부산대학교 도서관

An easy analytical technique to determine the trace element composition of pumpkin seeds by energy dispersive X-ray florescence (XRF) analysis has been developed. Since the trace element compositions of pumpkin seeds reflect the characteristic compositions of the cultivation soils (i.e., the geographic origin of the pumpkin), the XRF technique was used to distinguish between pumpkins grown domestically and abroad. Pumpkin seed samples produced in Japan or imported from New Zealand, Mexico, and Tonga were used as samples, and were freeze-dried and pressed into disks after pulverization. The measurement conditions of an XRF spectrometer equipped with 3-dimentional polarization optics were optimized to carry out accurate quantitative analysis. As a result, linear calibration curves were obtained, and the measured concentrations of a standard sample were in good agreement with those determined by ICP-AES/MS analysis. A total of 118 pumpkin samples were analyzed quantitatively and the results were subjected to multivariate analysis for 12 elements (P, Ca, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Mo, Ba) to discriminate the four geographical origins. LDA models were established based on the results, allowing the discrimination of the four origins of the pumpkin seeds with 70∼80% accuracy. The present study shows the advantages of XRF analysis, which only requires an easy sample preparation procedure, over ICP-AES/MS analysis. We foresee future applications of the XRF technique to the widespread analysis of foods.