Studies And Applications Of Determining Organic Compounds In Pyrotechnic Composition By Chromatography

The firework is wildly favored due to its brilliant visual enjoyment and expression for sweet wishes, however, the security and environmental problems,which are from setting off fireworks should not be neglected too. Essentially, the drawbacks of fireworks are ascribed to choice of pyrotechnic compositions. In recent years, the requirements for fireworks are getting stricter at home and abroad. The establishment of a fast, simple and accurate detection method will contribute not only to the further study of pyrotechnic compositions but also to the manufacturing supervision of fireworks industry. In addition, advanced detection methods can provide support to break technical barrier.Through reviewing the literatures and date both home and abroad, the thesis established methods with high performance liquid chromatogram and capillary gas chromatography according to the properties of organic components which may be used in pyrotechnic compositions, such as gallic acid, picric acid, hexachlorobenzene, and hexachloroethane. These fast, simple and accurate methods are suitable to analysis the organic components aforementioned in pyrotechnic compositions. This thesis is consisted of four chapters and major contents are showed as following:1. First, the pyrotechnic compositions used in fireworks and combustion characteristics were summarized. Second, a detailed description about gallic acid, picric acid, hexachlorobenzene and hexachloroethane was presented. Last, the analysis and detection methods of pyrotechnic compositions were mainly introduced.2. A high performance liquid chromatography (HPLC) method was developed for the determination of gallic acid in Pyrotechnic composition. The HPLC separation was performed on a Zorbax Eclipse XDB-C₁₈ column with a gradient elution program of methanol- 0.1%acetic acid solution as the mobile phase at the flow rate of 1.0 mL/min and 25℃. The detection wavelength was 274 nm. There were good linear relationships between the mass concentrations and the peak areas of gallic acid in the range of 0.5²0.0μg/mL( r=0.9999 ). The recoveries were 87.0¹04.5% with the relative standard deviations of 1.2⁶.4%.3. A high performance liquid chromatography (HPLC) method was developed for the determination of picric acid in Pyrotechnic composition. With a elution program of methanol-0.1% acetic acid ( v/v = 55/45 ) solution as the mobile phase at the flow rate of 0.8 mL/min and 40℃. The detection wavelength was 355nm.There were good linear relationships between the mass concentrations and the peak areas of picric acid in the range of 0.5²0.0μg/mL(r = 0.9998).The recoveries were 84.0⁹2.0% with the relative standard deviations of 2.1⁵.7%. The method is quick, simple and accurate. It can be used for the determination of picric acid in Pyrotechnic composition.4. A method of simulataneous determination of Hexachlorobenzene and Hexachloroethane in Pyrotechnic composition by capillary gas chromatograph (GC) was developed. The hexachlorobenzene and hexachloroethane were extracted from the sample with n-hexane, and the extract was cleaned up using oil of vitriol. Then the determination was performed on a GC equipped with an hydrogen flame ionization detector (FID). The retention time was used for qualification and the external calibration standard was used for quantitation. The result obtained showed that there were good linear relationships in the range of 5.195²07.8μg/mL for hexachlorobenzene and 5.750²30.0μg/mL for hexachloroethane. The recoveries were 79.9%¹01.3% and 83.3%⁹7.9%with the relative standard deviations of 1.1%⁵.2% and 0.7%².7%in different levels. The method was corroborated by GC-MS; it's simple, rapid and accurate.