A "hand-held" polarimeter for on-site chiral drug measurement and chemical reaction monitoring.

A polarimeter is a common but critical instrument for measuring the optical rotation of chiral compounds, ranging from the pharmaceutical to chemical industry, or even employed in monitoring chemical reactions for research purposes. Developing a portable polarimeter helps to transfer the measurements from the laboratory to on-site detection. Herein, we design a new portable polarimeter with a "hand-held" scale. Technically, we innovatively adopted a rotary potentiometer coupled with a high-precision voltmeter to signify the angle changes after polarized light travels through the chiral compound solution. Compared with the commercial disc polarimeter that uses a dial to measure the optical rotation, such a design shows superiority in being easy to read. This "hand-held" polarimeter meets the high demand for on-site detection on the premise of low cost. Bland-Altman analysis results showed consistency between our device's optical rotation detection method and the commercial disc polarimeter. The "hand-held" polarimeter can measure the optical rotation of a chiral drug and be applicable to monitor the progress of a chemical reaction. As such, this "hand-held" polarimeter shows great potential to assist scientists in scientific research, or for on-site measurement with high portability.