离子色谱法同时分析无机爆炸物残留中的无机阴阳离子

发布时间：2018-04-17 08:32

本文选题：非抑制型离子色谱 + 同时分离　；参考：《北京化工大学》2008年硕士论文

【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~-,NO_2~-,NO_3~-,ClO_3~-,SO_4~(2-),K~+,Na~+,NH_4~+)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。。
[Abstract]:At the scene of the explosion, the detection of explosive residues is very important for the identification of inorganic explosives.In this paper, the simultaneous separation and determination of inorganic anions and cations in explosive residue by PIA-1000, a portable uninhibited ion chromatograph, were studied.Under the optimal chromatographic conditions, 8 kinds of inorganic anions, Cl-No _ 2H _ 2N _ 2H _ 2O _ 3H _ O _ 3H _ O _ 3H _ O _ 3H _ O _ 3O _ 3O _ 3O _ 3 / S _ 4T _ 4 can be separated and detected simultaneously within 16 min. The method has been applied to the detection of real explosives samples, and can satisfy the inorganic negative of explosive residue in the field, and can be applied to the detection of real explosive samples, and the method can be applied to the detection of practical explosives samples, and the method can be applied to the detection of explosives in the field.Qualitative and quantitative analysis of cations.The following factors have been taken into account in this experiment:1. Choose the appropriate eluent.The eluant must have hydrophobic and hydrophilic groups, which are combined with the functional groups of anion exchange column and cation exchange column to exchange inorganic anions and cations.In this experiment, phthalic acid was selected as eluent.2. The effect of pH value of eluate on the whole separation process was considered.Phthalic acid has two different pKa values. Under different pH values, phthalic acid has different ionic forms and different ion exchange intensities. It is necessary to select the appropriate pH value to make the eluent have appropriate ionic strength.3. The influence of phthalic acid concentration on the separation process was considered.With the increase of the concentration, the exchangeable ions increase and the ion exchange ability increases, but with the increase of the concentration, the background conductance also increases, which reduces the sensitivity of the analysis.Therefore, a suitable concentration must be found so that the eluent has sufficient ion exchange capacity and sensitivity.4. The effect of the content of acetonitrile on the separation process was studied.The increase of acetonitrile content in the eluate can increase the hydrophobicity of the eluate. Acetonitrile can also occupy the hydrophobic cavity in the stationary phase of the column and reduce the non-ion exchange between the target ion and the column, thus improving the peak shape of the target ion.Separation degree and retention time.5. The influence of the connection sequence of cationic ion exchange column on the whole separation process was studied.Finally, the optimum conditions for the separation of eight inorganic anions were obtained as follows: the concentration of phthalic acid was 3.5 mm ~ (-1) pH ~ (+) 4.0, the amount of acetonitrile was 2 ~ (th), and the column connection sequence was anion exchange column and cation exchange column.Under the optimum chromatographic conditions, eight inorganic anions and cations could be completely separated in 16 min, and the method was applied to the detection of real explosives.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：D918.91

【引证文献】