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

3.
2.
1.
6 Determination

(1) Liquid chromatography conditions

Chromatographic column: Atlantis-C ₁₈ , 3.
5um, 150mm×2.
1mm (inner diameter) or equivalent; column temperature: 40℃; injection volume: 30μL; mobile phase: mobile phase: mobile phase A is 0.
1% formic acid aqueous solution, mobile Phase B is a 0.
1% formic acid acetonitrile solution, and mobile phase C is methanol
.

Table 3-3 Liquid chromatography gradient elution conditions

(2) Mass spectrometry conditions

Ion source: Electrospray ion source (ESI); Scan method: positive ion scan; Detection method: Multiple reaction monitoring (MRM); Electrospray voltage (IS): 5000V; Auxiliary gas (AUX) flow rate: 7L/min; Auxiliary gas Temperature (TEM): 550°C; Focusing voltage (FP): 150V; Mass spectrometry parameters of streptomycin , dihydrostreptomycin and kanamycin are shown in Table 3-4
.

Table 3-4 Mass spectrometry parameters of streptomycin, dihydrostreptomycin and kanamycin

(3) Qualitative confirmation

Choose 1 parent ion and 2 or more product ions for each component to be tested.
Under the same experimental conditions, the retention time of the test substance in the sample and the retention time of the corresponding component in the mixed matrix standard calibration solution are within ±2.
5% In addition, the relative ion abundance of each component in the sample spectrum is compared with the corresponding relative ion abundance in the mixed matrix standard calibration solution spectrum with close concentrations.
If the deviation does not exceed the range specified in Table 1-5, you can Determine the presence of the corresponding analyte in the sample
.

(4) Quantitative determination

External standard method quantification: Under the best working conditions of the instrument, the mixed matrix standard calibration solution of streptomycin, dihydrostreptomycin and kanamycin is injected for determination, and the concentration of the mixed matrix standard calibration solution is taken as the abscissa.
The peak area is the ordinate.
Draw a standard working curve.
Use the standard working curve to quantify the sample to be tested.
The response value of the analyte in the sample solution should be within the linear range determined by the instrument
.

Figure 3-2 Multiple reaction monitoring (MRM) chromatograms of streptomycin, dihydrostreptomycin and kanamycin

Related links: Determination of residual amounts of streptomycin, dihydrostreptomycin and kanamycin in milk powder, milk, puffer fish, eel and royal jelly, sample pretreatment