Simple and sensitive detection of triazophos pesticide by using quantum dots nanobeads based on immunoassay

Figures & data

Scheme 1. (A) Schematic illustration of the QDs-mAb probes preparation. (B) Schematic illustration of the established competitive fluorescence immunoassay for pesticide detection.

Figure 1. Characterisation of a series amount of molar ratio between mAb and QDs.

Figure 2. Characterisation of QDs-mAb probes. (A) TEM micrographs of QDs, (B) TEM micrographs of QDs-mAb. Normalised fluorescent spectra (C) of QDs (upper line) and QDs-mAb (lower line). The UV–Vis spectrum (D) of bare mAb (upper line), QDs modified with antibodies (middle line), and bare QDs (lower line).

Table 1. Optimized working concentrations of QDs-mAb and OVA-hapten.

Antigen (mg L^–1)	IC50 (μg L^–1)	IC10 (ng L^–1)	Fmax/IC50
1.25	0.46	0.508	1392.8
0.63	0.37	0.688	1348.6
0.31	4.51	3.18	152.4
0.16	10.7	1.28	34.6

Figure 3. The standard curve of triazophos; the linear range was 0.01–25 μg L⁻¹; three replicates were performed.

Table 2. Recoveries and relative standard deviations (RSDs) of the fluorescence immunoassay and LC-MS/MS.

Sample	Spiking concentration (μg kg^–1)	Recoveries/RSD (%)
		This method	LC-MS/MS
Water	5.0	82.6/13.1	97.9/1.1
	10.0	95.3/15.2	92.1/0.5
	50.0	87.6/11.1	96.0/0.2
Apple	5.0	88.7/8.4	89.0/1.3
	10.0	87.5/7.1	104.1/0.8
	50.0	96.6/8.4	97.3/1.0
Pear	5.0	91.3/7.7	82.3/1.6
	10.0	92.1/6.4	87.9/1.2
	50.0	92.3/9.9	87/0.7
Cucumber	5.0	85.9/5.8	105.2/1.9
	10.0	84.7/10	93.6/1.3
	50.0	88.5/6.9	107.1/0.6
Rice	5.0 10.0 50.0	87.0/5.0 90.5/10.9 90.2/6.5	82.4/0.7 82.1/1.1 84/0.6

Table 3. Comparison of various fluorescence immunoassays.

Method	Liner range (ng mL^−1)	LOD (ng mL^−1)	Reference
CdSe/ZnS (core/shell) quantum dots (QDs) and anti-benzothiostrobin antibody (IgG) based fluorescence lateral flow test strip (FLFTS)	25–150	25	Wu et al. (2019)
THBu-EDF and anti-triazophos mAb were used to construct the fluorescence polarization immunoassay (FPIA) method for triazophos detection	1.25–10.48	0.29	Liu et al., (2016)
Dual-label time-resolved fluorescence immunoassay for the simultaneous determination of carcinoembryonic antigen and squamous cell carcinoma antigen	3.24–543.67	1.15	Mao et al. (2018)
	2.47–96.58	0.54
HDS–ZnO–APS microarray was investigated by the sandwiched fluorometric immunoassays of human IgG	0.01–10	5 × 10^-3	Li et al. (2015)
Plate-based FLISA and nitrocellulose membrane-based flow-through FLISA were developed and applied to quantitative and qualitative detection of morphine	0.32–1000	0.27	Zhang et al. (2017)
CdSe/ZnS quantum dots conjugate mAb FLISA for the detection of triazophos	0.01–25	0.508 × 10^-3	This work

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