A quantitative analysis method by UV spectrophotometry monitoring biosynthesis was established with isoabsorptive point,being based on the UV spectral characteristics of trans-anethole and anisic acid and its mixture. Standard equation of absorbance at 250 nm and total molar concentration of mixture was A250.0 = 16.931Ct +0.012 8 ,and linear range at 0.01 ~0.06 mmol/L;while the total molar concentration was 0.04 mmol/L,standard equation of absorbance at 268.5 nm of mixture and molar fraction of trans-anethole was A268.5 =0.3427X +0.311 2. According to spectral simulation and A250.0 ,A'268.5,A'250.0 and A "268.5 before and after one sample dilution, A268.5 = (0.675 6 -A'250.0) (A'268.5 -A "268.5)/(A250.0 ~ A'250.0) +A "268.5 while the sample total molar concentration at 0. 04 mmol/L. The average recovery of trans-anethole and anisic acid was 98.40% and 96.47% respectively,and the relative standard deviation of them was 0.68% ,0. 80% . Comparing with HPLC, the t value test was less than the critical value of 1.724 7 (a = 0.05). The results showed that the method was accurate and reliable,and had no significant difference with HPLC, which provided reference for monitoring biosynthesis process by UV spectrophotometry.%根据反式茴脑和茴香酸及其混合物的紫外光谱特性,利用等吸收点建立了一种监测生物合成过程的紫外定量分析方法.混合物在250.0 nm处的吸光度与其总摩尔浓度的标准曲线A250.0=16.931Ct+0.012 8,线性范围为0.01 ～0.06 mmol/L;当总摩尔浓度为0.04 mmol/L时,混合物在268.5 nm处的吸光度与反式茴脑的摩尔分数的标准曲线为A268.5=0.342 7X +0.311 2.据某样品稀释前后的A250.0、A'268.5、A′250.0和A"268.5及光谱模拟得到该样品浓度为0.04 mmoL/L的A268.5=(0.675 6-A'250.0)(A'268.5-A"268.5)/(A250.0-A'250.0)+A"268.5.反式茴脑和茴香酸的平均回收率分别为98.40％和96.47％,相对标准偏差分别为0.68％和0.80％,与高效液相色谱法比较的t值均小于结果的临界值1.724 7(α =0.05),表明该方法与高效液相色谱法无显著性差异,准确可靠,可为紫外分光光度法监测生物合成过程提供参考.
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