Puribang | Determination of carbamate pesticides and their metabolite residues in plant-derived foods

a common group contained in the structure of a carbamate pesticide

The structural formulas of the ten analytes are listed in USEPA Method 531.1 as follows (including 1-naphthol and internal standard BDMC). They are listed in the order of the flow on the C18 column. Except for 1-naphthol, all contain an N-methylcarbamoyl moiety (represented by OR).

Method principle:

The carbamate pesticide separated by a C18 column or a C8 column is first hydrolyzed by NaOH at 100 ° C to release alcohol, carbonate and jiaamine.

In the second post-column reaction, jiaamine reacts with o-phthalaldehyde (OPA) and 2-thioethanol to form a 1-methyl-2-indole compound with strong fluorescence absorption, which is detected by a fluorescence detector and has Very low detection limit.

Method establishment:

Using Pribolab MDS 3100 multi-function photoelectric derivative system with Shimadzu liquid phase and fluorescence detector, the experiment was carried out according to GB 23200.112-2018. The experimental conditions are as follows:

Column: 250mm × 4.6mm, 5um

Excitation wavelength: 330nm emission wavelength 465nm

Post-column derivatization hydrolysis flow rate: 0.3 mL/min derivatization flow rate 0.3 mL/min, hydrolysis temperature 100 ° C Derivation temperature 40 ° C

The hydrolyzate and the derivative liquid are all configured according to GB 23200.112-2018, and the gradient table is as follows:

Repeatability verification:

The high- and low-concentration mixed standards were continuously injected with 6 needles, and the peak area variation was less than 7%, and the repeatability was good.

Using the instrument