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- Posts: 50
- Joined: Tue Oct 30, 2012 2:26 pm
Hi everyone,
i need to perform a sensitivity test for our triple-quadrupole LC-MS with 5microlitre injection of 200fg/ul reserpine solution (total of 1pg of reserpine).
My issue is, that after calculating in two different ways, i have obtained two very different results. The limit for the test is signal-to-noise of at least 1500:1.
when performing the test manually (manual noise region selection, i selected a 1.5minute interval just before the peak) i obtained a very low signal-to-noise with RMS algorithm (around 250), but when i selected an automated calculation algorithm "repetitive noise" (The software help section says this: "Use a multiple pass algorithm to determine the noise level. The ICIS peak detection algorithm uses this value. In general, this algorithm is more accurate in analyzing the noise than the INCOS Noise algorithm, but it takes longer.") i obtained a value which is within limits(around 1700).
Is it correct to use the algorithm that gives the better results, and do you think this chromatogram has a sensitivity of 1500:1?? Or is it just artificially obtained and not OK from regulatory point of view?
If anyone could please help me with some answers i would gladly send you printscreens of the dilemma, because i cannot attach them to this post.
My email address is lenard21@gmail.com
Thank you
i need to perform a sensitivity test for our triple-quadrupole LC-MS with 5microlitre injection of 200fg/ul reserpine solution (total of 1pg of reserpine).
My issue is, that after calculating in two different ways, i have obtained two very different results. The limit for the test is signal-to-noise of at least 1500:1.
when performing the test manually (manual noise region selection, i selected a 1.5minute interval just before the peak) i obtained a very low signal-to-noise with RMS algorithm (around 250), but when i selected an automated calculation algorithm "repetitive noise" (The software help section says this: "Use a multiple pass algorithm to determine the noise level. The ICIS peak detection algorithm uses this value. In general, this algorithm is more accurate in analyzing the noise than the INCOS Noise algorithm, but it takes longer.") i obtained a value which is within limits(around 1700).
Is it correct to use the algorithm that gives the better results, and do you think this chromatogram has a sensitivity of 1500:1?? Or is it just artificially obtained and not OK from regulatory point of view?
If anyone could please help me with some answers i would gladly send you printscreens of the dilemma, because i cannot attach them to this post.
My email address is lenard21@gmail.com
Thank you
