Development Of Laser-Induced Breakdown Spectroscopy Technique For The Analysis OF Fish Samples From The Arabian Gulf
Mohammad Gondal, لطفي مليادي سرشمان
كلية العلوم-جامعة الملك فهد للبترول والمعادن · السعودية
A Laser Induced Breakdown Spectroscopy set-up was used to detect and analyze different elements in a variety of fish samples purchased from the local market. Toxic elements may be present in the fish from environmental contaminations, such as those arising from industrial discharges, oil spills and agricultural pollution. The fish samples were completely dried, ground into fine powder and subsequently pelletized using the pressing machine with a pressure of 6 bars for dry samples, 2 bars for wet samples, and 4 bars for medium condition. Signal intensity optimization, especially the optimum time delay, was first investigated. By using fish samples with the same dimension and maximum incident laser energy, the optimum time delay was approximately 100-125 ns. The study of local thermodynamic equilibrium and optically thin plasma conditions, along with estimating the electron number density and electron temperature, were conducted to make sure the Mc-Whirter criterion holds for the plasma. This is to ensure that the laser – induced plasma generated for our analysis is thin enough to overcome the self-absorption problem, which would yield an accurate system capable of detecting the elemental concentrations with better accuracy and improved limit of detection. Once the system was optimized, it was applied for detecting the presence of a variety of elements in the fish samples. It is worth mentioning that we successfully detected nutrients like Calcium, Magnesium, and Potassium, some heavy elements like Iron, Barium and Manganese and toxic element like Mercury inside the fish samples. The electron temperature and electron density generated by the laser-induced plasma was estimated to be T=14137.55±3448.29 K and 4.2764×〖10〗^16cm-3 respectively. To evaluate the human health risk assessments for the fish consumption, estimated daily intake, target hazard quotient and hazardous index were calculated based on average body weight, fish consumption rate and life expectancy of people (male and female) in Saudi Arabia.