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

Abstract

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 solutions with the concentrations of 0.0, 5.0, 10.0, 20.0, 30.0, 40.0 and 50.0 umg / L, and drawing the calibration curves of each elements by using the concentrations as horizontal coordinates and ion abundances as vertical coordinates; and fifth, measuring and calculating the contents of the 16 elements in the food additive citric acid in the sample solution obtained in the thirdstep according to the fourth step.

Description

technical field [0001] The invention belongs to the field of chemistry and is suitable for the determination of 16 elements of lead, copper, iron, arsenic, chromium, zinc, cadmium, manganese, nickel, cobalt, indium, rhodium, gallium, bismuth, neodymium and cerium in food additive citric acid. Background technique [0002] Citric acid (Ctric acid), also known as wolfberry acid, chemical name 2-hydroxypropane-1,2,3-tricarboxylic acid (2-hydroxy-1,2,3-propanetricarboxylic acid), chemical structural formula of citric acid monohydrate: [0003] Citric acid is a colorless crystal at room temperature, has a strong sour taste, and is easily soluble in water. Anhydrous citric acid can be obtained by controlling the appropriate temperature during crystallization. The food additive citric sour tastes sour and mild, and is widely used in beverages, fruit juices, wines, confectionery, flavored foods, canned food, dairy products and other food and beverages, and can also be used as an a...

AI Technical Summary

Problems solved by technology

[0008] According to the national standard "Food Additive Citric Acid" GB1987-2007, the food additive citric acid must be identified, content, moisture, easy charring, sulfate ash, chloride, sulfate, oxalate, calcium salt, iron, arsenic, arsenic The detection of 13 items such as salt, lead, and water-insoluble substances; the national standard "citric acid" GB / T 8269-2006 also stipulates the detection items and requirements of citric acid, and the detection of arsenic and lead in safety and health items is in accordance with the national standard "Food Determination of total arsenic and inorganic arsenic in food" GB / T 5009.11-2003, "Determination of total arsenic and inorganic arsenic in food" GB / T 5009.11-2003, but the detection limit is 1.0mg / kg, lower than 1.0mg / kg undetectable

The content of harmful heavy metal elements such as lead, copper, arsenic, chromium, cadmium, and cobalt in most food additives lemons is less than 1.0mg / kg (1ppm), and the content of some elements is less than 1.0μg / kg (ppb), which is the thousandth of the national standard limit One, or even lower, the existing standards and methods cannot accurately determine its content

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