Method for simultaneously measuring fatty acid contents in food for special medical purposes

Abstract

The invention discloses a method for simultaneously measuring fatty acid contents in food for special medical purposes. The method is characterized by including the steps: 1) performing pretreatment on a sample to be measured of the food for special medical purposes for standby application; 2) placing the sample after pretreatment into a gas chromatograph-mass spectrometer and measuring the sample by selected ion scanning gas chromatography-mass spectrometry; 3) detecting the chromatographic peak area of fatty acid methyl ester by an FID (flame ionization detector). Chromatographic conditions include that the fixed phase of a chromatographic column is poly-dicyan propyl polysiloxane, carrier gas is nitrogen, the flow rate of the carrier gas is 0.4mL-0.6mL / min, the temperature of a sample injection port ranges from 240 DEG C to 260 DEG C, split ratio is (25-35):(1-2), sample injection quantity is 1.0 microliter, the initial temperature of the column is 140 DEG C and kept for 5 minutes, temperature rise rate is 3-5 DEG C / min, and the temperature rises to 240 DEG C and is kept for 30 minutes. By the measuring method, RSD (relative standard deviation) values are effectively reduced, accuracy of sample measuring results is ensured, and measured data are real, stable and reliable.

Description

technical field [0001] The invention belongs to the field of medical inspection and is mainly used for the determination of fatty acid content of special medical formula food, which can improve the accuracy of the determination result. Background technique [0002] Formula food for special medical purposes, the dosage form is mostly suspension or powder, the product matrix is ​​not uniform, the composition is complex, and the content determination requires different degrees of pretreatment process; and this method belongs to the content determination of fatty acid methyl ester, there are 37 types There are so many types, it is more difficult to require the type of chromatographic column, chromatographic conditions, pre-treatment, and the level of operators, which will have a certain impact on the accuracy of the result data. [0003] The existing method for the determination of fatty acid content in formula foods for special medical purposes is mainly the gas phase method, w...

AI Technical Summary

Problems solved by technology

[0010] 1. Boron trifluoride methanol solution has 14%, 10%, 15% and other concentrations, 14% and 15% are more commonly used, in which boron trifluoride and methanol are complexed at a ratio of 1:1, and boron trifluoride is in The process of methyl esterification acts as a catalyst. Methanol alone cannot methyl esterify saponified fatty acids in a short period of time. Sodium hydroxide methanol solution-boron trifluoride methanol solution system is used in the saponification of fat and methyl esterification of fatty acids. Although the time for some fatty acid methyl esterification is shortened, boron trifluoride has problems such as high toxicity and subsequent waste liquid treatment, and it needs to add liquid twice during the operation, which adds uncertain factors and safety hazards to operators.

[0011] 2. The chromatographic conditions may be slightly different due to column manufacturers, fillers or different instruments in the actual measurement, and the carrier gas flow rate is not specified in the conditions. In the actual measurement process, the difference in the carrier gas flow rate will directly affect several Separation of key peaks

[0012] 3. The qualitative research on the target peaks of 37 fatty acid methyl esters is based on the injection of a single standard solution of fatty acid methyl esters and the mixed standard solution of fatty acid methyl esters for matching and checking. Troublesome handling, difficulty in purchasing single-standard solutions, and strict storage requirements may affect the accuracy of subsequent sample determinations