Abstract: The invention relates to a device and method for measuring the concentration, size and zeta potential of nanoparticles in liquids in scattered light mode and fluorescence mode, comprising the following features: a) a sample (28) is irradiated from above by a laser (1) via a beamsplitter (14) and an adjustable-focus liquid lens (9), and the reflected beam of light is deflected by the same beamsplitter (14) and a further liquid lens (8) onto a detector (5), and analysed; b) to observe the fluorescent light, a fluorescence filter (19) is connected in the convergent beam path between the liquid lens (8) and the detector (5), to increase the distance between the scattered light plane (31) and the fluorescence plane (30); and c) to control the measurement process, a particle tracking program, an optical control unit (15) and a display (2) with a touch screen are used.

Abstract: The invention relates to a device and method for measuring the concentration, size and zeta potential of nanoparticles in liquids in scattered light mode and fluorescence mode, comprising the following features: a) a sample (28) is irradiated from above by a laser (1) via a beamsplitter (14) and an adjustable-focus liquid lens (9), and the reflected beam of light is deflected by the same beamsplitter (14) and a further liquid lens (8) onto a detector (5), and analysed; b) to observe the fluorescent light, a fluorescence filter (19) is connected in the convergent beam path between the liquid lens (8) and the detector (5), to increase the distance between the scattered light plane (31) and the fluorescence plane (30); and c) to control the measurement process, a particle tracking program, an optical control unit (15) and a display (2) with a touch screen are used.

Abstract: A method and device for optically detecting particles, including: (a) a cell wall of rectangular cross-section is fitted on a longitudinal surface and adjoining transverse surface with an L-shaped heating and cooling element; (b) the center of the transverse surface of the cell wall opposite the transverse surface which forms the support of the cell wall is irradiated by an irradiation device and is observed at right angles to the optical axis of the irradiation device; (c) the focus of the irradiation device and the observation device can be moved by a motor to any point in the three-dimensional inner region defined by the cell wall; (d) the surface of the cell wall opposite the optical glass window through which the radiation from the irradiation device enters comprises another optical glass window; (e) the temperature of the surface of the cell wall is monitored by two thermistors.