Figure 1.
Molecular structures of the haptens.
Hapten 1 was used as immunizing hapten and homologous coating hapten, hapten 2 to 12 were used as heterogenous coating hapten candidate. ni: no atom.
Figure 2.
Schematic diagram of ICA test strip and result judgment.
The ICA test strip was composed of the NC membrane, MAb-gold-conjugated pad, sample pad and absorbent pad, which were pasted onto an adhesive plastic backing. Result judgment was based on the color changed on the T and C line zone.
Figure 3.
Each point on the y axis represents the mean D-value of absorbance (528 nm) in two stages (for details, see materials and methods), and the x axis values are the concentration of the mAb (n = 3).
Figure 4.
Each point on the y axis represents the average value for the G/Peak - ROD, and the x axis values are the time after the addition of the working buffers (n = 3).
Figure 5.
A: Concentration range of parathion-methyl standard assayed by the ICA test strip; B: Relative optical density (ROD) curves of parathion-methyl; C: Standard inhibition curves of parathion-methyl; D: The calibration curve from “A”; “B/B0” is binding ratio of antibody/antigen on the test line.
Table 1.
IC50 values and LOD (IC10) of a set of analogs related to parathion-methyl by multi-analyte ICA and ELISA.
Table 2.
Cross-reactivity (CR) of a set of analogs related to parathion-methyl by multi-analyte ICA and ELISA.
Figure 6.
Matrix interference study and correlation of recoveries between the ICA and ELISA.
A: Standard inhibition curves for parathion-methyl in the buffer and different matrices using the multi-analyte ICA, Chinese cabbage and Apple samples were diluted 5-fold, and greengrocery samples were diluted 20-fold; B: Standard inhibition curves for parathion-methyl in the buffer and different matrices using the multi-analyte ELISA, Chinese cabbage, Apple and greengrocery samples were diluted 40-fold; C: The degree of correlation between the multi-analyte ICA and ELISA for analyses of samples spiked with parathion-methyl, parathion, and fenitrothion.
Figure 7.
Matrix interference of greengrocery in ICA test strip.
ICA test strip detection of parathion-methyl with 10-, 20-, 40-fold dilutions of greengrocery matrix interference and buffer. Standard solutions of parathion-methyl at each final concentration of 128, 64, 32, 16, 8, 4, 2 and 0 ng mL-1 (numbers across the top of strips from left to right) were tested.
Table 3.
Recovery studies of samples spiked with parathion-methyl, parathion, and fenitrothion by multi-analyte ICA (n = 4).
Table 4.
Recovery studies of samples spiked with parathion-methyl, parathion, and fenitrothion by multi-analyte ELISA (n = 3).