Method for determining sodium content in food by sub sensitivity line atom absorption spectrum

Abstract

The invention belongs to the technical field of a food detection method, particularly relates to a method for determining the sodium content in food by a sub sensitivity line atom absorption spectrum. The method comprises the following steps of 1, sample digestion; 2, determination: (1) setting the parameters of an atomic absorption spectrometer, wherein the absorption wavelength of the atomic absorption spectrometer is set to be 330.24nm; (2) drawing a standard curve; (3) sodium content determination. Compared with the prior art, the method provided by the invention has the advantages that a sample pretreatment method is improved; a microwave digestion method is increased and optimized for replacing wet process digestion, so that the pretreatment is safe, convenient, fast and efficient. Through the use of the sub sensitivity line (330.24 nm) of sodium elements, the work conditions of an instrument is regulated and optimized; the determination is performed by a flame atom absorption spectrum method; the linear range is wide (1 to 50 mug / mL); the accuracy is high; the sample does not need to be diluted for many times; the sample mass detection efficiency is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of food detection methods, and in particular relates to a method for measuring sodium content in food by subsensitive line atomic absorption spectrometry. Background technique [0002] Sodium is an indispensable nutrient element for the human body, which can maintain the normal osmotic pressure and metabolism of the body, and is of great significance to the human body. However, excessive intake of sodium can also easily lead to chronic diseases such as high blood pressure. The national food safety standard GB28050-2011 "National Food Safety Standard Prepackaged Food Nutrition Labeling General Principles" regards sodium as one of the core nutrients, requiring mandatory labeling of its content and the percentage of the nutrient reference value on the label, which is convenient for consumers to take as sodium intake. Therefore, the determination of sodium content in food is of great significance. [0003] The...

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Problems solved by technology

[0003] The current national standard GB / T 5009.91-2003 "Determination of Sodium and Potassium in Food" recommends the test method of sodium element as the pretreatment of wet digestion. Acid consumption is large, and the perchloric acid used has strong oxidizing and corrosive properties, and there is a danger of explosion when mixed with certain substances at high temperatures. In addition, wet digestion also has disadvantages such as long time consumption and the need for personnel to be on duty, which is not enough Safe, convenient and efficient

Sodium is a very active element in chemical properties. Its characteristic wavelength is 589.0nm. The instrument has high sensitivity, high signal intensity and high light absorption value during measurement. It is easily interfered by ionization in the flame. The standard of atomic emission spectrometry recommended by national standards The curve is only linear in a lower and narrow concentration range (1-4μg / mL). Since the sodium concentration in food is usually high, many samples must be diluted multiple times before detection, which is particularly cumbersome for the detection of a large number of samples , at the same time, a large dilution factor is also likely to cause errors

In flame atomic absorption spectrometry, if the characteristic wavelength of the element is used as the analysis line, the sensitivity is too high, which is also not conducive to detection

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