acetamiprid method

[lusi]

Hi Can anyone tell me of a method they used to detect acetamiprid on LC MS (single quad)?
I tried using 1% acetic acid and ACN, but no luck.
Thanks in advanced.

[H.Thomas]

You asked the same question for chlorpyriphos already. But in both cases you did not describe where your problem actually is. What have you tried? FIA, LC? What concentration did you use? What do you mean by "no luck"? Didn't see any mass in Scan-Mode?

Acetamiprid should be detetctable by ESI+, using the ions 223, 225 and 126.

[lusi]

I apologise for the scanty details. When I used LC with a single quadrupole MS detector, I was unable to get a peak to correspond with the weight of the compound (223). In fact it I really did not get any peaks, just what appeared to be alot of noise and spikes maybe.
The injection volume was 5ul of 10ppm acetamiprid.
I used cone voltages of +150 to +15V in ESI and needle voltages of 3 to 5. I used a variety of concentrations from 0 to 100 ACN to 1% Acetic acid in water.
I also used full scan from 190 to 240.
By the way what is FIA?
I used this method even though it was for a triple quad MS because I was unable to find one using a single quad MS.

[lusi]

Tried ACN and DI water alone and the compound was seen with a very nice peak. I guess the buffer actually hindered the detection....

[H.Thomas]

FIA is Flow Injection Analysis, which means that you infuse a standard of your substance directly into the MS (bypassing the HPLC). This can be useful to optimize MS parameters. Some MS have a syringe pump for this purpose.

The acid should not prevent detection, though 1% is quite a lot (I usually take 0.01 to 0.1 %). You might want to check the quality of your HAc.

Methods for a triple quad should also work for a single quad, if you use the precursor ions of the MS/MS-method in SIM.

[lusi]

Thanks H Thomas. This was quite helpful.
I never tried injecting directly to the MS, since I am quite new to the LC.
Thanks so much for the advice.