Chromatography Forum

Hello, Does anyone know how to fix the PFPD detectors?

I use PFPD with Agilent 7890B. The PFPD signal suddenly decreased. When you injected sulfur species compounds, some of the peaks disappeared and some of the peak signals are very low and broad. Like H2S and COS peak disappeared and DMS broad peak. The photometric tube works fine. The carrier flow rate Air 40 mL/min, H2 50 mL/min and make up N2 is 5mL/min. If the N2 flow is too high, the PFPD cannot be ignited.

Hello, Does anyone know how to fix the PFPD detectors?

I use PFPD with Agilent 7890B. The PFPD signal suddenly decreased. When you injected sulfur species compounds, some of the peaks disappeared and some of the peak signals are very low and broad. Like H2S and COS peak disappeared and DMS broad peak. The photometric tube works fine. The carrier flow rate Air 40 mL/min, H2 50 mL/min and make up N2 is 5mL/min. If the N2 flow is too high, the PFPD cannot be ignited.

The broad peak sounds more like inlet or column flow problems than a problem with the detector.

When was the last time inlet maintenance was performed(changing septa and liner and gold seal or swabbing out the inlet)?

Has the column been trimmed or replaced?

Hello, Does anyone know how to fix the PFPD detectors?

I use PFPD with Agilent 7890B. The PFPD signal suddenly decreased. When you injected sulfur species compounds, some of the peaks disappeared and some of the peak signals are very low and broad. Like H2S and COS peak disappeared and DMS broad peak. The photometric tube works fine. The carrier flow rate Air 40 mL/min, H2 50 mL/min and make up N2 is 5mL/min. If the N2 flow is too high, the PFPD cannot be ignited.

The broad peak sounds more like inlet or column flow problems than a problem with the detector.

When was the last time inlet maintenance was performed(changing septa and liner and gold seal or swabbing out the inlet)?

Has the column been trimmed or replaced?

Hello James,

Thank you very much for your reply!
I changed septa, liner and gold seal when the problem happened. First, I also thought that's the inlet problem. I also replaced a new column to the detector. It still has the problem. Some peaks sharp and some peaks broad. Is it the detector flow is not right?