فهرست مطالب کبری مردی

In this study, an efficient and green technique based on ultrasound-assisted extraction was developed for separation and determination of some components of double base solid propellant (DB propellant) by high performance liquid chromatography with UV detection (HPLC-UV-Vis). The optimum extraction conditions with respect to maximum recovery for target analytes were achieved at 120 min, with the power of 800 W for ultrasonic waves and dichloromethane as an extraction solvent for 0.5 gr of DB propellant sample and the recoveries for all component was near to 100%. The results of this investigation under optimum conditions were compared with the result obtained by the Soxhlet extraction method as a routine sample preparation method for DB propellant samples. The results show that the developed method is much faster and sufficient than the traditional Soxhlet extraction method. So, the developed UAE-HPLC-UV method can be used as a rapid and sensitive method for the determination of DB propellants’ constituents.

In this work, a simple and selective method for the determination of nitroglycerine (NG) in double base solid (DB propellants) has been developed and validated. The proposed method is based on alkaline hydrolysis of NG and followed by colored reaction of released nitrite ion with p-nitroaniline in the presence of diphenylamine in acidic media, producing azo dye. The effect of important parameters on the solution absorbance was investigated and optimized. Under optimal conditions, at λmax= 534 nm, the linear range of determination of nitroglycerine was 0.2-5.0 µg mL-1 with detection limits of 0.1 µg mL-1. The proposed method was successfully applied to the determination of nitroglycerine in DB propellants with good recoveries ranged from 98-105 % and RSD less than 2.5 %. the results were statistically compared with those obtained by the by military standard 286 method using t- and F-tests. There was no significant difference between the mean values and the precisions of the two methods at the 95% confidence level. The results showed that the proposed method offers an accuracy and reliable approach for the determination of nitroglycerine in DB propellants, and can be suggested as a routine method in military quality control laboratories.

In this study, an efficient and green technique based on ultrasound-assisted extraction was developed for separation and determination of some components of double base solid propellant (DB propellant) by high performance liquid chromatography with UV detection (HPLC-UV-Vis). The optimum extraction conditions with respect to maximum recovery for target analytes were achieved at 120 min, with the power of 800 W for ultrasonic waves and dichloromethane as an extraction solvent for 0.5 gr of DB propellant sample and the recoveries for all component was near to 100%. The results of this investigation under optimum conditions were compared with the result obtained by the Soxhlet extraction method as a routine sample preparation method for DB propellant samples. The results show that the developed method is much faster and sufficient than the traditional Soxhlet extraction method. So, the developed UAE-HPLC-UV method can be used as a rapid and sensitive method for the determination of DB propellants’ constituents.

2-methylaziridine (propylene imine) is widely used in the production of binding agents in the defence industry. Despite its importance, it is a highly volatile and toxic and can be easily released into the atmosphere during the production and usage causing environmental pollution. The International Agency for Research on Cancer (IARC) has classified it as a Group 2B, possible human carcinogen. So, regarding to the application of 2-methylaziridine in military industry and its toxicity, the determination of its trace amounts is very important in environment samples and industrial wastewater. In this paper, a novel method for preconcentration and spectrophotometric determination of trace amounts of 2-methylaziridine using dispersive liquid-liquid microextraction (DLLME) technique has been developed. This method is based on derivatization of 2-methylaziridine with Folin’s reagent (1,2-naphthoquione-4-sulphonic acid) and preparation of a hydrophobic product with a high molar absorption coefficient which can be preconcentrated and extracted with DLLME technique. Some important parameters of derivatization and microextraction were studied and optimized. Under the optimum conditions, the calibration graph was linear in the range of 10-800 ng mL-1 with detection limit of 5.0 ng mL-1 and relative standard deviation for seven replicate determinations of 2-methylaziridine at 100 ng mL−1 concentration level was calculated to be 1.92%. The proposed method was applied for the determination of 2-methylaziridine in natural water and wastewater samples. In addition, excellent agreement was observed between this proposed method and the standard method.