regarding tailing

[rrm1987]

during HPLC intially i.e., for first 10 runs peak tailing was not observed whereas after 10th run,peak tailing was observed.what could be the reason?
conditions:
mobile phase:meoh/water/acetic acid=30/70/1
analyte:ferulic acid

[Don_Hilton]

What matrix issues are there? As junk from sample matrix is deposited on the column (or other parts of the instrument) the analyte can partition into the junk and the small quantities of compund can be more strongly retained - becoming the tail of the peak.

So, what is the matrix - and if you are using something complex and dirty (like urine, bloodd serum, mud extract, etc.), have you done anything to clean it up. Also, what type of column are you using?

And have you taken any steps to rinse the column with mobile phase of a different composition to clean off junk?

[rrm1987]

i was trying to analyze the ferulic acid content in wheat bran.After treatment of some enzymes with wheat bran,the supernatant was analyzed for ferulic acid.
column:C18,5 micron

[Johnny Rod]

Have you re-made your mobile phase and samples? Are you close to the pKa of the analyte?

[chromatographer1]

This is why folks use guard columns and use them often.

Injecting non-eluting nasties onto a column offers all kinds of opportunity for sample to be attracted to the nasties and distort the sample plug in the form of 'tailing'.

I bet the tailing goes away with a new column installed.

best wishes,

Rod

[rrm1987]

you mean to say to use guard columns

[chromatographer1]

Once a new column is installed. Once the old column is contaminated with nasty binding components there is little use for a guard column.

Too late is the word if that is the case.

Rod