Shock wave plasma generation in low pressure ambient gas from powder sample using subtarget supported micro mesh as a sample holder and its potential applications for sensitive analysis of powder samples

We present in this report the results of experimental study on the spectrochemical analysis of powder samples using subtarget supported micro mesh (SSMM) sample holder in low pressure ambient gases. The study is substantiated by establishing the analyte excitation mechanism with the evidence of shock wave plasma generation and the high temperature induced subsequently required for the thermal excitation and emission of the ablated atoms. The application of SSMM sample holder using Cu subtarget and stainless steel micro mesh to a number of powder samples in low pressure ambient gases are shown to produce generally sharp emission lines with low background, without suffering from intensity reduction and matrix effect commonly found in the use of pelletized powder samples. The same excellent spectral quality is demonstrated by its application to the analysis of rice samples which is the major staple diets in a large number of countries. In particular the analysis of Zn in rice is shown to exhibit a linear calibration line with extrapolated zero intercept and a detection limit of<0.87 ?g/g which is promising for quantitative analysis.