Determination of 9 kinds of penicillin residues in puffer fish and eels

5.
2.
3.
6 Determination

(1) Liquid chromatography conditions

Chromatographic column: ZORBAX SB-C ₁₈ , 3.
5 um, 150 mm℃ 2.
1 mm (inner diameter) or equivalent; see Table 5-20 for mobile phase composition, flow rate and gradient program; column temperature: 30℃; injection volume: 20 μL
.

Table 5-20 Mobile phase gradient program and flow rate

(2) Mass spectrometry conditions

Ion source: electrospray ion source; scanning method: positive ion scan; detection method: multi-reaction monitoring; electrospray voltage: 5500 V; atomizing gas pressure: 0.
055 MPa; curtain air pressure: 0.
079 MPa; auxiliary gas flow rate: 6L/ min; Ion source temperature: 400℃; qualitative ion pair, quantitative ion pair and declustering voltage (DP), collision gas energy (CE) are shown in Table 5-6
.

(3) Qualitative determination

Select one parent ion and two or more product ions of each substance to be tested.
Under the same experimental conditions, the retention time of the substance to be tested in the sample is within ±2.
5% of the retention time of the corresponding substance in the matrix standard solution; Comparing the relative abundance of each qualitative ion in the sample spectrum with the relative abundance of the ion in the matrix standard solution whose concentration is close, the deviation does not exceed the range specified in Table 1-5, it can be determined that there is a corresponding test in the sample Things
.

(4) Quantitative determination

Use a blank sample to add a standard mixed working solution for injection separately, and draw a standard working curve with the concentration of the standard working solution as the abscissa and the peak area as the ordinate
.

Figure 5-6 Multiple reaction monitoring (MRM) chromatograms of 9 penicillin standard substances

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