Determination of residual amounts of streptomycin, dihydrostreptomycin and kanamycin in milk powder, milk, puffer fish, eel and royal jelly

4) Selection of eluent

The solid phase extraction column was rinsed with 10 mL methanol water of different concentrations as the eluent, and the optimal methanol concentration of the eluent was selected.
The experimental data are shown in Table 3-9
.

Table 3-9 The influence of different concentrations of methanol water as eluent on the results

It can be seen from Table 3-9 that 10 mL of 25% methanol water as eluent can effectively remove impurities and eliminate matrix interference.

5) Selection of eluent

This method uses C ₁₈ chromatographic column, and the retention effect of aminoglycoside drugs on C ₁₈ chromatographic column is not ideal, so add sodium heptane sulfonate as ion pair reagent in constant volume solution to enhance its performance on C ₁₈ chromatographic column.
Keep, the experimental data is shown in Table 3-10
.

Table 3-10 The effect of different concentrations of sodium heptane sulfonate as a constant volume solution on the results

As a weak cation exchange column, the carboxyl column needs to be eluted under acidic conditions.

Table 3-11 The influence of different concentrations of formic acid 0.
01mol/L sodium heptane sulfonate as eluent on the results

It can be seen from Table 3-10 and Table 3-11 that 2mL 4% formic acid 0.
01mol/L sodium heptanesulfonate aqueous solution is used as the eluent, and the recovery rate of the three antibiotics is the highest, and 2mL 4% formic acid 0.
01mol/L heptane The sodium alkane sulfonate aqueous solution can completely elute the analyte from the carboxyl column, and it can be directly passed through the membrane for testing without concentration
.

(2) Selection of measurement conditions

1) Selection of liquid chromatography conditions

This method selects ZORBAX SB-C ₁₈ (3.
5um, 150 mm×2.
1 mm), Atlantis-C ₁₈ (3um, 150 mm×2.
1 mm) and Symmetry-C ₁₈ (3um, 150mm×2.
1mm) three liquid phase analysis The column was tested, and the detection sensitivity and separation effect of the three columns streptomycin , dihydrostreptomycin and kanamycin were compared.
As a result, it was found that the Atlantis-C ₁₈ analytical column had better sensitivity and resolution
.

2) Selection of mass spectrometry conditions

Take the standard 10μg/mL of streptomycin, dihydrostreptomycin and kanamycin, and inject the standard solution into the ion source at a flow rate of 10uL/min to find qualitative and quantitative ion pairs.

Related links: Selection of analytical conditions for determination of residues of streptomycin, dihydrostreptomycin and kanamycin in milk powder, milk, puffer fish, eel and royal jelly