VERIFICATION OF THE MEASUREMENT RESULTS LIGHT SCATTERING METHOD FOR PARTICLES SIZE DETERMINATION

• Main Author: Rinaldo, Arwi
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/53138
• Institution: Institut Teknologi Bandung

The light scattering technique is used for particles characterization which are in the order of nanometers to millimeters. In medicine, this technique can be used to characterize crystalline particles carried by urine which, then, used to diagnose people with kidney stones. This study aims to verify the results of the measurement of the light scattering method in particle size determination. The light source used is a Helium-Neon laser light with a wavelength of 633 nm. the sample of particles used was Polystyrene Latex with an average diameter of 100 nm. The particles dissolved in NaCl with each concentration of 0.025%, 0.05%, 0.5%, and 5% yielded particles with an average diameter of 104.2 nm, 101.9 nm, 128.9 nm, 1930 nm respectively with the experiments were carried out 3 times at each concentration. The data obtained was initially examined by preprocessing data in three steps of moving averages, normalization, and shifting. Data analysis without Fourier transform shows an inversely proportional relationship between the diameter of the particles and the distribution of the light curve of the center of the diffraction pattern formed. Particles with each diameter of 101.9 nm, 104.2 nm, 124.9 nm, and 1930 nm have standard deviations of 4.1351 mm, 4.1564 mm, 4.0068 mm, and 4.0454 mm respectively. Furthermore, the data were processed by using Fourier transformation with the Power Spectral Density method. This method determines the threshold power of the wavenumber to pass. The threshold selected was 4.2 V2 mm removing wavenumber greater than ± 0.2 mm-1 and 8 V2 mm removing wavenumber greater than ± 0.1 mm-1. The analysis carried out is the comparison of the peak value, the ratio between the central maximum and the first maximum, the width of the curve distribution, and the ratio of the curve distribution. The ratio of the central maximum peak to the first bright peak produces a straight relationship with the diameter of the Polystyrene Latex particles. Where the 101 nm diameter has a ratio of 2.736, the 104 nm diameter has a ratio of 2.865, the diameter 124.9 nm has a ratio of 2.957 and the diameter 1930 nm has a ratio of 2,970.