Portable photo absorption sensors test a solution for multiple parameters rapidly and simultaneously, saving valuable time in the lab. The sensor measures fluorescence intensity in order to provide measurements of sample concentration and to graph the standard calibration curve; it can quickly detect substances such as protein, heavy metals, endocrine disruptors, and DNA. Rather than pipetting the solution into a separate container, a PCR tube is inserted directly into the handheld device, which saves time while reducing contamination and sample loss. Portable photo absorption sensors can be used in chemistry/biochemistry, medical, and environmental industries.