【摘要】 称取食品样品5.000 0g置于50mL容量瓶中,加入1.0g·L^-1丁酸标准溶液1mL作为内标,加水约25mL,涡旋混匀,超声提取30min,使双乙酸钠和丙酸钙从样品溶出进入溶液中,加水至刻度,摇匀,过滤,分取滤液5mL置于顶空瓶中,加入硫酸-甲醇（15+85）混合液2mL,盖紧瓶盖,在85℃进行衍生反应30min。然后在进样量为1mL的条件下,用DB-624色谱柱作为分离柱,在70～240℃区间按程序升温条件进行色谱分离,并用氢火焰离子化检测器（FID）进行检测。双乙酸钠和丙酸钙（以丙酸计）的线性范围均在200mg·L^-1以内。另测得上述2种化合物（丙酸钙以丙酸计）的检出限（3S/N）均为0.01g·kg^-1。取3种食品作为基质,加入分析物的标准溶液进行回收试验,测得回收率在95.1%～105%之间,测定值的相对标准偏差（n=6）≤5.0%。对3种食品样品各加相同量(0.50g·kg^-1)的两种待测物标准溶液后,分别按试验方法和国家标准方法进行测定,所得2种方法的测定结果之间无显著差异。更多还原

【Abstract】 5.000 0 g of food sample were placed into a 50 mL volumetric,and 1 mL of 1.0 g·L^-1 butyric acid standard solution was added as internal standard.About 25 mL of water were added and the mixture was mixed vortically and extracted ultrasonically for 30 min to have the diacetate and propionate dissolved in water.After diluting to mark with water and mixing thoroughly,the mixture was filtered and 5 mL of the filtrate were transferred to the head-space flask.2 mL of the mixture of H₂SO₄ and methanol（15+85）were added and the HSflask was closed tightly with its cap.Derivatization was taken place in the HS-flask at 85℃for 30 min.An aliquot of 1 mL of the solution in HS-flask was introduced into and separated on the DB-624 chromatographic column under the programed temperature elevation condition in the interval from 70 ℃to 240 ℃.The analytes were determined by the H₂-FID.Linearity ranges of sodium diacetate and calcium propionate（expressed as propionic acid）were obtained in the same range within 200 mg·L^-1.And values of detection limits（3 S/N）found for sodium diacetate and calcium propronate（expressed as propionic acid）were same as 0.01 g·kg^-1.3 kinds of blank food samples were taken as matrixes,and tests for recovery and precision were made by standard addition method with 6 parallel determinations,giving values of recovery in the range of 95.1%to 105%,and values of RSDs（n=6）≤5.0%.On the base of the 3 food samples,same amounts(0.50 g·kg^-1)of standard solutions of the 2 analytes were added,and the synthetic samples were analyzed by the present method and the method given in GB standards,giving results with good conformity and without significant deviation.更多还原