为了增强电感耦合等离子体原子发射光谱强度, 改善对痕量重金属元素的检测水平, 本文采用波长为976 nm的近红外激光辐照水溶液, 研究了溶液表面张力和粘度的变化情况, 并且观测了处理后的水溶液对ICP光源的光谱强度和信背比的影响。 实验结果表明: 当激光辐照时间为60 min, 功率密度为0.3296W·cm-2时, 溶液的表面张力比未处理时的减小了36.73%, 粘度减小了9.73%。 将优化条件下激光辐照处理的水溶液引入到ICP光源中, 通过测量发射光谱强度可知, 样品元素Cd, Cr, Cu, Hg和Pb的谱线强度要比溶液未处理时的分别提高了73.52%, 22.97%, 33.86%, 24.44% 和 65.59 %, 光谱信背比分别增大了76.03%, 21.74%, 32.17%, 22.68% 和65.32%。 可见, ICP光源的光谱强度和信背比得到了明显改善, 为降低元素分析检出限奠定了基础。 另外, 经激光处理后的水溶液在30 min静置时间内其表面张力和粘度基本保持不变, 物理性质稳定。 这种简便易行的激光处理水溶液方法有助于提高ICP光谱法的检测能力。

To enhance the intensity of inductively coupled plasma-atomic emission spectrum and improve the detection level of trace heavy metal elements, the surface tension and viscosity of the aqueous solution processed by near-infrared laser at wavelength of 976 nm were studied in the present paper. The influences of the treated solution on the spectral line intensity and signal-to-background ratio of the ICP source were observed. The results showed that when the laser irradiation time was 60min and the power density was 0.329 6 W·cm-2, the surface tension and viscosity of the solution decreased by 36.73% and 9.73% respectively compared to the untreated solution. Under the optimum conditions, the aqueous solution treated by the laser irradiation was introduced into the ICP source. By measuring the intensity of emission spectrum of the sample elements, the spectral line intensity of Cd, Cr, Cu, Hg, and Pb was enhanced by about 73.52%, 22.97%, 33.86%, 24.44% and 65.59% compared to the untreated solution, while the signal-to-background ratio increased by 76.03%, 21.74%, 32.17%, 22.68% and 65.32%, respectively. Spectral line intensity and signal-to-background ratio of the ICP source were significantly improved so that the foundation was established for reducing the analysis detection limits. Further more, the surface tension and viscosity of the processed aqueous solution remain the same within 30 minutes standing time with the stable physical properties. This simple and easy method of laser-processed aqueous solution helps improve the detection capabilities of ICP spectrometry.