Direct determination of nutrient and toxic elements in original kelp by high irradiance laser ionization time-of-flight mass spectrometry

Direct quantitative multi-elemental analysis of kelp was demonstrated with a high irradiance laser ionization time-of-flight mass spectrometer (LI-TOFMS). To eliminate the influence of interfering peaks like peaks of organic fragment ions, the ionization chamber was filled with helium at a low pressure. A certified kelp reference sample was used to check the accuracy of the instrument and establish the linear calibration curve. The detection limits of this method are able to reach μg/g level. It is demonstrated that the intensities of elements are almost linearly proportional to the concentrations of elements in the kelp sample. Three groups of real kelp samples from different sea areas of China was cut into small pieces and analyzed at the same instrumental condition. 18 elements can be determined in 2 min after the sample mounted. The elemental concentration differences of the three samples reflect the possible processing procedure, seawater composition, and coastal environment differences.