Spectrochemical analysis of powder using 355 nm Nd-YAG laser-induced low-pressure plasma

Abstract

The applicability of spectrochemical analysis of minute amounts of powder samples was investigated using an ultraviolet Nd-YAG laser (355 nm) and low-pressure ambient air. A large variety of chemical powder samples of different composition were employed in the experiment. These included a mixture of copper(II) sulfate pentahydrate, zinc sulfide, and chromium(III) sulfate n-hydrate powders, baby powder, cosmetic powders, gold films, zinc supplement tablet, and muds and soils from different areas. The powder samples were prepared by pulverizing the original samples to an average size of around 30 microm in order to trap them in the tiny micro holes created on the surface of the quartz subtarget. It was demonstrated that in all cases studied, good quality spectra were obtained with low background, free from undesirable contamination by the subtarget elements and featuring ppm sensitivity. A further measurement revealed a linear calibration curve with zero intercept. These results clearly show the potential application of this technique for practical qualitative and quantitative spectrochemical analysis of powder samples in various fields of study and investigation.

Rapid Analyses of Tiny Amounts of Powder Samples Using Transversely Excited Atmospheric CO2 Laser-Induced Helium Gas Plasma with the Aid of High-Vacuum Silicon Grease as a Binder on a Metal Subtarget

“…It is known that low-cost gold foils containing silver (Ag) and copper (Cu) as impurities are also available on the market because of the high cost of high-purity gold foil. 13 Using this technique, we confirmed that the impurity emission lines of both Ag and Cu in high-purity gold foil are greatly suppressed, as shown in Fig. 7b.…”

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

“…Further measurement on a number of the standard soil samples of various Pb contents were shown to yield a linear calibration line with practically zero intercept and a detection limit of < 10 ppm. Despite the favorable results reported in the previous studies [19,20], the generation of shock wave plasma was only indicated by the plasma emission characteristics, leaving its direct detection and the underlying plasma excitation mechanism less than appropriately addressed.…”

“…The resulted spectra is presented in Fig. 5, (a 19 for the low pressure and atmospheric pressure He gases. One may therefore assumed the existence of local thermal equillibrium (LTE) condition for the application of the two-lines method.…”

“…An alternative method of handling powder sample was introduced in 2007 by trapping the powder in a quartz subtarget having a random distribution of micro holes on its surface [19]. The micro holes were fabricated with diamond powder of 30 μm diameter which resulted in micro holes of roughly 30 μm diameter and 30 μm depth on the quartz surface.…”

A novel procedure of powdered samples immobilization and multi-point calibration of LA ICP MS

“…There are several procedures commonly used for this purpose: (i) fusion with lithium borate; [9][10][11] (ii) the use of methacrylate glue; 12 (iii) the use of a sol-gel technique; 13 (iv) pellet formation by means of manual pellet press; 4,14-20 and (v) trapping powdered sample in the tiny microholes on the quartz target. 21 The common step of all those procedures is grounding and homogenizing of the solid sample. The differences lie in the type of binder used for powder immobilization, the need to press the target, time of sample preparation and the long-term stability of the obtained target.…”