I am using hplc CAD and nitrogen generator. It suddenly aborted my sample run and reflected the message that the total flow is low (it was 0.2). We tried possible troubleshooting listed on the manual but couldnt help. When the engineer came, he found that there is some white powder in the N2 gas inlet to the nebulizer. We dont know what could have caused that and the chamber was sonicated with water and the flow rate was 2.40 and then 1.4, which is fine. I run my samples for two days and on the third day my sample runs were aborted again. This time the screen showed the message that flow ratio is high (1.30). Now I am stuck again. First it was the total flow and now it is the flow ratio, can anyone help or advise?