Chemometrics and Statistics coursework Essay Example | Topics and Well Written Essays - 2000 words

Chemometrics and Statistics coursework - Essay Example nce in pharmacological activities (Xu et al,2012).They are also known to be similar in terms of morphology, hence normally classified by experts or herb farmers. This process needs a long term experience and it is based on the judgment that is subjective. Furthermore, they tend to be fragile as well as very hard to be differentiated in cases when the aerial parts are missing. In regards to this, it is important to develop a method that could be able to differentiate this plants and the method which is not based on the plant appearance (Fan et al, 2006). There are previous methods that are used in the differentiation of AS and AH.They include gas chromatography coupled to mass spectrometry and relies on essential oils and X-ray fluorescence analysis (Su, 1999). In relation to these procedures, in the course of the isolation of the essential oils through either solvent extraction or hydro-distillation, it is seen to be tedious and there is a high consumption of a large volume of both the solvent and the sample (such as 50–100 g). Hence, at this point, it is important to have solvent-free, a simple and rapid sample pretreatment method like headspace sampling. Such technique has also the advantage whereby fewer samples is required (normally less than 1g) and the capacity of being automated through a commercialized sampling system Head space is a gas space in a chromatography vial located above sample. The component of the volatile sample usually diffuse into the gas phase and later if forms headspace gas. Therefore, headspace analytical technique involves the analyzing the components that are present in that gas. Â  Headspace G-C is the most appropriate in the analysis of volatiles that are very light in the given sample which can be partitioned efficiently into the headspace gas volume from the solid or liquid matrix sample. Higher boiling semi-volatiles and volatiles are known not to be detected in such a technique because in the gas headspace volume, they do