Method to calibrate disposable cartridge cuvette thickness in-situ
An analytical system includes a laser disposed to direct light toward a microfluidic feature disposed in a feature layer of a multiple layer test cartridge, a sensor to receive reflections from capping layers disposed about the microfluidic feature in the feature layer, and a controller to determine a depth of the microfluidic feature as a function of the received reflections.
1. A method comprising:
inserting a multiple layer microfluidic test cartridge into an analytical instrument;
without a fluid in a microfluidic feature, measuring a depth of the microfluidic feature in a feature layer in the multiple layer microfluidic test, cartridge via an optical sensor in the analytical instrument;
calibrating the analytical instrument for a volume of the microfluidic feature based on a calibration value determined based on output of the optical sensor;
moving the fluid into the microfluidic feature;
after moving the fluid into the microfluidic feature, determining, at the optical sensor, a second output; and
adjusting, based on the calibration value, a volume of the fluid in the microfluidic feature determined based on the second output.
2. The method of claim 1 wherein the calibration value is determined from a lookup table.
3. The method of claim 1 wherein the measured depth is a depth of cuvette defined in the feature layer of the microfluidic test cartridge.
4. The method of claim 1 wherein measuring the depth of the microfluidic feature comprises mapping angled reflections of laser light from the microfluidic feature onto a photo-detector array.
5. The method of claim 4 wherein the angled reflections comprise reflections from adjacent layers capping the microfluidic feature in the feature layer.
6. The method of claim 5 wherein the angled reflections are matched to determine the depth via application of Snell's law.
7. The method of claim 1 wherein measuring the depth of the microfluidic feature comprises:
sensing reflections of a laser directed orthogonal to the microfluidic feature; and
detecting interference in reflections from the microfluidic feature.
8. The method of claim 7 wherein the reflections comprise reflections from adjacent layers capping the microfluidic feature in the feature layer.
9. (A non-transitory machine-readable medium including instructions that, when executed by a machine, configure the machine to perform operations comprising:
without a fluid in a microfluidic feature, measuring a depth of the microfluidic feature in a feature layer in a multiple layer microfluidic test cartridge via an optical sensor situated on a first side of the microfluidic feature and in an analytical instrument;
calibrating the analytical instrument for a volume of the microfluidic feature based n a calibration value determined based on output of the optical sensor;
moving the fluid into the microfluidic feature;
after moving the fluid into the microfluidic feature, determining, at the optical sensor, a second output; and
adjusting, based on the calibration value, a volume of the fluid in the microfluidic feature determined based on the second output.
10. The non-transitory machine-readable medium of claim 9 , wherein the calibration value is determined from a lookup table.
11. The non-transitory machine-readable medium of claim 9 , wherein the measured depth is a depth of cuvette defined in the feature layer of the microfluidic test cartridge.
12. The non-transitory machine-readable medium of claim 9 , wherein measuring the depth of the microfluidic feature comprises mapping angled reflections of laser light from the microfluidic feature onto a photo-detector array.
13. The non-transitory machine-readable medium of claim 12 , wherein the angled reflections comprise reflections from adjacent layers capping the microfluidic feature in the feature layer.
14. The non-transitory machine-readable medium of claim 13 , wherein the angled reflections are matched to determine the depth via application of Snell's law.
15. The non-transitory machine-readable medium of claim 9 , wherein measuring the depth of the microfluidic feature comprises:
sensing reflections of a laser directed orthogonal to the microfluidic feature; and
detecting interference in reflections from the microfluidic feature.
16. The non-transitory machine-readable medium of claim 15 , wherein the reflections comprise reflections from adjacent layers capping the microfluidic feature in the feature layer.