Cheburkin A K, Shotyk W
Geological Institute, Ukrainian Academy of Sciences, Chkalova St. 55-b, Kiev, Ukraine.
Anal Bioanal Chem. 1996 Mar;354(5-6):688-91. doi: 10.1007/s0021663540688.
An Energy-dispersive Miniprobe Multielement Analyzer (EMMA) was designed and constructed for sensitive, rapid, and non-destructive analysis of trace elements (As, Cr, Cu, Fe, Ga, Ge, Hf, Mn, Ni, Pb, Rb, Se, Sr, Th, Y, U, Zn) in small (e.g. 50 microm) samples such as individual mineral grains from rocks. An alternative configuration of the EMMA instrument is described here for use with larger samples such as powders of coal, soil, sediments, and plant materials. To minimize heterogeneity problems, a larger X-ray beam size (0.1 x 6 mm) was used by installing a different collimator, and the sample holder rotated 25 times per minute. Using this approach, Rb, Sr, Cu, Zn and Pb were measured in peat samples collected from bogs in Switzerland and northern Scotland. The detection limit for Pb, for example, is approximately 0.3 microg/g which is one order of magnitude better than conventional XRF analyzers. For comparison, Pb was also measured in acid digests of the same samples using GFAAS. The Pb results obtained using EMMA are comparable to the GFAAS data for the continental peat samples. However, in the Cl-rich samples from the maritime bogs, the GFAAS signal was strongly suppressed, and an accurate comparison of the two methods was not possible. The EMMA technique, therefore, has three advantages over conventional GFAAS: first, no sample dissolution is required; second, several elements of interest are determined simultaneously; and third, the EMMA technique is not subject to matrix interferences.
设计并制造了一种能量色散微型探针多元素分析仪（EMMA），用于对小样本（如岩石中的单个矿物颗粒，例如50微米）中的微量元素（砷、铬、铜、铁、镓、锗、铪、锰、镍、铅、铷、硒、锶、钍、钇、铀、锌）进行灵敏、快速且无损的分析。本文描述了EMMA仪器的另一种配置，用于分析更大的样本，如煤、土壤、沉积物和植物材料的粉末。为了尽量减少不均匀性问题，通过安装不同准直器使用了更大的X射线束尺寸（0.1×6毫米），并且样品架每分钟旋转25次。采用这种方法，对从瑞士和苏格兰北部沼泽地采集的泥炭样本中的铷、锶、铜、锌和铅进行了测量。例如，铅的检测限约为0.3微克/克，比传统X射线荧光分析仪好一个数量级。为作比较，还使用石墨炉原子吸收光谱法（GFAAS）对相同样本的酸消解液中的铅进行了测量。使用EMMA获得的铅结果与大陆泥炭样本的GFAAS数据相当。然而，在来自海洋沼泽地的富含氯的样本中，GFAAS信号受到强烈抑制（无法准确比较两种方法）。因此，EMMA技术相对于传统GFAAS具有三个优点：第一，无需样品溶解；第二，可同时测定几种感兴趣的元素；第三，EMMA技术不受基体干扰。
