Plant hormones are of vital importance for normal functioning of plants that coordinate the growth and development of plants with response to the environment. Plant hormones are difficult to analyze because they occur in very low amounts in plant extracts which are very rich in interfering substances, especially secondary metabolites. To cope with this problem the plant extract must undergo several purification steps using unrelated separation mechanisms in order to increase orthogonality and purification efficiency (Dobrev et al., 2005). High performance liquid chromatography and Gas liquid chromatography are frequently used in the purification and quantification of plant hormones like Abscisic acid, Indole acetic acid etc.
A method for estimation of Abscisic acid in Arabidopsis thaliana includes an extraction of plant tissues with acetone/water/acetic acid (80:19:1, v/v), evaporation of the extracts and finally injection into the liquid chromatography-electrospray ionization tandem mass spectrometry (LC–ESI–MS–MS) system in multiple reaction monitoring (MRM) mode (Carbonell and Jáuregui, 2005).
A novel metabolic profiling approach to the analysis of acidic phytohormones and other metabolites based on a simplistic preparation scheme and analysis by chemical ionization-gas chromatography/mass spectrometry has also been developed (Schmelz et al., 2004). But Current metabolomic approaches are able to quantify highly abundant primary and secondary metabolites but do not perform well at detecting trace levels of phytohormones.
Separate profiling methods, with comparatively more elaborate sample preparation procedures, are now making phytohormone profiles accessible using trace analysis chemical ionization GC/MS techniques. Using LC/MS detection, a significant phytohormone profiling advance was recently achieved (Chiwocha et al. 2003).