We are observing inconsistent peaks in HPLC analysis of our drug products. LC-MS analysis had produced peaks at MW 207/413, 263, 258, 149.
Online research showed that these peaks could be due to LC-MS contamination from phthalates.
My question is could this contamination occur during HPLC analysis/sample prep. also?
Thank you
Yes, sometime contamination occurs.It happened many time with me and with our students in our lab.
Phthalates are unfortunately everywhere in the LC tubing, solvents sample equipment etc etc. Its very difficult to get around this a GCMS has less contamination but still has some.
An option i have done if an LC-MS is your only option is to firstly preclean all the LC tubing if its new, this will take some of the contaminants away. You can get ultra-pure solvents and use lots of procedural blanks. The blanks wont remove the issue but will help to identify and you can omit those peaks and work around it.
Hope this helps
G
I agree with the comments above. Phthalates are everywhere and contamination could be from your lab processes or in the LC-MS. Running blanks of two kinds might allow you to work out where they are coming from. If you run solvent only samples on the LC-MS that should reveal contamination from somewhere within the machine or the mobile phases. If those are clear then you can prepare blank samples with your actual samples and you should detect any contamination from the lab processes. Of course if they are coming from everywhere then you will still get phthalates in everything. The blank samples will give you a background though and allow you to identify which peaks are not from your sample. Be aware that even using plastic pipette tips can introduce phthalates to your sample. We always use microsyringes if we are really worried about getting phthalates in samples (which is most of the time) but I know that is not practical if you are processing large numbers of samples.
yes, Agree with that, We are also facing contamination of Pthalates....
Pthalates are extractables and Leachables component from plastic used anywhere.
you can use high grade of solvents from J. T. Baker chemical which might be solve your problem.
In addition to that minimize the use of plastic material during the processing of your samples. for example...
1) you can preserve your sample in Pre washed Glass volumetric flask.
2) Use Triple distilled water and highly pure solvent said above.
3) you can use Glass recovery vial for LC-MS injection instead of Plastic vials.
4) used freshly prepared solution.
5) wash the system thoroughly.
6) Processed your sample for blank also.
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