Emission Spectral Profile of Salt in Laser-Induced Breakdown Spectroscopy (LIBS) on River Clamshell Sample

Since the river clamshell is commonly used as one of the raw materials for making lime betel widely consumed, inspection of its salt content is very important. This work is to study the profile of salt emission spectrum from the river clamshell sample inlaser-induced breakdown spectroscopy (LIBS). The observation of the general emission profile is possible thanking to the availability of the optical multichannel analyzer (OMA) system with a wide wavelength coverage from 200 nm-950 nm. LIBS apparatus used in this work consist of Nd-YAG (neodymium-doped yttrium aluminum garnet) laser and an OMA system equipped with an echelle spectrograph system. The river clamshell samples were collected from Panga River, Panga, Aceh Jaya, Aceh, Indonesia. The Panga river up streams to mountain of Gunong Ujeun, used to an intensive traditional mining location. The plasma generation was made by focusing the Nd-YAG laser beam on the clamshell sample under air surrounding gas at atmospheric pressure. There are two kinds of sample used, namely fresh sample without any treatment and pelletized sample. The result shows the emission spectrum in general consist of a large number of Ca emission lines, both atomic and ionic lines. However, several other salt emission lines such as Mg, Na, K, and Al also can be clearly observed at various wavelengths. This result suggests the emission spectrum of salt detected from the river clam sample are predominantly dominated by Ca emission lines.