A novel gold particle-based paper sensor for sensitively detecting carprofen in bovine muscle

Figures & data

Figure 1. Schematic illustration of the immunochromatographic lateral flow strip test.

Figure 2. The UV/Vis spectra of immunogen (a) and coating antigen (b).

Figure 3. The subtype of 1F5-C8 (a) and the standard curve of CAR detection by the ic-ELISA in PBS (b).

Table 1. The cross-reaction of CAR with other compounds by ic-ELISA in bovine muscle samples.

Compounds	Structures	IC50 (ng g^−1)	Cross-reactivity (%)
CAR		0.106	100
ASP		> 1.0 × 10^4	< 0.001
FLU		> 1.0 × 10^4	< 0.001
DIC		> 1.0 × 10^4	< 0.001
KET		> 1.0 × 10^4	< 0.001
TOL		> 1.0 × 10^4	< 0.001

Table 2. The optimized experimental parameters of the test strip.

Parameters	Results
Coating antigen	CAR-OVA
Coating concentration (T line)	0.3 mg mL^−1 (55 ng cm^−1)
Gold-mAb concentration	12.5 µg mL^−1 (75 ng cm^−1)
Buffer for competition reaction	PBS (containing 10% methanol)
pH of competition reaction	7.4

Figure 4. The bovine muscle samples with multiple concentrations of CAR were analysed by the immunochromatographic strips (a, 1 - 7: 12.50, 6.25, 3.13, 1.57, 0.79, 0.40 and 0 ng g⁻¹). The standard curve of CAR detection by the immunochromatographic strips (b).

Table 3. Recoveries and CVs of the test strips for CAR spiked into bovine muscle samples.

	Spiked CAR (ng g^−1)	Tested CAR (ng g^−1)	Recovery (%)	CV (%)
Intra-assay	1	0.83 ± 0.05	82.51 ± 4.83	5.85
	3	2.54 ± 0.19	84.62 ± 6.17	7.29
	5	4.53 ± 0.32	90.55 ± 6.49	7.17
Inter-assay	1	0.80 ± 0.05	79.53 ± 4.90	6.16
	3	2.52 ± 0.22	83.84 ± 7.39	8.81
	5	4.38 ± 0.31	87.58 ± 6.21	7.09