Broadly available imaging devices enable high-quality low-cost photometry

Area of Science:

• Analytical Chemistry
• Biotechnology
• Consumer Electronics Applications

Background:

• Microplate spectrophotometers are essential for parallel absorbance measurements in central laboratories.
• High cost and resource requirements limit the accessibility of these instruments in many settings.

Purpose of the Study:

• To demonstrate low-cost alternatives to expensive microplate spectrophotometers for absorbance measurements.
• To validate the use of consumer electronic devices for biochemical analyses in resource-limited environments.

Main Methods:

• Developed two photometer prototypes: a flatbed scanner and a cell phone camera-based device.
• Utilized RGB imaging sensors to measure light transmittance through microtiter plate samples.
• Calculated RGB-resolved absorbance from pixel color values, correlating it with absorbance spectra.

Main Results:

• Established a theoretical relationship between sample absorbance spectra and RGB-resolved absorbance.
• Demonstrated linearity and precision in measurements of dyes and chromogenic assay products.
• Validated the reliability of low-cost photometers across various chemical and biochemical analyses.

Conclusions:

• Inexpensive consumer electronics can reliably replace costly spectrophotometers for absorbance measurements.
• This technology facilitates parallel, low-cost sample analysis, expanding testing capabilities in resource-limited areas.
• Enables crucial diagnostic and analytical testing where advanced laboratory infrastructure is unavailable.