No abstract

A sensitive, selective, precise, and robust densitometric method for the analysis of nicotine (drug component of Nicotiana tabacum) in various tobacco products (TPS), including smoked (cigarette and beedi), sniffing (sniffing niswar), dipping (niswar), and chewing (gutka) tobacco brands, was developed and validated as per the ICH guideline. TLC glass plates, precoated with silica gel 60F-254, were used for the analysis. Densitometric analysis of nicotine was carried out in the absorbance mode at 262 nm. The mobile phase consisted of petroleum ether-acetone-diethylamine (7.6:2:0.4) v/v, and gave a sharp and symmetrical nicotine peak (R F = 0.57 ± 0.005) under saturated environment. Linear regression data (LRD) for the calibration curve showed a good linearity with r = 0.997 ± 0.0013. The method was validated for precision, recovery, and robustness. The limits of detection (LOD) and quantitation (LOQ) were found to be 3.15 and 9.54 ng per spot, respectively. Statistical analysis indicated that the method is reproducible and selective for the estimation of nicotine in various TPS.

Ascorbic acid was used as leaching agent to investigate the dissolution kinetics of natural magnesite ore. The effects of various reaction parameters such as acid concentration, liquid-solid ratio, particle size, stirring speed, and temperature were determined on dissolution kinetics of the magnesite ore. It was found that the dissolution rate increased with increase in acid concentration, liquid-solid ratio, stirring speed, and temperature and decrease in the particle size of the ore. The graphical and statistical methods were applied to analyze the kinetic data, and it was evaluated that the leaching process was controlled by the chemical reaction, that is, . The activation energy of the leaching process was found to be 57.244 kJ mol−1 over the reaction temperature range from 313 to 343 K.