Optical measuring apparatus and method for the analysis of samples contained in liquid drops

An optical measurement apparatus (1) configured for the analysis of samples contained in liquid drops (2) that are provided by a liquid handling system (3) which comprises at least one liquid handling tip (4) with a liquid handling axis (5) and with a liquid handling orifice (6) at a distal end (7) of the liquid handling tip (4), the liquid handling axis (5) extending inside the liquid handling tip (4) and penetrating the liquid handling orifice (6);

• the optical measurement apparatus (1) comprising a light source (8) configured for providing irradiation light (9) for irradiating a liquid drop (2) of a liquid sample (30);
• a detector (10) configured for measuring sample light (11) arriving from said liquid drop (2) and for providing measurement signals (12) that represent the measured sample light (11);
• an optics system (43) with first optical elements (18) for transmitting the irradiation light (9), an a processor (13) connected to the detector (10) and configured to accept and process the measurement signals (12) provided by the detector (10),
• wherein the light source (8) and the liquid drop (2) defining a first optical axis (14) of the first optical elements (18) of the optics system (43) that extends essentially perpendicular to the liquid handling axis (5), the liquid drop (2) provided by the liquid handling system (3) being suspended at the liquid handling orifice (6) of the liquid handling tip (4) in a position where the liquid drop (2) is penetrated by the first optical axis (14),
• wherein the liquid drop (2) is physically separated from the optics system (43) of the optical measuring apparatus (1) and is physically touched only by the liquid handling tip (4) of the liquid handling system (3) and the liquid sample (30) inside the liquid handling tip (4), the light source (8) with the first optical elements (18) being thus separated from the liquid drop (2) by a first air space (15) and the detector (10) being thus separated from the liquid drop (2) by a second air space (16),
• and wherein the optical measuring apparatus (1) comprises a robot arm (45) that is configured to be moved in one or more directions of a coordinate system and for adapting the position of the liquid drop (2) with respect to at least one optical element (18) of the optics system (43).

An optical measuring method of analyzing samples contained in liquid drops (2) that are provided by liquid handling systems (3),

• wherein the method comprises the steps of:
• (a) providing a liquid handling system (3) which comprises at least one liquid handling tip (4) with a liquid handling axis (5) and with a liquid handling orifice (6) at a distal end (7) of the liquid handling tip (4), the liquid handling axis (5) extending inside the liquid handling tip (4) and penetrating the liquid handling orifice (6);
• the liquid handling system (3) comprising a pump (39) that is controlled by a central processor (44) of the liquid handling system (3), the pump (39) being operatively connected to the liquid handling tip (4) via a pressure line (40);
• (b) providing a liquid drop (2) that is suspended at the liquid handling orifice (6) of the liquid handling tip (4) of the liquid handling system (3) in a position where the liquid drop (2) is penetrated by a first optical axis (14) that extends essentially perpendicular to the liquid handling axis (5);
• (c) providing an optical measuring apparatus (1) that comprises a processor (13), a light source (8), a detector (10), and an optics system (43) with first optical elements (18) for transmitting irradiation light (9) from the light source (8) to the liquid drop (2) and with second optical elements (19) for transmitting sample light (11) from the liquid drop (2) to the detector (10);
• the light source (8) and the liquid drop (2) defining the first optical axis (14) of the first optical elements (18) of the optics system (43);
• a first and second air space (15,16) separating the liquid drop (2) from the light source (8) and detector (10) and their associated first and second optical elements (18,19) that thus do not contact the liquid drop (2);
• (d) irradiating the liquid drop (2) with irradiation light (9) originating from the light source (8);
• (e) measuring sample light (11) arriving at the detector (10) from the liquid drop (2) and providing measurement signals (12) with the detector (10);
• and
• (f) processing with the processor (13) that is operatively connected to the detector (10) the measurement signals (12) provided by the detector (10).