Determination of 18 sulfonamide residues in royal jelly. Liquid chromatography-tandem mass spectrometry (2)

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6 Determination

(1) Liquid chromatography conditions

Chromatographic column: Atlantis C ₁₈ , 3um, 150mm×2.
1mm (inner diameter) or equivalent; mobile phase: A is acetonitrile, B is 0.
1% formic acid aqueous solution, and C is methanol
.

(2) Mass spectrometry conditions

Ion source: electrospray ion source: scanning method: positive ion scanning; detection method: multi-reaction monitoring; electrospray voltage: 5500V; atomizing gas pressure: 0.
076MPa; curtain air pressure: 0.
069MPa auxiliary gas flow rate: 6L/min: Ion source temperature: 350℃: See Table 2-6 for qualitative ion pair, quantitative ion pair, collision gas energy and declustering voltage
.

(3) Liquid chromatography-tandem mass spectrometry determination

Samples were injected with matrix standard working solution, and the ratio of the peak area of ​​each standard to the peak area of ​​the internal standard was taken as the ordinate, and the ratio of the concentration of each standard working solution to the concentration of the internal standard solution was taken as the abscissa.
Draw the standard working curve and work with the standard The curve quantifies the sample, and the response values ​​of the 18 sulfonamides in the sample solution should all be within the linear range determined by the instrument
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7 Selection of analysis conditions

(1) Selection of sample extract

Three different solutions were used as the royal jelly sample extracts, and the royal jelly sample recovery rate experiment was carried out at the same addition level and the same experimental conditions.
The experimental data are shown in Table 2-10.

Table 2-10 Comparison of recovery rates of different extracts (%)

From the data in Table 2-10, it can be seen that when 0.
1mol/L hydrochloric acid is used as the extractant, the recovery rate after internal standard correction is between 60.
0% and 369%, especially for sulfapyridine, sulfa-p-methoxypyrimidine , and sulfapyridine.
The recovery rates of dimethyl pyrimidine , sulfamethoxazine, sulfamethoxine, sulfafenpyrazole, sulfaquinoxaline, sulfafenac and sulfachloropyrazine all exceeded 150%
.

(2) Determination of the pH of the extract

For the establishment of a pre-veterinary drug multi-residue method, it is very important to choose a suitable pH sample extraction solution, because the pH of the sample solution is different when the target substance of different pH is passed through the column.
In order to find the sulfa drugs that pass Oasis MCX The optimal pH of the column.
After the royal jelly sample is precipitated with trichloroacetic acid, the pH of the extract is 1.
0.
Adjust the extract to four different pHs: pH=1.
0, pH=2.
0, pH=3.
0, and pH=4.
0.
Under the same other conditions, a recovery experiment was carried out.
The experimental data are listed in Table 2-11
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Table 2-11 Comparison of recovery rates of different pH extracts (%)

Related Links: Determination of 18 Sulfa Residues in Royal Jelly Liquid Chromatography-Tandem Mass Spectrometry (1)