Principles and Practice of ABA Analysis - Abscisic Acid: Metabolism, Transport and Signaling - page 428

21.3 Summary
Since the isolation and characterization of ABA have been reported (Ohkuma
et al. 1963 ), many analytical systems for the precise and accurate identification
and quantitative determination of trace ABA has been developed for the bet-
ter understanding of the molecular mechanisms of ABA. Based on the literature
reviewed in this paper, a sum-up protocol for ABA analysis is given in Fig. 21.1 .
All of the current analytical techniques require prior preparation of highly puri-
fied extracts which are achieved by one or more steps. The pretreatment steps
should be minimized to curb matrix effect of interfering substances. Universal
and selective sample preparation techniques, including LLE, SPE, IAE, and MIP
extraction, have been successfully applied to separate and enrich ABA from plant
tissues. SPE benefits from low intrinsic cost, shorter processing time, low solvent
consumption, and simpler processing procedure, and becomes the most popular
method for fast and high-throughput purification of samples.
Immuno-based analytical methods depended on the antigen-antibody specific
interaction have high sensitivity and specificity for purification and detection of
ABA, but cross-reactions cause many problems. Biosensor, the real-time quanti-
fication approach, is somehow restricted by its limited reproducibility and short
service life. The capability of combination with GC or LC broadens detection with
mass spectrometry. Compared with other assays, the MS methods, which exhib-
its more advantages including high sensitivity, high selectivity, high-throughput
and excellent accuracy, have been proved to be a reliable tool for ABA analysis.
In particular, GC or LC coupled with tandem mass spectrometry not only signifi-
cantly improves the sensitivity but also provides structural information based on
Fig. 21.1 A typical sum-up
protocol for ABA analysis.
See detailed description in
the text