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首页> 外文期刊>X-Ray Spectrometry: An International Journal >Determination of trace elements in aqueous solutions using the EMMA miniprobe XRF analyzer
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Determination of trace elements in aqueous solutions using the EMMA miniprobe XRF analyzer

机译：使用EMMA miniprobe XRF分析仪测定水溶液中的痕量元素

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摘要

The energy-dispersive miniprobe multielement analyzer (EMMA) is an XRF instrument to measure trace elements (As, Cr, Cu, Fe, Ga, Ge, Hf, Mn, Ni, Pb, Rb, Se, Sr, Th, Y, U, Zn) in small samples (down to ca 10 mu m). Originally designed and constructed for analyzing individual mineral grains fromks, EMMA can also be used for analyzing small volumes of aqueous solutions such as natural waters and acid digests. Liquid samples (100-150 mu l) are evaporated on to a thin (4 mu m) Teflon film in increments of 10 mu l by heating with a lamp. This process leaves a circular residue which is then excited using a monochromatic x-ray beam (0.1 x 2.5 mm). Because monochromatic x-radiation is used for excitation (17.44 keV, Mo K alpha ), a low background is achieved and detection limits are excellent, ranging from 20 pg Sr to 700 pg Pb (ca 0.02-0.7 ng ml exp -1 ) for 100 mu l of dilute natural water. Using an internal Y standard to quantify elemental concentrations, analyses of NIST SRM 1643C Trace Elements in Water were in good agreement with the certified values. With respect to acid digests of modern plant material, compared with solid samples the digests are characterized by a significantly lower background and improved detection limits. For example, Pb in a solid sample of NIST SRM 1515 Apple Leaves (0.47 mu g g exp - 1 ) was below the limit of detection using EMMA (0.6 mu g g exp -1 ). However, Pb could easily be quantified in the acid digest of the same material, and was in excellent agreement (0.46 mu g g exp -1 ) with the certified value. Similarly, acid digestion allowed the quantitation of Se in peat samples from continental bogs and As, Se and Pb in peat samples from maritime bogs. The main advantages of this method are the small volumes of solution required, the multielement capability [from Z = 19 (K) to Z = 92 (U)], sensitivity and low cost of analysis per sample. Unlike total reflection XRF (TXRF) methods, the detection limits which can be achieved using the EMMA technique are less dependent on the concentration of the matrix, making it useful for solutions ranging in ionic strength from rainwater to acid digests of biological and geological solid samples.
机译：能量分散型微型探针多元素分析仪（EMMA）是XRF仪器，用于测量痕量元素（As，Cr，Cu，Fe，Ga，Ge，Hf，Mn，Ni，Pb，Rb，Se，Sr，Th，Y，U ，锌）的小样品（低至约10微米）。 EMMA最初设计和构造用于分析来自矿物的单个矿物颗粒，也可用于分析少量水溶液，例如天然水和酸消化液。通过用灯加热，将液体样品（100-150μl）蒸发成10μl增量的特氟龙薄膜（4μm）。该过程留下了圆形残留物，然后使用单色X射线束（0.1 x 2.5 mm）对其进行激发。由于使用单色x射线进行激发（17.44 keV，Mo K alpha），因此背景本底较低，检测极限极佳，其检测范围为20 pg Sr至700 pg Pb（约0.02-0.7 ng ml exp -1）。 100升稀自然水。使用内部Y标样定量元素浓度，NIST SRM 1643C水中痕量元素的分析与认证值高度吻合。关于现代植物材料的酸消解物，与固体样品相比，消解物的特征是背景显着降低且检测限提高。例如，NIST SRM 1515苹果叶片固体样品中的铅（0.47 g g exp-1）低于使用EMMA的检测极限（0.6 g g g -1）。但是，Pb可以很容易地在相同物质的酸消解物中定量，并且与认证值极佳地一致（0.46μgg exp -1）。同样，酸消解法可定量分析大陆沼泽泥炭样品中的硒，以及海上沼泽泥炭样品中的As，Se和Pb。该方法的主要优点是所需溶液体积小，多元素分析能力[从Z = 19（K）到Z = 92（U）]，灵敏度高且每个样品的分析成本低。与全反射XRF（TXRF）方法不同，使用EMMA技术可以达到的检测极限对基质浓度的依赖性较小，这使其适用于离子强度范围从雨水到生物和地质固体样品的酸消化物的溶液。

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