Micro-hole array sprayer combined with an organic membrane to assist LIBS (MASOM-LIBS): A novel highly sensitive detection method for dissolved trace heavy metals in water

The development of highly sensitive and rapid detection technology for heavy metal elements in water is of great significance to the monitoring of water environmental pollution, sewage discharge control and other application fields. As an alternative detection method with great potential in the above fields, LIBS technology still has some problems that need to be solved. To improve the sensitivity and efficiency of LIBS detection of trace metals in water, a new method Micro-hole Array Sprayer combined with an Organic Membrane to assist LIBS (MASOM-LIBS) was proposed in this study. In this method, water samples were transformed into a large number of micrometer droplets by a micro-hole array injection device and were sprayed onto a rotating polypropylene organic film. After natural drying, LIBS analysis was performed. The test results of the mixed solution show that plasma with lower electron density and higher electron temperature can be obtained after full drying, the signal intensity will be stronger, and the stability can be reduced to less than 1%. The experimental results of Cu, Cd, Mn, Pb, Cr and Sr as target elements show that the LODs of the MASOM-LIBS method for most elements is less than 0.1 mg/L when the detection time is less than 3 min, which has certain advantages over similar LIBS methods. If the detection time is increased appropriately, the LODs of this method is even expected to be reduced to less than 0.01 mg/L. These results indicate that MASOM-LIBS is a feasible method to improve the sensitivity and speed of the detection of trace heavy elements in liquid samples and can facilitate the wide application of LIBS in water quality monitoring. In view of the short detection time, high sensitivity and low LODs of MASOM-LIBS, this method is expected to be developed into a water trace heavy metal detection technology with fully automatic, real-time, highly sensitive and multi-element detection technology in the future.