Needle seat malfunction on Waters Alliance
Posted: Fri Nov 17, 2006 2:58 pm
Have a constant problem with a couple of the LCs in here. They tend to have a "needle seat malfunction (bottom sensor)" error upon trying to make the first injection. After the first injection, there are no problems after that.
The Waters maintenance guy says that it's a typical occurrance and said to put a dab of solvent on the needle seat. I tried it, and it does work, in terms of enabling the first injection to be made. However, I'm now seeing my precision injections (0.2 ppm solution) increase in area significantly at the beginning of a run, and I'm thinking that there may be a connection.
I'm wondering if a) the drifting response may be from my analyte being diluted in the first injections by the solvent I applied to the seat, and b) if there's a better way to "unbind" the needle.
Is this a simple matter of needing to replace the seat? There's no accumulation of buffer salts.
The Waters maintenance guy says that it's a typical occurrance and said to put a dab of solvent on the needle seat. I tried it, and it does work, in terms of enabling the first injection to be made. However, I'm now seeing my precision injections (0.2 ppm solution) increase in area significantly at the beginning of a run, and I'm thinking that there may be a connection.
I'm wondering if a) the drifting response may be from my analyte being diluted in the first injections by the solvent I applied to the seat, and b) if there's a better way to "unbind" the needle.
Is this a simple matter of needing to replace the seat? There's no accumulation of buffer salts.