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目的证实铁氰化钾在原子荧光光谱法测定硒时的作用,以及确定加入铁氰化钾后最佳放置时间。方法取4份不同的食品样品湿法消化后,平行分成两组,上机前将其中一组加铁氰化钾,分别进行精密度测定;取食品样液和人工配制饮用水样各一份作本底,测定在加与不加铁氰化钾两种情况下的加标回收率;对1份食品样液加入铁氰化钾后的荧光值每隔20 min测定一次。结果 4份食品样液在加铁氰化钾时测定值分别为27.04、9.42、13.17、23.02μg/L,RSD分别为0.9%、4.1%、2.7%、1.4%;不加铁氰化钾时测定值分别为26.54、8.60、12.26、22.39μg/L,RSD分别为1.5%、3.6%、3.1%、1.3%。经t检验,t_1=3.030,t_2=3.268,t_3=3.473,t_4=5.811,均大于df=5时t_(0.05)(2.571),P<0.05,所以4个样液在两种情况下的测定结果差异有统计学意义。食品样液、饮用水样的加标回收率在加铁氰化钾时分别为96.4%~101.6%、97.3%~102.2%,不加铁氰化钾时分别为87.1%~92.3%、97.4%~101.2%。食品样液两种情况下回收率经t检验,t=5.329,大于df=3时t_(0.05)(3.182),所以食品样液两种情况下回收率差异有统计学意义;水样两种情况下回收率经t检验,t=0.395,小于df=3时t_(0.05)(3.182),所以水样两种情况下回收率差异无统计学意义。结论铁氰化钾在食品中硒的测定中起着重要作用。加入铁氰化钾后无需放置,混匀即可测定。
Objective To confirm the role of potassium ferricyanide in the determination of selenium by atomic fluorescence spectrometry and to determine the optimal placement time after addition of potassium ferricyanide. Methods Four different food samples were wet digested and divided into two groups in parallel. One group was added with potassium ferricyanide before the machine, respectively, for the determination of the precision. Take a sample of food samples and a sample of artificial drinking water As the background, with or without added potassium ferricyanide to determine the two cases of spike recovery; the fluorescence value of a sample of food solution after adding potassium ferricyanide measured every 20 min. Results The results of four food samples were 27.04, 9.42, 13.17 and 23.02 μg / L respectively with RSD of 0.9%, 4.1%, 2.7% and 1.4%, respectively. No potassium ferricyanide The measured values were 26.54,8.60,12.26,22.39μg / L, RSD were 1.5%, 3.6%, 3.1%, 1.3%. The results of t test showed that t_1 = 3.030, t_2 = 3.268, t_3 = 3.473, t_4 = 5.811, all of which were greater than t_ (0.05) (2.571), P <0.05 at df = 5 The difference was statistically significant. The spiked recoveries of food samples and drinking water samples were 96.4% ~ 101.6% and 97.3% ~ 102.2%, respectively, while those without potassium ferricyanide were 87.1% ~ 92.3% and 97.4%, respectively. ~ 101.2%. The recovery rate of food sample solution under two conditions was t-test, t = 5.329, t 0.05 (3.182) when df = 3, so there was significant difference in recoveries between the two samples In the case, the recovery rate was t-test, t = 0.395, less than t_ (0.05) (3.182) when df = 3, so there was no significant difference in recoveries between the two water samples. Conclusion Potassium ferricyanide plays an important role in the determination of selenium in foods. After adding potassium ferricyanide without placing, mixing can be measured.