AIM To establish a flow injection chemiluminescence (CL) inhibition method for determination of tea polyphenols in green tea. METHODS The flow line of the sample, H 2O 2 and KIO 4 was inserted into luminol carrier solution. The mixed solution was led into the chemiluminescence cell for chemiluminescence reaction to occur and the CL intensity was recorded. RESULTS Tea polyphenols was shown to inhibit the CL reaction of luminol-H 2O 2-KIO 4 system in alkaline solution and the CL emission was inversely correlated with the tea polyphenols concentration. The linear range was 0.4～24.0 μg·mL -1 with a detection limit of 0.03 μg·mL -1 and a relative standard deviation of 1.3% (at tea polyphenols concentration 4.0 μg·mL -1, n=11). The sampling frequency was 240·h -1. CONCLUSION The method is simple, rapid and can be used for determination of tea polyphenols in green tea.
A kind of polythioether cellulose compound(PTEC)was synthesized by etherification of rice husk cellulose with chloromethylthiirane(CMT) in alkaline media. The preparation conditions have been investigated. The PTEC with 4 31% sulfur content was obtained by reacting 12 g rice husk cellulose with 36 mL chloromethylthiirane in 3 mol/L NaOH solution. The product has an adsorption capacity for Ag(Ⅰ) and Hg(Ⅱ) of 24 92 mg/g and 66 80 mg/g, respectively at pH=7 and for Pb(Ⅱ) it is 0 15 mg/g at pH=3. The fiber could be used as a adsorbent for metal ions.
