摘要
运用酪氨酸与４－氨基安替吡啉的显色反应测定食品中酪氨酸的含量。微波加热水解３０ｓ后，可在不分离其它氨基酸的条件下直接测定酪氨酸。向５ｍＬ的水解液中依次加入５ｍＬ５．０×１０－２ｍｏｌ／Ｌ４－氨基安替比林，２．５ｍＬＮＨ４ＯＨ－ＮＨ４Ｃｌ缓冲溶液（ｐＨ９．４０），２．５ｍＬ０．１ｍｏｌ／Ｌ高碘酸钠溶液，用二次水定容于５０ｍＬ。显色２５ｍｉｎ后，以空白作参比，在４８０ｎｍ波长下测定吸光度值。浓度在６．０×１０－６～１．８×１０－４ｍｏｌ／Ｌ的酪氨酸符合比耳定律。表观摩尔吸光系数为３．０３×１０３Ｌ／ｍｏｌ．ｃｍ。对含量为３．１９％酪氨酸样品多次重复测量，相对标准偏差为０．４２％。考察了其它氨基酸对测定的干扰。该方法测定的回收率为１００．４％～１０２．０％。同时推测了显色反应的机理。
new method which used the color reaction of tyrosine with 4 aminoantipyrine to determine the content of tyrosine in food was developed.Heated in a microwave oven for 30s,the protein in food was completely hydrolyzed Without separation ,tyrosine could be determined directly.Sequentially 5mL of 5.0×10 -2 mol/L 4 aminoantipyrine,2.5mL of ammonia buffer solution (pH 9.40) and 2.5mL of 0.1mol/L sodium periodate were added to 5mL of the hydrolytic solution,and diluted to 50mL with distilled water.After 25 minutes the absorbance was measured at 480nm. Beer's law was obeyed for tyrosine in the range of 6.0×10 -6 ～1 8×10 -4 mol/L The apparent molar absorptivity was 3.03×10 3 L/mol·cm A relative standard deviation of 0.42% for replicate measurements of 3.19% tyrosine was obtained.Interferences from other amino acids were examined.The developed method was applied to tyrosine determination in various food samples,the recovery range was from 100.4% to 102.0%.The mechanism of the color reaction has been deduced too.
出处
《分析试验室》
CAS
CSCD
1998年第4期61-63,共3页
Chinese Journal of Analysis Laboratory
