Conventional methods for the determination of residual β-agonist drugs (4)

1.

(1) Selection of extraction and purification conditions

1) Selection of extraction solvent

The extraction methods of β-stimulants mainly include liquid-liquid extraction and solid phase extraction (SPE)

Hydrolysis mainly includes acid hydrolysis and enzymatic hydrolysis

The common extraction solvents for β-agonists in the samples are methanol, ethyl acetate , tert-butyl methyl ether , ethyl acetate-isopropanol, ethyl acetate- n-butanol and so on

Table 1-6 Different ratios of ethyl acetate-isopropanol mixed solvent extraction and recovery of β-stimulants (addition level 5.

2) Choice of pH

Based on the fact that β-agonists are soluble in aqueous solutions under acidic conditions and in organic solvents under alkaline conditions, in this experiment, 12 kinds of β-agonists are used in sodium acetate buffers (0.

Figure 1-6 Extraction and recovery of β-stimulants at different pH

3) Purification method

The most commonly used purification methods for β-stimulants are solid phase extraction (SPE), immunoaffinity chromatography (IAC), and liquid-liquid purification

4) The influence of the filter membrane

The standard solution containing 12 kinds of β-stimulants was passed through 0.

Figure 1-7 Elution curve of 12 kinds of β-stimulants on MCX and SCX solid phase extraction columns.

5) Matrix interference experiment

Because the impurities in the sample liquid have a certain matrix effect on the detection of β-agonist drugs, the standard curve in this method is all diluted and configured with the extract of the blank matrix

(2) Selection of instrument conditions

1) Comparison of internal standard method and external standard method

Due to the relatively large differences in the structure of the 12 compounds analyzed, the internal standard method and the external standard method were compared quantitatively in the study.

2) Determination of testing conditions

According to the general requirements of mass spectrometry, first perform a full scan for each compound, and then determine the scan ion for each compound, and use the selected ion mode to improve its detection sensitivity

Among the analyzed compounds, the polarity of each substance is different.

Related Links: Public method for determination of residual β-agonist drugs (3)