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- Posts: 3
- Joined: Wed Nov 16, 2022 8:14 pm
- Location: United States of America
I am trying to develop an IC method that has a linear gradient elution from 7mM to 40mM to achieve fluoride, acetate, formate, nitrite, nitrate, sulfate, and phosphate. Currently, two separate isocratic methods are being used to achieve all the peaks. The LOQ for the isocratic runs is 10ppb, but when calibrating the gradient, acetate and formate disappear at that level on the gradient. I have tried a method that stays at 7mM for the first 10 minutes to elute those first 3 peaks before ramping and that didn’t work. Does a gradient elution decrease sensitivity? I’m pretty new to the ion chromatography so this may be an easy fix for someone more well-versed.
Any advice on gradient elution methods or on increasing sensitivity on the IC or any advice in general would be greatly appreciated.
System: Dionex ICS-6000
Column: AS18 4 x 250mm
EGC: EGC KOH 500 RFIC
Suppressor: ADRS 600
Flow rate: 0.8 mL/min
Injection Volume: 100µL