电感耦合等离子体原子发射光谱法测定钒铁中8个杂质元素含量和方法精密度的验证

提出了电感耦合等离子体原子发射光谱法(ICP-AES)测定钒铁中硅、磷、铝、锰、镍、铬、铜、钛共8个杂质元素含量的方法。钒铁样品(0.5000g),先后加入50%(体积分数)硝酸溶液20mL及50%(体积分数)盐酸溶液10mL,在100℃左右加热溶解,溶解过程中应注意保持溶液体积在25mL左右。将溶液过滤并置于200mL容量瓶中作为母液留用。将滤纸及不溶物一并移入铂坩埚中,置于马弗炉中,先于250℃灰化20min,稍冷后加入无水碳酸钠和硼酸(质量比2∶1)组成的混合熔剂0.3g,升温至950℃融熔15min。冷却,用体积比1∶10的盐酸溶液10mL浸出熔块,将此溶液与上述母液合并并加水定容至200mL。此溶液供ICP-AES在仪器工作条件下进行分析。绘制校准曲线时,加入纯铁和五氧化二钒作为基体,以消除基体干扰,然后加入上述8种元素的标准溶液,并按上述溶液最终稀释体积条件和仪器工作条件制作曲线(R大于0.999)。为验证所提出的分析方法的测定数据的精密度,约请了10个实验室对8个不同含量水平的钒铁样品对方法作协同试验,按GB/T 6379.2-2004所规定的方法求算了重复性标准偏差Sr和重复性限r,以及再现性标准偏差SR和再现性限R,并求得所测定的8种元素在各自的测定范围内的r与w之间和R与w之间的函数关系,说明该方法有较好的稳定性和准确性,而且证明此方法是可行的。

ICP-AES Determination of 8 Elements in Ferrovanadium and Verification of Precision of the Method

An ICP-AES method for determination of 8elements(i.e,.silicon,phosphorus,aluminum,nickel,chromium,copper and titanium)in ferrovanadium was proposed and precision of the method was verifed.The sample(0.5000g)was dissolved by heating with 20mL of 50%(volume fraction)nitric acid solution first and then with 10mL of 50%(volum fraction)hydrochloric acid solution during the course of which water was added intermittently into the solution to keep its volume around 25mL.The solution was filtered into a 200mL volumetric flask,and the filtrate was kept as mother solution for further use.The filter paper with its insolubles was transferred into a Pt-crucible and ashed in a muffle furnace at 250℃for 20min,and then fused with 0.3g of a mixed flux containing anhydrous sodium carbonate and boric acid and boric acid(mixed in the mass ratio of 2∶1)at 950℃for 15min.After cooling,the melt was taken up with 10mL of hydrochloric acid solution with a volume ratio of 1∶10.The solution obtained was combined with the mother solution in the 200mL volumetric flask,and water was added to the mark.This solution was used as testing solution for ICP-AES analysis under the working condition of the instrument.Calibration curves(R>0.999)for the 8elements were prepared with the standard solution and matrix matching method was used to overcome the matrix effect.Verification of precision of the method proposed was carried out according to the national standard of GB/T 6379.2-2004.Interlaboratory study was conducted among 10laboratories by analyzing a set of 8ferrovanadium samples with contents of the 8elements in 6 gradient concentration levels.Values of repeatability standard deviation Srand repeatability limit r,as well as the reproducibility standard deviations SR and reproducibility limit R were calculated.And the functional relationships between r and w(mass fraction of the element),and between Rand wfor the 8elements in various concentration ranges were finally determined,showing that satisfactory precision and accuracy were attained by the method,and that feasibility of the method was proved.