Determination method of quinolone drug residue analysis technology (5)

(8) Immunoassay (Immunoassay, IA)

The immunological analysis method is based on the specific reaction of antigen and antibody, and is known for its high specificity and high sensitivity.
It can simplify the analysis process and is suitable for the analysis of trace components in complex matrices
.

The QNs structure contains carboxyl groups, so the carboxyl groups are often used to react with the free amino groups of the carrier protein, and the QNs and the carrier are connected to synthesize artificial antigens, and then the animals are immunized to produce specific antibodies

1) Enzyme-linked immunosorbent assay (enzymelinkimmunosorbent assay, ELISA)

ELISA has been widely used in rapid screening and detection of veterinary drugs and pesticide residues
.

Most ELISA methods use enzymes as markers, but there are also methods established using other markers, such as chemiluminescence and electrochemistry

Jiang Jinqing et al.
established an ELISA method for simultaneous detection of multiple QNs
.

The CIP artificial antigen was synthesized by two-step carbodiimide (EDC) method, and New Zealand white rabbits were immunized to prepare polyclonal antibodies, and an ELISA method for the detection of multi-residue QNs drugs was established

The SAR monoclonal antibodies prepared by Huet et al
.

have cross-reactivity to 15 QNs such as SAR, NOR, and FLU .

2) Colloidal gold-based immunochromatographi cassay (CGIA)

CGIA is a new type of immunolabeling technology developed in the 1970s that uses colloidal gold as a marker to combine with various macromolecular substances such as proteins, and then use antigen-antibody reactions to achieve the purpose of detection
.

Colloidal gold technology has the advantages of convenience and speed, strong specificity, sensitivity, strong stability, no need for special equipment and reagents, and intuitive result judgment.

3) Chemiluminescence enzyme-linked immunoassay (CLEIA)

CLEIA is composed of two parts: chemiluminescence analysis system and enzyme-linked immunoreaction system
.

The chemiluminescence analysis system means that a chemiluminescent substance or enzyme releases a large amount of free radicals through catalytic oxidation reaction to form an unstable excited state intermediate.

4) Fluorescence polarization immunoassay (FPIA)

Compared with the ELISA method, FPIA simplifies the operation steps and shortens the operation time.
It converts the heterogeneous reaction system into a homogeneous reaction system.
It is a simple, reliable, fast and efficient immunoassay method
.

Mi et al.

5) Magnetic particle-based enzyme immunoassay (MPEIA)

MPEIA applies magnetic particles to ELISA, replacing the traditional solid-phase carrier of the ELISA plate, and uses the principle that magnetic beads can be separated under a magnetic field.
The magnetic particles are connected with monoclonal antibodies, which are immunomagnetic beads.
After the detection of the antigen is bound, under the action of a magnetic field, the specifically bound antigen is separated from other unreacted substances, and finally the antigen content is determined by enzyme-linked immunochromogenic reaction
.

MPEIA overcomes some shortcomings in common ELISA assays and is more advantageous

Related Links: Determination Method of Quinolone Drug Residue Analysis Technology (4)