应用。目前主要是利用分子力学、分子动力学等方法,通过模拟计算单个分子或分子体系的性质如结构、构象、热力学特性、相态转变等,从而进行钻井液处理剂理论模型建立、分子结构设计、合成路线优化、作用过程演示、实验现象解析等方面的研究工作。最后指出了分子模拟技术在钻井液处理剂研究领域推广应用存在的困难和发展前景。     

添加剂对高MgO烧结矿中铁酸钙生成的影响

高铝铁矿在高炉中用量的逐年增加,带来了高炉炉渣变稠、脱硫困难等一系列问题。生产高Mg O烧结矿成为解决高炉炉渣性质的有效途径之一。但是,烧结料中Mg O质量分数过高会导致烧结过程中黏结液相量减少,带来烧结矿强度降低的新问题。主要尝试向烧结料中配加少量的低熔点添加剂,以促进烧结过程中铁酸钙生成,拓宽改善烧结矿强度的思路。试验选择了B2O3、Ca Cl2和Na2Si O3为添加剂,配入高Mg O、高Al2O3烧结料进行烧结,通过对试样的XRD衍射分析、观察矿相结构等,研究添加剂对烧结过程的影响。结果表明,加入这3种低熔点添加剂,均能促进铁酸钙形成,但是影响程度不同。当Mg O质量分数为4%时,B2O3、Ca Cl2和Na2Si O3配入量(质量分数)分别为0.094%、0.470%和0.470%,可形成最多的铁酸钙,较少的加入量有利于铁酸钙形态向针状发展。Mg O质量分数较高时,液相生成有助于赤铁矿向磁铁矿转变。     

聚乙烯醇薄膜降解菌的筛选及助剂的影响研究

利用聚乙烯醇(PVA)为唯一碳源的筛选培养基对PVA包装薄膜工厂排污口处的活性污泥进行筛选,并研究薄膜助剂对PVA降解性的影响。通过透明圈实验对菌株进行筛选,并经形态学及显微镜观察进行初步鉴定。从定性和定量角度,分别利用透明圈实验和紫外分光光度法研究薄膜助剂对PVA降解性的影响。结果表明:10株PVA降解菌中降解效果最佳的菌株XP-02鉴定为青霉菌;研究还发现,当PVA包装薄膜中的助剂浓度为0.05 g/L时,均能提高PVA的降解效果。其中,PVA包装薄膜中添加增塑剂(聚乙二醇)、表面活性剂(十二烷基苯磺酸钠)、乳化剂(吐温-80)可以使PVA的降解率分别提高5.01%,8.67%,11.21%。通过在PVA包装薄膜中添加适量聚乙二醇、十二烷基苯磺酸钠、吐温-80的可以提高PVA的生物降解率,但各组分最适比例还需要进一步研究进行确定。     

高效液相色谱法测定减肥类保健品中非法添加剂

通过用高效液相色谱法建立减肥类保健产品中非法添加剂盐酸西布曲明、酚酞、比沙可啶及布美他尼4种减肥化学成分的快速检验方法。本法盐酸西布曲明含量在0.6156~7.6950μg间具有良好的线性关系(R=1.0000),平均回收率为100.82%,RSD为0.29%(n=6);酚酞含量在0.2166~2.7075μg间具有良好的线性关系(R=0.9999),平均回收率为100.30%,RSD为0.16%(n=6);比沙可啶含量在0.4368~5.46μg间具有良好的线性关系(R=0.9999),平均回收率为99.26%,RSD为0.28%(n=6);布美他尼含量在0.4208~5.26μg间具有良好的线性关系(R=1.0000),平均回收率为100.46%,RSD为0.17%(n=6)。     

车用汽油中非法添加物检测方法研究进展

介绍了车用汽油中常见的非法添加物以及其带来的危害,综述了国内近三年车用汽油中常见的非法添加物的定性定量分析方法,其中包括气相色谱法、二维气相色谱法、气相色谱-质谱联用法、中红外光谱法等法,以期为今后车用汽油中违规添加国家车用汽油标准中禁止人为加入的有害添加物提供检验方法和限制值。