Ultrasensitive indirect competitive ELISA and strip sensor for detection of furazolidone metabolite in animal tissues

Figures & data

Figure 1. Tissue-bound AOZ formation by metabolism, HCl hydrolysis and AOZ derivatization to produce target analyte which could be recognized by the antibody.

Figure 2. Schematic illustration of the strip sensor.

Figure 3. Standard curve obtained by ELISA.

Table 1. Recovery results in spiked meat samples based on ELISA.

Sample	Spiked concentration (ng/g)	Intra-assay (n = 3)		Inter-assay (n = 3)
		Recovery (%)	CV (%)	Recovery (%)	CV (%)
	0.2	93.4	14.5	93.0	13.1
Pork	0.5	98.5	6.4	101.4	13.2
	1	89.9	3.7	96.3	1.4
	2	81.9	3.8	119.8	3.1
	0.2	101.1	23.0	103.5	22.5
Chicken	0.5	96.8	1.6	105.3	15.3
	1	93.4	8.7	118.4	17.6
	2	82.0	3.4	118.7	1.2
	0.2	110.9	22.5	91.8	15.2
Fish	0.5	105.7	7.4	97.4	6.6
	1	98.2	3.3	101.9	4.9
	2	99.8	2.0	101.2	4.0
	0.2	95.4	20.8	108.7	17.5
Shrimp	0.5	95.7	4.1	90.4	10.4
	1	79.9	1.8	83.5	4.0
	2	89.0	8.8	101.8	11.1
	0.2	99.2	16.8	102.9	19.0
Pork liver	0.5	112.5	7.8	93.9	21.5
	1	102.8	0.9	102.7	14.5
	2	94.1	2.5	110.0	3.7
	0.2	109.8	4.0	92.2	19.7
Chicken liver	0.5	107.0	1.0	100.8	13.0
	1	100.1	0.3	109.8	8.3
	2	94.8	4.6	115.4	5.3

Figure 4. TEM picture of 20 nm GNPs.

Figure 5. Typical photo image of detection of AOZ in fish tissue by the strip sensor.

Figure 6. The standard inhibition curve for the AOZ strip sensor.

Table 2. The specificity of the strip sensor.

Compound	Structures	Cross-reactivity (%)	Compound	Structures	Cross-reactivity (%)
Furazolidone		<0.1	AOZ		100
Furantoin		<0.1	AHD		<0.1
Furacilin		<0.1	SEM		<0.1
Furaltadone		<0.1	AMOZ		<0.1
2-NBA		<0.1

Table 3. Recovery test of AOZ in fish samples by the strip sensor.

Sample	Fortified SEM concentration (ng/g)	Intra-assay (n = 3)		Inter-assay (n = 3)
		Recovery (%)	CV (%)	Recovery (%)	CV (%)
Fish	0.02	97.3	4.2	98.2	5.6
	0.05	103.9	4.5	101.9	7.3
	0.1	107.5	6.7	115.5	4.9
	0.2	100.8	3.7	104.8	5.5