Table D-3 Source-Dependent Parameters (continued)
Parameter
Description
Nebulizer current
Controls the current applied to the corona discharge needle in the APCI
probe. The discharge ionizes solvent molecules, which in turn ionize the
sample molecules. For the APCI probe, the current applied to the corona
discharge needle usually optimizes over a broad range of about 1 µA
to 5 µA, in Positive polarity. To optimize, start at a value of 1 and then
increase to achieve the best signal or signal-to-noise ratio. If, when the
current is increased, no changes in signal are observed, then leave the
current at the lowest setting that provides the best sensitivity, for example,
2 µA.
Ion source voltage Controls the voltage applied to the sprayer in the TurboIonSpray probe,
which ionizes the sample in the ion source. The parameter value depends
on the polarity, and affects the stability of the spray and the sensitivity.
In the Analyst software, this is the
IonSpray Voltage
field.
Interface heater
This parameter is always on for 3200 series systems.
Turns the interface heater on and off. Heating the interface helps maximize
the ion signal and prevents contamination of the ion optics. Unless the
compound the user is analyzing is extremely fragile, we recommend that
the user heat the interface.
Probe Position
The position of the probe can affect the sensitivity of the analysis. For more information on how
to optimize the position of the probe, refer to the section:
.
Solvent Composition
The standard concentration of ammonium formate or ammonium acetate is from 2 mmol/L to
10 mmol/L for positive ions and 2 mmol/L to 50 mmol/L for negative ions. The concentration
of organic acids is 0.1% to 0.5% by volume for the TurboIonSpray probe and 0.1% to 1.0% by
volume for the APCI probe.
Commonly used solvents are:
• Acetonitrile
• Methanol
Source Parameters and Voltages
SCIEX 3200 Systems
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System User Guide
RUO-IDV-05-6475-C
