A micro fluidic detection device for examining a liquid sample, the device comprising an inlet having a first longitudinal axis; an outlet having a second longitudinal axis; a detection cell which comprises walls defining a conduit which is in fluid connection with the inlet and the outlet, and has a third longitudinal axis, the third longitudinal axis being at an angle to the first longitudinal axis and at an angle to the second longitudinal axis; a first junction which lies between the inlet and the detection cell; and a second junction which lies between the detection cell and the outlet; whereby a liquid sample can flow along a flow path successively through the inlet, the first junction, the detection cell, the second junction and the outlet; wherein the first junction includes (i) first junction walls, and (ii) a first optical fiber having a portion located in the first junction which, with the first junction wall, defines a first passageway of substantially annular cross-section through which the liquid sample flows as it flows from the inlet to the detection cell; wherein the second junction includes (i) second junction walls, and (ii) a second optical fiber having a portion located in the second junction which, with the second junction walls, defines a second passageway of substantially annular cross-section through which the liquid sample flows as it flows from the detection cell to the outlet; wherein the outer surfaces of each of the first and second optical fibers (28, 32) form a cylinder having a first substantially constant diameter; wherein the first junction walls form a cylindrical shell which has a second substantially constant diameter which is larger than the first diameter, and with the outer surfaces of the first optical fiber, defines a substantially annular region; wherein the second junction walls form a cylindrical shell which has the second substantially constant diameter, and with the outer surfaces of the second optical fiber, defines a substantially annular region; wherein the walls of the detection cell form a cylindrical shell having the second substantially constant diameter; and wherein each of the substantially annular first and second passageways has a length which is 1-10 times the first diameter; characterized in that the device comprises a substantially monolithic body composed of ceramics material, the body including the inlet, the outlet, the detection cell forming the conduit, the first and second junctions (22, 24), and extensions (222, 242) of the first and second junctions for receiving the first and second optical fibers (28, 32); and the inner surface of the conduit is composed of said ceramic material and is exposed to the fluid flowing along said flow path. (i) first junction walls, and (ii) a first optical fiber having a portion located in the first junction which, with the first junction wall, defines a first passageway of substantially annular cross-section through which the liquid sample flows as it flows from the inlet to the detection cell; (i) second junction walls, and (ii) a second optical fiber having a portion located in the second junction which, with the second junction walls, defines a second passageway of substantially annular cross-section through which the liquid sample flows as it flows from the detection cell to the outlet;