Studies Of Laser Induced-breakdown Spectroscopy Of In Edible Gelatin

Laser-induced breakdown spectroscopy (LIBS) is a new atomic emissionspectrum analysis technique since the late20th century. When a powerful laser pulseis focused on the surface of material to be analyzed, the material is vaporized andplasma is formed. Taking advantage of the high sensitivity of a spectrometer, theplasma emission spectrum can be analyzed. By analyzing the spectrum, theinformation such as the element composition and the content of the material can beobtained.The development of LIBS technology, the basic theory of LIBS and quantitativeanalysis methods were reviewed in the thesis. By using spectroscopy analysis method,we focused on studying the spectrum of plasma emission of edible gelatin, andselected the CrI:425.43nm as analytical spectral line. Besides, the temperature andelectron density of the laser induced edible gelatin plasma were calculated. Weanalyzed the influence of the delay time of detection on spectrum. Utilizing therelationship of the ratio of signal to background and the intensity of signal, theoptimum condition was found. We investigated plasma shielding effect on thespectrum. With a set of five samples of edible gelatin, calibration curve was presentedusing two quantitative analysis methods. The experimental results indicate that theinternal standard method is better than the intensity calibration method. Because it isvery difficult to find the standard sample of edible gelatin in practical applications, thecalibration-free method was preliminarily studied.