Veo Observer Plus Instruções de Operação descarregar pdf (Página 73)

Charged Aerosol Detectors

Corona Veo and Corona Veo RS

Operating Instructions Page 65

5.6 Optimizing the Detector Performance

The performance of the detector can be optimized by careful selection of key operating

parameters. The table summarizes these parameters, indicates the performance

characteristics affected, and offers guidelines for selecting the parameters.

Operating Parameter Performance characteristics affected Selection

guidelines

Filter Constant

Sensitivity, baseline noise see page 66

Evaporation Temperature

Baseline noise, background current see page 66

Gas Flow Modes

see page 67

Power Function Value

Linear range see page 68

Baseline Noise

Sensitivity, reproducibility see page 68

Data Collection Rate

Peak resolution, disk space, possibly baseline noise see page 69

5.6.1 General Guidelines

• Make sure that the HPLC column is stable (in flow and temperature) and at the pH of

your mobile phase. Use ‘low-bleed’ columns. Do not use a column that has been used

with non-volatile mobile phases.

• When the mobile phase is stored over a period of time, high background current may be

observed. Replace old mobile phase with freshly prepared mobile phase.

• When you use the detector for the analysis of complex biological samples, proper sample

preparation is especially important.

• Flush new analytical columns to waste for several hours before you connect them to the

system. Use a dedicated column for each specific analysis to avoid cross-contamination

of the column.

• To fully utilize the capabilities of the flow connections within a UHPLC system,

particularly when you use columns with smaller internal diameters, minimize dead

volumes before the detector. This is a commonly overlooked but important cause of band

broadening. Use capillaries with a small internal diameter of the shortest length possible.

Tip: When you perform a gradient, it is recommended to perform blank injections

with the desired LC method gradient profile prior to analysis. This column

"pre-conditioning" will improve the performance of both the analytical HPLC

column and the detector.

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