Determination of Five Plant Growth Regulator Containing Carboxyl in Bean Sprouts Based on Chemical Derivatization by GC-MS

Abstract

An efficient and sensitive analytical method for the simultaneous determination of five plant growth regulators (PGRs) has been successfully developed, including 3-Indoleacetic acid (IAA), 2-Naphthylacetic acid (2-NAA), Beta-indolebutyric acid (IBA), 2-(2,4-dichlorophenoxy), acetic acid (2.4-D), and 4-Chlorophenoxyacetic acid (4-CPA) in bean sprouts. Using 10% boron trifluoride of methanol as the derived reagent and the reaction was derivatized at 70 °C for 30 min, the derivatives of five PGRs have been completely separated within 19 min. It has a linear relationship in the concentration range of 0.01–0.20 mg/kg and the correlation coefficients (r2) in excess of 0.997. The average recoveries were ranged from 72.7–98.6% at three spiking different concentration levels of 0.05, 0.10, and 0.15 mg/kg, respectively. The relative standard deviations (RSDs) were ranged from 1.2 to 9.0%. The limits of detection and the limits of quantification were ranged from 0.00024 to 0.00172 mg/kg and 0.0008–0.0052 mg/kg, respectively. On the basis of these, the measurement has been successfully applied to the analysis of the exogenous phytohormones in the bean sprouts. Except for 4-CPA and IAA, the rest of the analytes were undetected in samples. In sum, the current method can be used for accurate determination and confirmation of PGRs in many other crops, such as bean sprouts.