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 to force sample from the sample introduction device into a flow cell ; the flow cell fluidically coupled to the sample introduction device and configured to receive the forced sample 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 ; a sensor fluidically coupled to the timing fluid line and positioned in the fluid inlet of the flow cell , the sensor configured to determine a time of arrival of the sample at the fluid inlet of the flow cell ; a valve positioned in a fluid line downstream of a fluid outlet of the flow cell and between the flow cell and a pressure device ; the pressure device , said pressure device being fluidically coupled to the flow cell and configured to provide a negative pressure to the flow cell when the valve is in a second state and being fluidically decoupled from the flow cell when the valve is in a first state; a processor electrically coupled to the valve and the sensor and configured to switch the valve between the first state and the second state, wherein the processor is configured to switch the valve from the first state to the second state when the determined time of arrival of the sample exceeds a threshold value to accelerate flow of sample into the flow cell , wherein the processor is configured to maintain the valve in the first state when the determined time of arrival of the sample is below the threshold value to permit sample to flow into the flow cell under positive pressure provided by the sample introduction device . a sample introduction device configured to provide a positive pressure to force sample from the sample introduction device into a flow cell ; the flow cell fluidically coupled to the sample introduction device and configured to receive the forced sample 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 ; a sensor fluidically coupled to the timing fluid line and positioned in the fluid inlet of the flow cell , the sensor configured to determine a time of arrival of the sample at the fluid inlet of the flow cell ; a valve positioned in a fluid line downstream of a fluid outlet of the flow cell and between the flow cell and a pressure device ; the pressure device , said pressure device being fluidically coupled to the flow cell and configured to provide a negative pressure to the flow cell when the valve is in a second state and being fluidically decoupled from the flow cell when the valve is in a first state; a processor electrically coupled to the valve and the sensor and configured to switch the valve between the first state and the second state, wherein the processor is configured to switch the valve from the first state to the second state when the determined time of arrival of the sample exceeds a threshold value to accelerate flow of sample into the flow cell , wherein the processor is configured to maintain the valve in the first state when the determined time of arrival of the sample is below the threshold value to permit sample to flow into the flow cell under positive pressure provided by the sample introduction device . <EOS>