Rndirk wrote:
For instance, you risk getting into trouble with overloading the column. You're exposing the system to more than what's needed (analytes + matrix). You'll have to retune (?) the lower EM voltage, and again if you want to run a different analysis.
Actually lowering the voltage doesn't always require retuning. If you run an autotune then use a negative relative EM voltage say -100V it will just lower the intensities.
Column overload will present itself as distorted peaks, and as long as you do not see signs of that it will be ok. Detector overloading will present itself as flat top peaks or even negative dips within a peak where the detector shuts down for a scan to prevent damage. Turning up the gain can cause detector overload even when the column is well within its limits. The autotunes also sometimes set the detector voltage higher than needed for certain analyses. Best to run a low calibration standard and adjust the voltage to make for a suitable peak size, then run a high calibration standard to make sure you are not overloading either the column or detector. If the detector overloads with the high standard, then you need to lower the voltage but increase the amount on column of the low standard by lowering the split ratio or increasing the injected volume.
It is a balancing act to get everything right to cover the largest operating range for the instrument, if you need a large range. If you are looking for an analyte that will always be within 10% of a known value, then it is easy to just lower the voltage until you are getting good results as that will help extend the life of the detector.