Mohamad Infrawan Yulianto Ichwan, Hery Suyanto, Maria Margaretha Suliyanti, Rinda Hedwig, Marincan Pardede, Kiichiro Kagawa, Tjung Jie Lie, Koo Hendrik Kurniawan

This paper appears in:  Proceeding ITB Engineering Science 37B

Issue Date:  2 May 2005
On page(s): 49 – 65

 

Abstract

A new approach of quantitative analysis of liquid sample using laser ablation technique was developed. The liquid was immediately freezed using the mixture of dry ice and alcohol in weight ratio of 95% : 5%. As a result, an increase of the repulsion force from the sample surface will enable the generation of the laser-induced shock wave plasma which was difficult to carry out on liquid surface. The ice sample was then irradiated using Nd-YAG laser operated in its fundamental wavelength. In order to increase the signal to background ratio and to obtain a sharp atomic spectra, helium gas was used instead of air. Dynamic characterization of the spatially integrated time profil of the Cu I 521.8 nm, Cu I 510.5 nm and Hα lines shows a shock excitation stage and cooling stage which is corresponded to our shock wave model even when the plasma was generated under atmospheric pressure. Further study of the time profile averaged temperature of the atmospheric plasma also shows an increase of temperature during the cooling stage. An application of this technique was then applied to quantitative analysis of several liquid samples. A linear calibration curve which intercept at 0 point was obtained for all of the elements investigated in this study such as sodium, potassium, lithium, copper, silver, lead and aluminum. A detection limit of around 1 pp, was found for the above element. This new technique will contribute to a great extent of laser atomic emission spectrochemical analysis for liquid samples.