The methyl parathion barcode-formatted assay was scanned
using a free barcode scanning app, QuickMark;24 the barcode
is scanned and the result is automatically shown. The image
of the working area and the result can be captured by the
phone’s screen capture function with or without the flash
enabled and saved as a PNG image. The flash acts as a stable
light source for scanning the barcode with the app. The image
is then transferred to a computer running Adobe Photoshop
CS6 to analyze the image by reading the color (yellow intensity)
information within the detection area. The average
yellow intensity and the associated uncertainties in each detection
region were obtained from at least three replicate
measurements.