キャピラリー電気泳動による牛乳中の乳酸及び酢酸の同時定量

抄録

A simple and rapid method by capillary electrophoresis (CE) was developed for the simultaneous determination of lactic acid and acetic acid in milk. The milk was diluted with water and deproteinized by an ultrafiltration filter (5,000 Da cut-off). Filtrate was analyzed by CE. The detection limits and the lenearity were 10mg/L, 10 〜 1,000mg/L of lactic acid and 5mg/L, 5 〜 1,000mg/L of acetic acid. Mean recoveries of lactic acid and acetic acid added to milk samples were 96.3% and 98.1%, and relative standard deviation of repeatability (RSD) was within 1.51% and 1.94% at level of 1mg/g. Total concentration of lactic acid and acetic acid was correlated with acidity in milk. (r=0.9916) The determination of lactic acid and acetic acid by this method is a useful way to judge lost freshness of milk easily and rapidly.