【作者】 孟洪波；

【导师】 郭灿雄；

【作者基本信息】 北京化工大学 ， 应用化学， 2008， 硕士

【摘要】 在爆炸现场,对爆炸残留物进行检测,对鉴别无机爆炸物的种类是非常重要的。本文研究了用便携式非抑制型离子色谱仪岛津PIA-1000对爆炸物残留中的无机阴、阳离子进行了同时分离和检测。在最优的色谱条件下,16 min内可对8种无机阴阳离子(Cl^-,NO₂^-,NO₃^-,ClO₃^-,SO₄^2-,K⁺,Na⁺,NH₄⁺)进行同时分离和检测,并将此方法应用到实际爆炸物样品的检测中,可以满足对现场爆炸物残留的无机阴、阳离子的定性、定量分析。在本试验中主要考虑到了以下几个因素:1、选择合适的淋洗液。所选择的淋洗液必须同时具有疏水性功能基团和亲水性功能基团,与阴离子交换柱和阳离子交换柱的功能基团相结合,对无机阴、阳离子进行离子交换作用。本实验中选择了邻苯二甲酸作为淋洗液。2、考虑淋洗液的pH值对整个分离过程的影响。淋洗液邻苯二甲酸有两个不同的pKa值,在不同的pH值下,它会表现出不同的离子形态,拥有不同的离子交换强度,必须选择了合适的pH值,使淋洗液有合适的离子强度。3、考虑了邻苯二甲酸的浓度对分离过程的影响。随着浓度的增加,可交换的离子增加,离子交换能力变大,但随着浓度的增加,背景电导也增加,降低了分析的灵敏度。因此必须找到一个合适的浓度,使淋洗液拥有足够的离子交换能力和灵敏度。4、研究了有机添加剂乙腈在淋洗液中的含量对分离过程的影响。淋洗液中乙腈含量增加,可以增加淋洗液的疏水性,乙腈还可以占据柱子固定相中的疏水空腔,减少目标离子和柱子的非离子交换作用,从而改善目标离子的峰形,分离度和保留时间。5、研究了阴阳离子交换柱的连接顺序对整个分离过程的影响。最后,得到了同时对8种无机阴、阳离子分离的最佳条件是:邻苯二甲酸浓度3.5 mM,pH=4.0,乙腈加入量2%,柱子连接顺序为阴离子交换柱-阳离子交换柱。在最优的色谱条件下,可以在16 min内对8种无机阴、阳离子进行完全的分离,并把此方法应用到实际爆炸物样品的检测中。。更多还原

【Abstract】 The determination of inorganic anions and cations in explosive residues at explosion plot,which was very important to decide explosives types.In our research,we simultaneously determinate and separate eight inorganic ions(Cl^-, NO₂^-,NO₃^-,ClO₃^-,SO₄^2-,K⁺,Na⁺,NH₄⁺)within 16min.Several factors were considered as below:1.The eluent of both hydrophobic group and hydrophilic group should be chosen.Phthalic acid has been chosen as the eluent to determine anions and cations simultaneously,considering that phthalic acid contains strong hydrophobic benzene ring and hydrophilic hydroxyl group.Therefore,the phthalic acid was chosen became eluent.2.The pH of eluent was also the important factor effect the ion-exchange ability of eluent.Under different pH,the eluent have different ionic species and different ion-exchange ability.In the end,the pH=4.0 was chosen in the following experiments.3.The effect of phthalic acid concentration in eluent on the retention time of anions and cations was investigated as well.The increase of the phthalic acid concentration of the phthalic acid caused decrease in the sensitivity of conductivity detection.Therefore,the low phthalic acid concentration should be chosen.Taking the retention time,the resolution and the sensitivity into consideration,the optimal concentration of phthalic acid was 3.5 mM.4.The influence of acetonitrile on the retention time of anions and cations was also investigated in the present work.Acetonitrile can occupy the hydrophobic position of ion exchange resin,and reduce the non-ion exchange reaction of target inorganic ions and ion exchange resin,at the same time; acetonitrile possesses hydrophobic character,and increase the hydrophobicity of eluent.5.The order of the columns connected was considered in our studies.In the end,simultaneous determination of inorganic anions and cations by connecting anion-exchange/cation-exchange columns was obtained within 16min using a eluent composed of 3.5 mM phthalic acid,2%acetonitrile,pH= 4.0.更多还原