GC Determination of Phthalates in Exudation from Root of Hot Pepper with Head-Space SPME

GC with head-space SPME was applied to the determination of 5 phthalates in exudation from root of hot pepper. Ten mL of the sample, i.e., the nutritious liquor in which hot pepper seedlings were cultivated hydroponically, were transferred into the head space flask, and SPME was carried out with 65 μm PDMS/DVB fibre head as microextractor and under the following conditions: ① time and temperature of extraction: 50 min, 80 ℃; ② rate of agitation: 1 000 r·min-1; ③ ionic strength of sample solution: content of NaCl amounted to 18%; ④ acidity of sample solution: nearly neutral; the initial acidity of the sample (pH 6.5-7.2) conformed with this requirement; ⑤ temperature and time of desorption: 250 ℃, 10 min. At the end of SPME, the microextractor was inserted quickly into the sample inlet of chromatograph, and desorbed. As shown by the results, linearity ranges of the 5 phthalates were found to be same between 0.2 and 10 mg·L-1, with detection limits (3S/N) all less than 0.12 mg·L-1. Values of recovery of the method were found between 83.4% and 105% and values of RSD′s (n=5) were all less than 9%.