Development of an immunochromatographic strip for the rapid detection of 10 β-agonists based on an ultrasensitive monoclonal antibody

Figures & data

Figure 1. Schematic illustration of the strip.

Figure 2. Synthesis of the sal-hapten.

Figure 3. Polyacrylamide gel electrophoresis image of coating antigens (1: OVA; 2: sal-hapten-OVA).

Table 1. Cross-reactivity of related structural analogs.

Chemicals	Structure	IC50 (ng/mL)	CR (%)
Salbutamol		1	100
Clenbuterol		1.2	83.3
Cimaterol		>5	<20
Brombuterol		2	50
Mabuterol		3	33.3
Terbutaline		5	20
Clenpenterol		5	20
Carbuterol		5	20
Mapenterol		5	20
Pirbuterol		>5	<20
Progesterone		>100	<1%
Biotin		>100	<1%
Diethylstilbestrol		>100	<1%

Table 2. Detection limit of sal by other methods.

Method	ELISA	LC-MS	HPLC	UPLC
Limit of detection (LOD, ng/mL)	0.02	1.5	0.02	0.01

Figure 4. Tolerance of 3G10 for different urines.

Figure 5. The sensitivity of the immunochromatographic assay in urine (1, sal; 2, clenbuterol; 3, cimaterol; 4, brombuterol; 5, mabuterol; 6, terbutaline; 7, clenpenterol; 8, carbuterol; 9, mapenterol; 10, pirbuterol).

Figure 6. Analysis of sal concentration with strip (1, 0 ng/mL; 2, 1 ng/mL; 3, 2 ng/mL; 4, 5 ng/mL; the strip cut-off completely at 5 ng/mL of sal).

Table 3. Comparison of sal by ic-ELISA and immunochromatographic strip in the swine urine (n = 3).

Samples	Spiked level (ng/mL)	Detected by ic-ELISA			Detected by strip
		Mean (ng/mL) ± SD	Recovery (%)	CV (%)	Test line
Swine urine	0	0.10 ± 0.012	/	0.70	+++
	1	1.11 ± 0.069	111	5.11	++
	2	2.35 ± 0.054	117	6.35	+
	5	5.58 ± 0.041	112	4.12	---

Note: +++, negative sample; ++, sal concentration is 1 ng/mL approximately; +, sal concentration is 2–4 ng/mL; ---, sal concentration is more than 5 ng/mL; /, no recovery.