Can someone please share the information or experience on flushing the anion exchange column from the arsenic speciation kit by ESI? The manufacturer doesn't provide any information about this with the product, nor any info on characteristics of the column, what stationary phase and what functional groups are. Is there possibility of reversing the flow of the eluent without damaging the column?

I suspect that the column is blocked be particulate matter. The kit is connected to ICP-MS equipped with SC-DX FAST system. The analytical sequence is set according to the instructions provided with the kit, 20 µL of sample, 120s of buffer 1 (ca. 2 mmol ammonium phosphate pH=9.7) followed by 660s of buffer 2 (ca. 40 mmol ammonium phosphate pH=8.6). The samples are calibration solutions of As species (As3, As5, MMA, DMA).

I observe problems with nebulization which is interrupted in and irregular manner. For a fraction of second nebulization stops then starts again like something is blocking the flow for a moment, which is also simultaneously visible as the brief brightening and dimming of the plasma. In the chromatogram one can see sudden drop of baseline to the zero followed by peak much higher than the baseline (see attached jpeg). This phenomena occurs more often while aspiring more diluted buffer 1 and after switching to buffer 2 with higher concentration it usually happen less frequently. Sometimes there is no drop, only very sharp and high peak, even when the sample is milliq water. When I run only milliq water, instead of buffers, this occurs very often, every few seconds throughout the analysis which takes over a dozen of minutes. I didn’t yet analyzed any sample besides the calibration solutions in water (max conc. 50 ppb).

There is no reply from manufacturer so maybe anyone of you fellow researchers have any recommendations in this situation?