A system for analyzing samples comprising: a device for gripping vessels, comprising: a stationary mount, an elongate support having a longitudinal axis, coupled to the mount in a manner to be rotatable relative to the mount around the longitudinal axis, a rotating mechanism, adapted for rotating the support, a gripper, coupled to the support in a manner to be translatable relative to the support along the longitudinal axis, wherein the gripper is provided with gripping jaws (15, 15') for gripping a vessel, a translating mechanism, adapted for translating the gripper, a first actuator for driving the rotating mechanism and a second actuator for driving the translating mechanism, at least two reference elements (16, 17, 17'), fixed to the mount in at least two different stop positions (38, 39, 39'), wherein the gripping jaws (15, 15') are passively biasable towards each other for holding a vessel at positions other than the at least two stop positions (38, 39, 39') and wherein the gripping jaws (15, 15') are actively biasable away from each other by pushing the gripper against a reference element (16, 17, 17') in one of the stop positions (38, 39, 39'), and wherein the gripper comprises: a gripper head, coupled to the support in a manner to be translatable with respect to the support along the longitudinal axis, a gripper base provided with the gripping jaws (15, 15'), with the gripper head being coupled to the gripper base in a manner to be movable relative to the gripper base against the resilient force of at least one resilient member (20, 20') by pushing the gripper base against a reference element (16, 17, 17') in a stop position (38, 39, 39'), wherein the gripping jaws (15, 15') are coupled to the gripper head in a manner to be moved away from each other by pushing the gripper base against a reference element (16, 17, 17') and to be moved towards each other in positions other than the stop positions (38, 39, 39'), and wherein the gripper head is coupled to the gripper base in a manner to be movable relative to the gripper base with a component of movement perpendicular to the longitudinal axis of the support. a stationary mount, an elongate support having a longitudinal axis, coupled to the mount in a manner to be rotatable relative to the mount around the longitudinal axis, a rotating mechanism, adapted for rotating the support, a gripper, coupled to the support in a manner to be translatable relative to the support along the longitudinal axis, wherein the gripper is provided with gripping jaws (15, 15') for gripping a vessel, a translating mechanism, adapted for translating the gripper, a first actuator for driving the rotating mechanism and a second actuator for driving the translating mechanism, at least two reference elements (16, 17, 17'), fixed to the mount in at least two different stop positions (38, 39, 39'), wherein the gripping jaws (15, 15') are passively biasable towards each other for holding a vessel at positions other than the at least two stop positions (38, 39, 39') and wherein the gripping jaws (15, 15') are actively biasable away from each other by pushing the gripper against a reference element (16, 17, 17') in one of the stop positions (38, 39, 39'), and wherein the gripper comprises: a gripper head, coupled to the support in a manner to be translatable with respect to the support along the longitudinal axis, a gripper base provided with the gripping jaws (15, 15'), with the gripper head being coupled to the gripper base in a manner to be movable relative to the gripper base against the resilient force of at least one resilient member (20, 20') by pushing the gripper base against a reference element (16, 17, 17') in a stop position (38, 39, 39'), wherein the gripping jaws (15, 15') are coupled to the gripper head in a manner to be moved away from each other by pushing the gripper base against a reference element (16, 17, 17') and to be moved towards each other in positions other than the stop positions (38, 39, 39'), and wherein the gripper head is coupled to the gripper base in a manner to be movable relative to the gripper base with a component of movement perpendicular to the longitudinal axis of the support. a gripper head, coupled to the support in a manner to be translatable with respect to the support along the longitudinal axis, a gripper base provided with the gripping jaws (15, 15'), with the gripper head being coupled to the gripper base in a manner to be movable relative to the gripper base against the resilient force of at least one resilient member (20, 20') by pushing the gripper base against a reference element (16, 17, 17') in a stop position (38, 39, 39'), wherein the gripping jaws (15, 15') are coupled to the gripper head in a manner to be moved away from each other by pushing the gripper base against a reference element (16, 17, 17') and to be moved towards each other in positions other than the stop positions (38, 39, 39'), and wherein the gripper head is coupled to the gripper base in a manner to be movable relative to the gripper base with a component of movement perpendicular to the longitudinal axis of the support.