Advertisement

Recurring issues of reduced peak areas and variability

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

4 posts Page 1 of 1
A couple of months ago, I've posted here regarding a problem that involved reduced areas for my analyte peaks as well as issues with reproducibility. The injection needle was changed out at the time, and that seemed to resolve the issue.

I'm purging the needle for 10 minutes prior to every run with primarily water. We're running biocides and moldicides on the HPLC. I'm hearing grinding noises during the injections while the needle is operating.

How often does one need to change out their needle in the autosampler? right now I'm thinking either the needle, seal pack, or the valve between the needle and syringe lines as the source of the issue.

Unit : Waters 717 plus autosampler
what instrument manufacturer?
waters autosampler 717 plus, right now I'm thinking either the needle, seal pack, or a valve issue.
may be ionization
4 posts Page 1 of 1

Who is online

In total there are 25 users online :: 1 registered, 0 hidden and 24 guests (based on users active over the past 5 minutes)
Most users ever online was 4374 on Fri Oct 03, 2025 12:41 am

Users browsing this forum: Semrush [Bot] and 24 guests

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry