| Popis: |
Magnetic optical sensor particles (MOSePs) in nanometer scale for pH measurement were synthesized and characterized. The measurement of pH is based on a ratiometric evaluation of the fluorescence of a pH‐sensitive indicator dye (N‐fluorescein‐acrylamide) and a reference dye (a rhodamine derivative) which is not affected by pH. Measurement of pH in aqueous media in the range of pH 5 to 9 is reversibly possible. As the particles can be collected in front of fiber optics with a specially designed separator, signal enhancement is easily achieved. Therefore, a low concentration of MOSePs is sufficient for investigations. Using the here reported MOSePs, the read out of pH is noninvasive, i.e., no dip probe needs to be inserted into the medium. In addition, no further preparation steps are required, pH‐sensitive MOSePs can be simply pipetted into the medium prior to measurement, magnetically collected at the side and read out with a fiber optic device through the glass wall. |
