Analysis of Salicylic Acid in Tobacco Leaves Using Capillary Zone Electrophoresis with UV Detection

Abstract

A simple and inexpensive capillary zone electrophoresis (CZE) with UV detection method was used to determine salicylic acid (SA) and six structural analogs (benzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, acetylsalicylic acid, methyl salicylate, and jasmonic acid). All of the compounds were successfully separated within a migration period of 6 min, with a high number of theoretical plates (>37,000, calculated using the width at the base of the SA peak), in 20.0 mmol L−1 Na2HPO4/H3BO3 buffer (pH 9.0) containing 2.0% methanol and 2.0% acetonitrile. The regression line for SA was linear over the range 0.5–200 mol L−1. Both the intra- and inter-day precisions of the migration time (relative standard deviations, RSDs, 0.6% and 4.7%, respectively) and peak area (RSDs 0.9% and 7.3%, respectively) were acceptable. The proposed method was used to determine the SA concentrations in tobacco leaves (Nicotiana tabacum L.) from the Xanthi-nc (NN genotype) and the Nt-NahG mutant strains that had been irradiated with UV (254 nm) for 20 min and the ones that had not been irradiated. Rapid separation (<6 min), good reproducibilities (RSDs < 11.9%), and good recoveries (94.7% to