紫外分光光度法和FAAS法测定青稞中九种矿质元素含量

采用紫外分光光度-硫酸钡比浊法和干灰化-火焰原子吸收分光光度法对5个品系青稞中的S，Zn，Ca，Mg，K，Na，Fe，Cu，Mn 9种矿质元素含量进行了测定，并对方法的精密度、准确度、稳定性和重复性进行了分析。结果显示各元素检测方法的精密度在1.2%～3.7%之间，加标回收率在97.44%～101.52%之间，准确度在1.3%～3.8%之间，说明该方法具有较高的精密度和准确度;各元素检测方法的重复性在2.6%～6.1%之间，且样品溶液在室温下放置24 h后各元素含量基本不变，说明该方法具有较好的重复性和稳定性。在所有青稞样品中，各元素平均含量依次为K＞S＞Mg＞Ca＞Fe＞Na＞Zn＞Mn＞Cu，且与人体健康密切相关的Zn, Fe, Mn元素的含量均相对较高。其测定结果可为青稞的进一步开发利用提供科学依据。

Determination of Nine Mineral Elements in Hulless Barley by Ultraviolet Spectrophotometry and Flame Atomic Absorption Spectrometry

The contents of nine mineral elements, including sulphur, zinc, calcium, magnesium, potassium, sodium, iron, cop-per and manganese in five hulless barley (Hordeum vulgate L. var. nudum Hook. f.) lines were determined by ultraviolet spectrophotometry and flames atomic absorption spectrometry (FAAS). For the determination of sulphur, the samples were dis-solved by magnesia and anhydrous sodium carbonate at 250 ℃ for 0. 5 h and at 550 "C for 3 h in the muffle furnace, and then a certain amount of barium chloride was put into the sample solution for colorimetry of the UV-Vs spectrophotometer. For the de-termination of other eight mineral elements, all of the samples were dissolved by a kind of incinerating method, first, the sample was put into the muffle furnace at 250 ℃ for 0. 5 h and at 550 ℃ for 2. 5 h, then two droplets of 50%HNO_3 were distributed in-to each sample, and the last step was putting the sample into the muffle furnace at 550 ℃ for 0. 5 h. And then all of the ash was dissolved by 50%HNO_3to 50 milliliter and determined by flames atomic absorption spectrometry. The precision, accuracy, re-peatability and stability of the method were discussed too. The results showed that the relative standard deviations (RSD) were between 1.2% and 3.7%; The average recoveries were 97. 44%-101. 52% and the relative standard deviations (RSD) of sample determination were 1.3%-3.8%. The repeatability experiment showed that the relative standard deviations (RSD) were 2.6%-6.1%. And the content of each mineral element was the same after 24 hours; All these showed that the method has a good preci-sion, accuracy, repeatability and stability. In all the hulless barley samples, the average contents were in the order of K>S>Mg >Ca>Fe>Na>Zn>Mn>Cu, and the contents of zinc, iron and manganese closely related to people's health were relatively higher than other crops. The data of the experiment could provide an accurate and credible evidence for the deeper exploitation of the hulless barley.