[Elementary Analysis of Seashell Based on Calcium Internal Reference with Micro-Probe Laser Induced Breakdown Spectroscopy (Micro-LIBS)].

The shellfish has been extensively applied as a proxy for marine ecosystem monitoring, and the climate evolution or the shell growth might be derived from the elementary spatial distribution when using calcium (Ca) as the internal reference. Differed from other technique, the calcium emission lines are spread all over the wavelength range when applying Micro-probe Laser Induced Breakdown Spectroscopy (Micro-LIBS) to analyze the shell. So it is crucial to select a suitable calcium line for the shell elementary analysis. In this paper, the scallop shell composition was analyzed by comparing calcium internal references of total-line, atomic line (Ca Ⅰ 422.7 nm/Ca Ⅰ 487.9 nm) and ionic line (Ca Ⅱ 393.3 nm). It was found that, the fluctuation of Sr/Ca ratio was less than 7% and 10% in the investigated area when using total-line and strongest atomic line (Ca Ⅰ 422.7 nm) as the reference respectively, which was in agreement with the shell growth development. What's more, the obtained results indicated that the element ratio Li/Ca had a high correlation to K/Ca and Na/Ca rather than Mn/Ca, so the light elements might be accumulated in a same pattern during the shell growth development. It was suggested that Micro-LIBS was a practical way for the seashell investigation, and a better elementary analysis could be achieved by using the internal reference of calcium total-line or the strong atomic line, while not in case of calcium ionic line.

[Study of Ultrasonic Nebulizer Assisted Spark Induced Breakdown Spectroscopy as a Metal Elements Analysis Method for Aqueous Sample].

In order to develop a high sensitive and low cost metal elements analysis method for aqueous sample, an ultrasonic nebulizer assisted spark induced breakdown spectroscopy (UN-SIBS) system is established, where an ultrasonic nebulizer is employed to transform the bulk liquid sample into aerosol composed by intensive droplets. And a high tension coil and a couple of electrodes are combined to induce the plasma. The spectra emitted are collected to analysis the metal elements in the aqueous samples. Based on the experimental system, the features of emission spectra are studied. The electron density and electron temperature are calculated to understand the physics characteristic of the plasma in UN-SIBS experiments. Samples of different concentration of lead are analyzed by UN-SIBS method to make clear of the relationship between concentration and the peak intensity of the heavy metal element Pb. Besides, the atomic line of lead at 261.37 nm detected by the sample with the concentration of 2.07 ppt could be easily distinguished which is better than the LOD reported in references. The aqueous samples with calcium, as a lower activity metal element, are also studied. At last, the possible mechanism is discussed according to the experimental results.