This file describes an LC/MSD autotuning method that can optimize analysis parameters in both positive and negative ionization modes and create a tuning file that contains optimized parameters.
The document describes a technique for acquiring mass spectrometry information using different acquisition modes within a single sample analysis. It highlights how this approach improves productivity in LC/MS compound screening and simplifies method development by allowing the use of a single, generic method.
Specific examples are provided showing the analysis of sulfonamide antibiotics via electrospray ionization (ESI) and polymer additives via atmospheric pressure chemical ionization (APCI). The text details how alternating positive and negative ionization modes maximizes information from each analysis, confirming molecular weights and detecting fragmentation patterns that might be missed in a single mode.
| System Components | binary pump, vacuum degasser, auto-sampler, thermostatted column compartment with column-switching valve, diode-array detector, and an enhanced LC/MSD |
|---|---|
| Column (Sulfonamides) | 15 × 3 mm Zorbax SB-C18, 3.5 µm |
| Flow Rate (Sulfonamides) | 0.6 ml/min |
| Column Temperature (Sulfonamides) | 40°C |
| Injection Volume (Sulfonamides) | 5 µl |
| Drying Gas Flow (ESI) | 11 l/min |
| Vcap (Positive Mode, ESI) | 3000 V |
| Column Temperature (Polymer Additives) | 50°C |
| Flow Rate (Polymer Additives) | 0.8 ml/min |
The autotune process automatically delivers a tune mix, optimizes parameters in both positive and negative ionization modes, and creates a single tune file for polarity switching.
It allows confirmation of peak molecular weight without increasing analysis time or sample use by capturing ions in both modes simultaneously.