HPLC法同时测定4种焙炒咖啡豆中6种有机酸方法初探

A Primary Research on Simultaneous Determination of Six Organic Acids in Four Kinds of Roasted Coffee Beans by HPLC

建立了焙炒咖啡豆中同时测定柠檬酸、苹果酸、酒石酸、琥珀酸、没食子酸、富马酸的测定方法,以柠檬酸、苹果酸、酒石酸、琥珀酸、没食子酸、富马酸为对照品,对4种商品焙炒咖啡豆进行含量比较。从磨粉粒度、加粉量、水温、冲泡时间确定样品的提取条件,色谱柱:流动相:Acclaim^(TM)120 C_(18)(4.6 mm×250 nm,5μm),流动相:甲醇∶0.1%磷酸=25∶75,流速1 m L/min,柱温30℃,检测波长210 nm。结果表明:用常温的纯水提取5 g咖啡粉,咖啡粉用咖啡磨3档磨出,于40℃水温中超声5 min可以很好地提取出柠檬酸、苹果酸、酒石酸、琥珀酸、没食子酸、富马酸。酒石酸在2.5~30μg范围内具有良好的线性,R^2=0.9992;苹果酸在1.25~15.00μg范围内具有良好的线性,R^2=0.9997;柠檬酸在2~24μg范围内具有良好的线性,R^2=1.0000;琥珀酸在0.5~6.0μg范围内具有良好的线性,R2~=0.9999;没食子酸在0.025~0.300μg范围内具有良好的线性,R^2=1.0000;富马酸在0.025~0.300μg范围内具有良好的线性,R^2=1.0000,加标回收率分别为98.01%、100.29%、110.12%、96.55%、98.3%、106.32%。因此,该法具有快速、简洁、重现性好的特点,可用于检测咖啡豆中的有机酸。

A HPLC method for the simultaneous determination of citric acid, malic acid, tartaric acid, succinic acid, gallicacid and fumaric acid in roasted coffee beans was constructed, and the contents of these organic acids in 4 kinds of roasted coffeebeans were detected and compared by using this method. The extraction conditions for samples were confirmed from the aspects ofgrinding fineness, dosing weight, water temperature and brewing time. The HPLC conditions were ascertained as follows： Ac？claimTM120 C18 chromatographic column （4.6 mm×250 nm, 5 μm） ; mobile phase methyl alcohol plus 0.1% phosphoric acid （25∶75） ; flow rate 1 mL / min; column temperature 30 ℃; determination wavelength 210 nm. The results indicated that： under theconditions of extracting 5 g ground coffee from roasted coffee beans by using normal-temperature pure water, using 3-grade coffeegrinder to grind the ground coffee, and conducting ultrasonic dissolving for 5 min in 40 ℃ water, citric acid, malic acid, tartaricacid, succinic acid, gallic acid and fumaric acid could be extracted from roasted coffee beans very well. The linear correlation co？efficients （R2） of tartaric acid, malic acid, citric acid, succinic acid, gallic acid and fumaric acid were 0.9992, 0.9997, 1.0000, 0.9999, 1.0000 and 1.0000 respectively within the range of 2.5 ～ 30, 1.25 ～ 15.00, 2 ～ 24, 0.5 ～ 6.0, 0.025 ～ 0.300 and0.025 ～ 0.300 μg, and their standard-adding recoveries were 98.01%, 100.29%, 110.12%, 96.55%, 98.3% and 106.32%separately. Thus, this method was simple, convenient and quick with good reproducibility in use, and it could be used to detectthe organic acids in coffee beans.