Optical flow cell apparatus and method for reducing deflection of sample chamber

A method for spectroscopic determination of an analyte in a body fluid sample, the method comprising:

• providing a sample cell having a sample path extending between a first plate member and an opposing second plate member, wherein the sample path is adapted for communicating the body fluid sample from a fluid inlet path through a sample chamber between the first plate member and the second plate member to a fluid outlet path;
• providing one or more spring members between the first plate member and the second plate member, wherein the spring members apply a spring force configured to separate the first plate member from the second plate member;
• moving the first plate member along a normal axis of the first plate and the second plate to a closed configuration by applying a compressive force that overcomes the spring force and urges an abutment surface of the first plate member against an abutment surface of the second plate member, wherein in the closed configuration a predetermined optical path length is provided through the sample chamber for conducting optical measurements;
• and
• preventing the first plate member from flexing over the sample chamber while applying the compressive force by applying the compressive force to an area of the first plate member that extends over the sample chamber.

A sample cell apparatus for use in spectroscopic determination of an analyte in a body fluid sample, the sample cell apparatus comprising:

• a first plate member made from an optically clear material;
• a second plate member made from an optically clear material and opposing the first plate member;
• a first surface of the first plate member facing the second plate member, the first surface comprising
• a first well portion,
• a first seal channel portion adjacent to the first well portion, and
• a first abutment surface outside of the first well portion and outside of the first seal channel portion;
• and
• a second surface of the second plate member facing the first plate member, the second surface comprising
• a second well portion aligned with the first well portion to form a sample chamber,
• a second seal channel portion aligned with the first seal channel portion and adjacent to the second well portion;
• a second abutment surface outside of the second well portion and outside of the second seal channel portion and aligned with the first abutment surface, wherein the first well portion has a fixed depth relative to the first abutment surface and wherein the second well portion has a fixed depth relative to the second abutment surface;
• one or more spring members configured between the first plate member and the second plate member and configured to urge the first plate member away from the second plate member;
• a fluid inlet path extending through the first plate member or the second plate member into the sample chamber;
• a fluid outlet path extending through the first plate member or the second plate member into the sample chamber;
• an actuator member configured to controllably overcome the at least one spring member and to urge the first plate member against the second plate member by a displacement defined by abutment between the first abutment surface and the second abutment surface;
• and
• a vent path extending through the first plate member and into the first seal channel portion.

A method for spectroscopic determination of an analyte in a body fluid sample, the method comprising:

• providing a sample cell having a sample path extending between a first plate member and an opposing second plate member, wherein the sample path is adapted for communicating the body fluid sample from a fluid inlet path through a sample chamber between the first plate member and the second plate member to a fluid outlet path;
• providing one or more spring members between the first plate member and the second plate member, wherein the spring members apply a spring force configured to separate the first plate member from the second plate member;
• moving the first plate member along a normal axis of the first plate and the second plate to a closed configuration by applying a compressive force that overcomes the spring force and urges an abutment surface of the first plate member against an abutment surface of the second plate member, wherein in the closed configuration a predetermined optical path length is provided through the sample chamber for conducting optical measurements;
• providing a floating seal member in a seal channel surrounding the sample chamber;
• and
• preventing the first plate member from flexing over the sample chamber while applying the compressive force by allowing fluid to vent through a vent port in the seal channel.

A sample cell apparatus for use in spectroscopic determination of an analyte in a body fluid sample, the sample cell apparatus comprising:

• a first plate member made from an optically clear material;
• a second plate member made from an optically clear material and opposing the first plate member;
• a first surface of the first plate member facing the second plate member, the first surface comprising
• a first well portion,
• a first seal channel portion adjacent to the first well portion, and
• a first abutment surface outside of the first well portion and outside of the first seal channel portion;
• and
• a second surface of the second plate member facing the first plate member, the second surface comprising
• a second well portion aligned with the first well portion to form a sample chamber,
• a second seal channel portion aligned with the first seal channel portion and adjacent to the second well portion;
• a second abutment surface outside of the second well portion and outside of the second seal channel portion and aligned with the first abutment surface, wherein the first well portion has a fixed depth relative to the first abutment surface and wherein the second well portion has a fixed depth relative to the second abutment surface;
• one or more spring members configured between the first plate member and the second plate member and configured to urge the first plate member away from the second plate member;
• a fluid inlet path extending through the first plate member or the second plate member into the sample chamber;
• a fluid outlet path extending through the first plate member or the second plate member into the sample chamber;
• an actuator member configured to controllably overcome the at least one spring member and to urge the first plate member against the second plate member by a displacement defined by abutment between the first abutment surface and the second abutment surface;
• and
• a foot portion of the actuator member overlapping the sample chamber and configured to urge the first plate member against the second plate member while preventing flexing of the first plate member over sample chamber;
• and
• a vent path extending through the first plate member and into the first seal channel portion.

A method for spectroscopic determination of an analyte in a body fluid sample, the method comprising:

• providing a sample cell having a sample path extending between a first plate member and an opposing second plate member, wherein the sample path is adapted for communicating the body fluid sample from a fluid inlet path through a sample chamber between the first plate member and the second plate member to a fluid outlet path;
• providing one or more spring members between the first plate member and the second plate member, wherein the spring members apply a spring force configured to separate the first plate member from the second plate member;
• moving the first plate member along a normal axis of the first plate and the second plate to a closed configuration by applying a compressive force that overcomes the spring force and urges an abutment surface of the first plate member against an abutment surface of the second plate member, wherein in the closed configuration a predetermined optical path length is provided through the sample chamber for conducting optical measurements;
• providing a floating seal member in a seal channel surrounding the sample chamber;
• and
• preventing the first plate member from flexing over the sample chamber while applying the compressive force by allowing a fluid to vent through a vent port in the seal channel and by applying the compressive force to an area of the first plate member that extends over the sample chamber.