Determination of root exudative phenolic compounds in hot pepper (Capsicum annuum L.) by polydimethylsiloxane tube microextraction after derivatization
Polydimethylsiloxane (PDMS) tube microextraction for the determination of 2,3-dimethylphenol (2,3-DMP), 2,6-di-tert-butylphenol (2,6-DTBP) and 4,4′-(1-methylethyliden)bisphenol (4,4′-(1-M)BP) in root exudates of hot pepper (Capsicum annuum L.) by gas chromatography-mass spectrometry (GC-MS) was studied by optimizing derivatization and extraction conditions. Optimum extraction parameters were obtained including PFPy as derivative reagent; derivative reagent volume of 200 μL; sample solution pH of 11; extraction time of 30 min; extraction temperature of 60 °C; isooctane as elution reagent; elution reagent of 1.5 mL. The developed method shows good linearity levels in the range of 0.2–20 μg mL−1 with correlation coefficients of 0.9972, 0.9985 and 0.9978, and relative standard deviations in the range of 4.8–8.4% for 2,3-DMP, 2,6-DTBP and 4,4′-(1-M)BP, respectively, and it's extraction performance was better than that of SPE method. Recoveries ranging from 85.7 to 103.9% and the RSD below 7.9% were obtained when optimized method was applied to determine 2,3-DMP, 2,6-DTBP and 4,4′-(1-M)BP for 15 and 30 days' root hydroponic solution of hot pepper. The developed method is rapid, simple and inexpensive and offers high sensitivity, good reproducibility and satisfactory recovery.