应用LIBS技术检测食盐中的镉

为了实现食盐中重金属镉(Cd)的快速定量检测,以193nm的自制准分子激光器作为激发光源,通过外部添加重金属元素Cd制作了8组食盐样品,采用激光诱导击穿光谱(LIBS)技术,选取CdⅠ228.8nm特征谱线作为分析线,进行了理论分析和实验验证。结果表明,延迟时间为1.5μs时,能够获得较好的光谱强度和信背比;谱线强度与Cd的质量分数具有很好的线性关系,拟合度为0.984,预测相对误差小于7%,检测限为0.65mg/kg。LIBS检测技术不仅具有快捷方便、无需繁琐样品准备等优点,而且具有较高的检测精度,是一种在食品安全快速检测领域中非常新颖的、有潜力的检测技术。

Detection of Cd in table salt by LIBS technology

In order to realize the rapid quantitative detection of heavy metal cadmium (Cd) in table salt, 8 groups of salt samples were made by adding heavy metal element Cd and the self-made 193nm excimer laser was used as excitation source. By choosing Cd Ⅰ 228.8nm characteristic spectrum line as analysis line, laser induced breakdown spectroscopy (LIBS) technology was used in theoretical analysis and experimental verification. The experiment results show that, when the delay time is 1.5μs, the better spectral intensity and signal-to-background ratio can be obtained. The spectral line strength has a good linear relationship with mass fraction of Cd. The fitting degree is 0.984, the predicted relative error is less than 7%, and the detection limit is 0.65mg/kg. LIBS detection technology not only has the fast and convenient advantages without the need of tedious sample preparation, but also has high detection precision. It is a very novel and potential detection technology in the field of rapid detection of food safety.