Figure 7
Examination for cross-contamination in 5.5 cm cotton-based diagnosis with 0.3 cm test pad for BSA, nitrite, pH and urobilinogen assays in a clinical urine system.
The total diagnosis procedure was almost the same as the protocol shown in Figure 3. Briefly, we diluted the purified nitrite (0.3 mM), BSA (3.75 μM), hydrochloric acid (pH 6.8 to 4.3) and urobilinogen (25 mg/L) using clinical urine. After data readout (using a desktop scanner to scan the reacting test pad and turning the colorimetric output signal into a grayscale value to analyze the color intensity via the graphics processing software, ImageJ), we obtained the sensitivity to generate an Orginpro 8 histogram. The above histogram illustrates the calibration plot for the mean intensity (I) of the colorimetric result by reagent compound (BSA, urobilinogen and nitrite assays) reaction in the cotton-based diagnostic assay versus the amount of the substrate (BSA, urobilinogen and nitrite) absorbed to each test pad. And pH assays results could be directly observed by the naked eye. Each value is the mean of five replicates (samples number N = 5) and the error bars represent the deviations of the measurements.
