Detector problems ?
Posted: Sun Feb 25, 2018 7:52 pm
Hi,
I have been analyzing water samples for some time with Metrohm Ic. Our column is Metrosep Asupp 5-250, size 4,6*250 mm and particle size is 5,0 µm.
Eluent: 1.0 mmol/L NaHCO3 / 3,2 mmol/L Na2CO3.
Flow: 0,70 mL/min
H2SO4: 0,1 M
When I start Ic and start flushing suppressor channels by pressing the "step" button, conductivity rises to its maximum level. The level has been adjusted to 1341 µs/cm*sec by sofware. This rise also occurs when injecting standards or samples.
Conductivity stays up for ten seconds and then descend rapidly to 16 -18 µs/cm*sec. Sulfate analyzes have been reliable, but there are major problems with nitrate.
We send one sample to another laboratory, and result for nitrate was 0,7 ppm.
Our result was 5 ppm.
The amount of sulfate was moderate 10ppm.
I have been analyzing water samples for some time with Metrohm Ic. Our column is Metrosep Asupp 5-250, size 4,6*250 mm and particle size is 5,0 µm.
Eluent: 1.0 mmol/L NaHCO3 / 3,2 mmol/L Na2CO3.
Flow: 0,70 mL/min
H2SO4: 0,1 M
When I start Ic and start flushing suppressor channels by pressing the "step" button, conductivity rises to its maximum level. The level has been adjusted to 1341 µs/cm*sec by sofware. This rise also occurs when injecting standards or samples.
Conductivity stays up for ten seconds and then descend rapidly to 16 -18 µs/cm*sec. Sulfate analyzes have been reliable, but there are major problems with nitrate.
We send one sample to another laboratory, and result for nitrate was 0,7 ppm.
Our result was 5 ppm.
The amount of sulfate was moderate 10ppm.