利用激光诱导离解光谱检测铍铝元素区分透闪石白玉产地

利用自行搭建的激光诱导离解光谱仪分析54块新疆、青海、俄罗斯产地的透闪石白玉样品,提出通过检测Be、Al元素来区分白玉产地的方法。使用波长1064 nm的激光器激发样品,4CCD光谱仪采集光谱,为避免外界条件干扰,以透闪石白玉中含量比较固定的Si元素作为内标元素测量原子谱线强度比值IBe/ISi、IAl/ISi,分别代表Be、Al元素的含量变化,重复测量10次的相对标准偏差(RSD)<3%。结果表明,新疆白玉的IBe/ISi为0.3～0.6,IAl/ISi为0.1～0.4;青海白玉IBe/ISi<0.1,IAl/ISi<0.2,显示出低Be低Al的明显特征;俄罗斯白玉的IBe/ISi分为高值和低值两个区域,部分样品的IBe/ISi>0.7,指示Be的含量较高,另一部分样品的IBe/ISi为0.1～0.5,略低于新疆白玉。研究显示Be、Al元素特别是Be元素具有较好的产地指示意义,激光诱导离解光谱技术用于鉴别白玉产地有着较好的推广前景。

Determination of Be and Al for Source Region Identification of White Nephrite Using Laser-Induced Breakdown Spectroscopy

A method to identify the source region of white nephrite by detecting element Be and Al with laser-induced breakdown spectroscopy is proposed to measure chemical compositions of 54 white nephrite samples collected from Xinjiang, Qinghai, and Russia. A laser excitation wavelength of 1064 nm was used and the spectrum was collected by a spectrometer with 4CCD. Multiple measurements were taken for each sample in order to meet the relative standard deviation (RSD) <3%. Elemental Si was applied as the internal standard, because the content of Si in white nephrite is almost invariable. By doing this, the intensity ratios of I_Be/I_Si and I_Al/I_Si can directly represent the contents of element Be and Al in samples. The results indicate that the I_Be/I_Si ratios of Xinjiang samples are high, ranging from 0.3 to 0.6, with I_Al/I_Si ratios of 0.1 to 0.4. The Qinghai samples had the most obvious features of very low Be and Al, such as the I_Be/I_Si ratios being lower than 0.1 and I_Al/I_Si ratios lower than 0.2. The Russian samples had two different distribution areas. I_Be/I_Si ratios of some samples were higher than 0.7, indicating high levels of Be. However, some I_Al/I_Si ratios were between 0.1 and 0.5, which were slightly lower than the Xinjiang samples with a little overlap. The experimental results show that elemental Be and Al, especially elemental Be have an obvious origin character The laser-induced breakdown spectroscopy had a good application value for nephrite source region identification.