Gold - chemistry, Microfluidic Analytical Techniques, Thymine - chemistry, Colorimetry - methods, Limit of Detection, Mercury - analysis, Metal Nanoparticles - chemistry, Water - analysis, Colorimetry - instrumentation, Rivers, Water Pollutants, Chemical - analysis, Water - chemistry, Paper, Cell Phone, DNA, Single-Stranded, Nanoparticles, Gold, Chemical pro...