Table 1.
Dependence of Normalized Intensity for the Peak m/z 369.35 on the Cone Voltage and Additives
|
Cone Voltage, V |
Im/z
369.35/IWE 44:1 |
|||
|
NH4Ac |
NaI |
|||
|
1 mM, % |
100 μM, % |
1 mM, % |
100 μM, % |
|
| 15 | 4.3 | 4.2 | 2.2 | 1.0 |
| 50 | 44.2 | 23.0 | 0.4 | 0.8 |
| 75 | 61.8 | 27.0 | 1.2 | 1.3 |
Mass spectra were acquired at the desolvation temperature of 150°C for meibum sample containing ∼13 μg/mL (∼17 μM). IWE44:1 is the sum of the intensities of sodiated, ammoniated, and protonated peaks of WE 44:1. The normalized intensities for spectra with 10 μM additives are not listed due to the low signal-to-noise ratio, likely resulting from inadequate amount of additive to promote the ionization of lipids in the samples.