Devices, systems and methods for loading samples

1. A system configured to accelerate viscous sample flow into a flow cell, the system comprising:

a sample introduction device configured to provide a positive pressure;

a flow cell fluidically coupled to the sample introduction device and configured to receive sample under the positive pressure from the sample introduction device through a fluid inlet of the flow cell;

a timing fluid line between the sample introduction device and the fluid inlet of the flow cell, the timing fluid line sized and arranged to provide a reference sample from the sample introduction device to the flow cell at a reference time;

a sensor fluidically coupled to the timing fluid line and at the fluid inlet of the flow cell, the sensor configured to determine a time of arrival of the sample;

a valve fluidically coupled to the flow cell at an outlet of the flow cell; and

a pressure device fluidically coupled to the valve downstream of the valve, the pressure device configured to provide a negative pressure to the flow cell when the valve is in a second state to accelerate flow of the sample into the flow cell and configured to be fluidically decoupled from the flow cell when the valve is in a first state to permit sample to flow into the flow cell under the positive pressure provided by the sample introduction device.

2. The system of claim 1 , in which the pressure device comprises a pressure chamber configured to provide a negative pressure to the flow cell when the valve is in the second state and fluidically decoupled from the cell when the valve is in the first state.

3. The system of claim 2 , in which the pressure device further comprises a pump configured to provide the negative pressure in the pressure chamber.

4. The system of claim 1 , further comprising a processor electrically coupled to the valve and the sensor and configured to switch the state of the valve between the first state and the second state based on a determined fill time of the sample.

5. The system of claim 4 , in which the processor is configured to switch the valve from the first state to the second state if the determined fill time exceeds a threshold value.

6. The system of claim 4 , in which the processor is configured to maintain the valve in the first state if the determined fill time is below a threshold value to permit sample to flow into the flow cell only under the positive pressure provided from the sample introduction device.

7. The system of claim 1 , further comprising a detector configured to detect sample in the flow cell.

8. The system of claim 1 , further comprising a reservoir comprising a cleaning fluid, in which the reservoir is fluidically coupled to the flow cell.

9. The system of claim 6 , in which the processor is configured to determine the fill time for the sample using Equation [2]

T =( C 1 +kx−C 2 x 2 +C 3 P+C 4 xP )× z+x   [2]

where C 1 , C 2 , C 3 and C 4 are constants determined empirically from a graph of fill times versus reference times, k is a constant, x is a reference time, P is a pressure device pressure in mbar before a dispense operation is initiated and z is a fill factor.

10. The system of claim 1 , in which the valve is configured as a 3-way solenoid valve.

11. The system of claim 1 , in which the sensor comprises an ultrasonic sensor.

12. A system comprising a flow cell fluidically coupled to a valve downstream of the flow cell and to a pressure device downstream of the valve, the flow cell fluidically coupled to the pressure device when the valve is in a second state to accelerate sample into an inlet of the flow cell, in which the flow cell is fluidically decoupled from the pressure device when the valve is in a first state to permit sample to flow into the flow cell under positive pressure without acceleration of the sample into the flow cell, a sensor positioned at the inlet of the flow cell and configured to determine a time of arrival of the sample at the sensor, a processor electrically coupled to the sensor and configured to determine if the valve should be switched from the first state to the second state using a reference time and a time of arrival of the sample at the sensor, and a fluid flow line fluidically coupled to the inlet of the flow cell, in which the fluid flow line is sized and arranged to provide a reference sample to the flow cell at a reference time.

13. The system of claim 12 , in which the pressure device comprises a pressure chamber fluidically coupled to the flow cell when the valve is in the second state and fluidically decoupled from the flow cell when the valve is in the first state.

14. The system of claim 13 , in which the pressure device further comprises a pump configured to provide the negative pressure in the pressure chamber.

15. The system of claim 12 , in which the processor is configured to determine a fill time for the sample using Equation [2]

T =( C 1 +kx−C 2 x 2 +C 3 P+C 4 xP )× z+x   [2]

where C 1 , C 2 , C 3 and C 4 are constants determined empirically from a graph of fill times versus reference times, k is a constant, x is a reference time, P is a pressure device pressure in mbar before a dispense operation is initiated and z is a fill factor.

16. The system of claim 15 , in which the processor is configured to switch the valve from the first state to the second state if the determined fill time exceeds a threshold value.

17. The system of claim 15 , in which the processor is configured to maintain the valve in the first state if the determined fill time is below a threshold value.

18. The system of claim 12 , further comprising a detector configured to detect sample in the flow cell.

19. The system of claim 12 , further comprising a reservoir comprising a cleaning fluid, in which the reservoir is fluidically coupled to the flow cell.

20. The system of claim 12 , in which the valve is configured as a 3-way solenoid valve.

21. The system of claim 12 , in which the sensor comprises an ultrasonic sensor.