Method for measuring various elements in food additive citric acid through ICP-MS

The invention belongs to the field of chemistry, and particularly relates to a method suitable for measuring 16 elements including lead, copper, iron, arsenicum, chromium, zinc, cadmium, manganese, nickel, cobalt, indium, rhodium, gallium, bismuth, neodymium and cerium in a food additive citric acid. The measuring method consists of the following steps: firstly, weighing a sample of the food additive citric acid, and putting the sample in a microwave digestion instrument; secondly, performing sample digestion by using a mixed acid of nitric acid and perchloric acid; thirdly, adding a sample solution into hyperpure water according to a proportion that 1 to 2 mL of the nitric acid is added into each 10 grams of the citric acid sample, and moving the mixture into a plastic volumetric flask of100 mL; fourthly, drawing calibration curves: using national standard stock solutions (GBW) containing the 16 elements, using 3 percent nitric acid to dilute the national standard stock solutions into mixed standard solution