[Simultaneous determination of total flavone and total saponin in Gynostemma pentaphyllum by signal multiplier spectrophotometry].

Important chemical constituents analysis for the total flavone and total saponin in Gynostemma pentaphyllum is described. The colour reactions of flavones and saponines with vanillin-perchloric acid in acetic acid produced the good absorptions at 451 and 547 nm, but the absorption peaks too overlapped to be determined simultaneously. A new method for the total flavone and the total saponin in Gynostemma pentaphyllum to be determined by signal multiplier spectrophotometry simultaneously without any preliminary separation was proposed. For quantitative analysis, the rutinum as a standard of the total flavone and the ginsenoside Rb1 as standard of the total saponin were applied. The experiment results showed that the regression equations of concentration and deltaA were obtained: deltaAflavone = 0.0133+4.417 0Cflavone, relation coefficient rflavone = 0.9994, and the total flavone concentrations were in 0-0. 16 microg x mI(-1) with deltaA obeying linear relation; deltaAsaporin = 2.775 5Csaponin -0.8881 x 10(-2), relation coefficient rsaponin = 0.9991, and the total saponin concentrations were in 0-0.30 microg x mL(-1) with deltaA obeying linear relation respectively. The recovery ratio was 104.0%-113.0% and 86.8%-94.6% respectively. The RSDflavone was less than 0.58% (n = 9) and RSDsaponin was less than 0. 35% (n=9) respectively. The proposed method is simple, rapid accurate and feasible.

[Quantitative determination of total flavonoids in sea-buckthorn fruit juice by three wavelength spectrophotometry].

Numerous studies dealing with the quantitative determination of total flavonoids in sea-buckthorn fruit juice by spectrophotometry are presented. The flavonoids in sea-buckthorn fruit juice and aluminate produce stable complex whose absorption occurred at longer wavelength. To determine the total flavonoids in sea-buckthorn fruit juice by traditional spectrophotometry method, baseline shift and asymmetric absorption peak occurred on the absorption curve. Quantitative determination of flavonoids in sea-buckthorn fruit juice by three wavelength spectrophotometry method can eliminate the absorbance error caused interfering components in turbid solution and the scattering effect. Background changing with the concentration change and asymmetric absorption peak problems can also be solved. The regression equation of concentration vs deltaA was obtained: deltaA = - 0.00703 + 0.00048c with a relation coefficient gamma = 0.9991. The experimental results demostrate the total flavonoids concentrations in 0-800 microg x mL(-1) with deltaA obeying linear relation when the absorbance was measured at wavelength lambda1 = 495 nm, lambda2 = 415 nm and lambda3 = 368 nm. The recovery is 97.0%-101.0% and the coefficient of variation is 0.058% (n = 9). The method is more advantageous than tranditional spectrophotometry method.

[Determination of catechin by three wavelength spectrophotometry and the antioxidation effect in natural teas and their beverages].

OBJECTIVE: To determine the catechin and the antioxidation effect in natural tea and their beverages. METHODS: Three wavelength spectrophotometry can eliminate the absorbance error of interfering components, turbid solution and the scattering effect. Background changedwith concentration changed and asymmetric absorption peak problems can be solved, and the antioxidation effect of natural tea and their beverages was studied by the flow-injection chemiluminescence. RESULTS: The recovery is 95.2%-102.0% and the coefficient of variation is 1.05%. Conclusion The results have shown that natural tea and their beverages are abundant in the catechin compounds and strong antioxidative effect.

[Determination of germanium in A. arborescens by spectrophotometric method].

A new spectrophotometric method for the determination of germanium in A. arborescens was developed. The method was based on the fact that germanium forms a stable complex with phenylfluorone in the acidified solution with CTMAB as solubilization agent. The maximum absorption of association complex is at 530 nm, the linear range is 0.1-0.7 microg x mL(-1), the regression equation is A = 0.0817 + 0.8677c530, (microg x mL(-1)) the correlation coefficient r=0.9177, and the limit of detection is 0.65 microg x mL(-1). The leaves and stems of A. arborescens were determined by the proposed method. The total amount of germanium is 697.0-1219.5 ng x g(-1), and the content of organic Ge is 95.45%-98.99%. The method is suitable for the analysis of samples which contain both organic Ge and inorganic Ge.