O start with, plastic vials must be prcolating some molecules fronm plastic even in distilled water -vasant phadke

I shall confirm soon. If u want to go to any lab in Mumbai give me address and i shall do ur work upto ur satisfaction

I have experienced with this problem. I would suggest you that you must perform your experiments in glass vials. Because peptides stick to surface of plastic vials, so you will lost peptides. But in glass vials you will not face this problem.

Thanx

It's a real problem. When very small quantities of sample are available it is easy that it "disappears". And the problem is not easy to solve. Some peptides attach themselves better on glass surfaces; others, usually less polars, attach themselves better on plastic. But by my experience, if you have the peptide solution in acidic media, usually is better using glassware.

I beleive Fisher sells coated conical autosampler vials for reduced protein binding. I think they are glass but even if you test the different vials there's a chance that you may also be losing some protein in the system if it sticks on the tubing in certain parts. Although may unlikely if it's in ACN.

Everything depends on the hydrophobicity of the analytes, the pH, or any solvents. The best advice I can give you is to "do the experiments" as part of method validation. In some cases, when large amounts of uninteresting protein are present, they take up the surface on tubes or tubing, in some sense, protecting/displacing low concentration analytes. The best advice though is to select the right tubes, pipette tips, vial caps, etc. by comparing them as a method is developed.

If you're forced to use plastic vials, you can add some 0.1% Formic Acid which will help free some peptides stuck to the wall.

Hi

I think you must use glass vial,because plastic vials would cause some problems while you have peptide samples.

I agree with Wagner. I am using preferentially sialinized glass vials which discourage any interaction analyte (proteins, peptides or any other polar compound) - glass. Deactivated glass inserts are also very useful, especially in case of low volumes. Just an example, I am pretty happy in using deactivated glass vials for phosphopeptide analysis by Orbitrap at low concentration.

Hope can help ;)

Stella

It is better to use glass vials at low concentrations and no heating is required.

The fact that peptides/proteins can attach to the surface of the vial has nothing to do with the concentration being below 100 ppm. They always tend to stick to surfaces, it's just that at low concentrations this may significantly alter the protein/peptide concentration in solution or even deplete it, thus it becomes a problem at low concentrations. It is called protein/peptide adsorption, by the way, and you shouldn't doubt it :)

And wow! may I just say that this commmunity is great! I just registered yesterday, and today I got a notification that someone had a problem I might be interested in. So I came here and saw that multiple people had already answered it. Very active community.

I agree with Rune. All the discussion in this topic is a matter about concentration. If you concentrate your sample maybe you can still get some peptides or proteins in solution.

However, some companies sell low-binding plastic vials. I've used them to prepare tryptic peptides to MALDI analysis. They seem ok. But if you are planning to analyse your samples by LC/MS you should avoid plastics at all. Normally, they've got a lot of contaminants as detergents, phtalates and PEG. In some cases they can be very annoying, mainly if your analyte has an m/z value close to the contamination.

Thank you people sharing your experience about this issue. We use glass vials by default and we considered them quite safe and this was not an issue until I've heard that glass vials also have potential risk. We work in the low ppm range and with complex matrices so we can't afford loosing our peptides. I will definitely try both plastic and glass and report you back.

We use two approach to solve the problem, proteins/peptides especially when below 100 ppm may attach to the internal glass surface of a vial and so no analyte of interest will enter the (nano)LC-MS system during injection.

1). Use Low protein Bind eppendorf (http://www.eppendorf.com/int/index.php?pb=636fc84343fa2cc2&action=products&contentid=1&catalognode=19439) to process your peptide and protein sample;

2). Use plasma or 3%BSA buffer as the solvent, but not water or organic solvent.

Great discussions. When you put a solute in solution, there is always a problem for non-specific binding to the surface of the container that will cost your material. It's a issue for the solute to distribute between the surface and solution. You do not notice the problem often at high solute concentrations since the total loss to the surface adsorption may be less than 1-2%. The issue becomes significant at low solute concentrations. In order to get better recovery in the solution, do following: (1). try to minimize both the surface interaction by using low binding material and the surface area exposed to the solution; and (2). try to increase the solubility in the solution; and (3). add something that competes the surface binding but not interfere with your analysis.

Thanks.

All suggestions are pretty good n every suggestion contain good example also.

As per my Opinion you should use glass vials of any good brand not of local quality and more over better quality vial are already deactivated, no need deactivate additionally.

I know many people do not recommend using plastic vials for LC-MS/MS. But We i have used plastic vials from Dionex. they never gave me any problems. Our machine is high mass accuracy( LTQ Orbitrap Velos) . Infact the MS grade formic acids (thermoscientific) are sold in plastic bottles of good quality. So there should not be any problem . But we do wash the vials with water + methanol + water + Ms grade methanol finally and dry it and then we use it. In fact our tips for pipettes are plastic too. it is really hard to avoid plastics here. WE never had problems. Engineers from the MS instrument companies always suggest use of Glass vials and avoid plastics. They were even surpised to see the ms grade formic acid in plastic bottle. but we did not have problems. we did check with glass vs plastic vials. We do work on low concentrations. peptides from gel samples.

We usually put a carrier into the buffer or solvent in which our sample is dissolved, when at low concentrations. This can help minimize losses of the sample to adsorption. We use dilute BSA or dilute glycogen. As long as the carrier doesn't interfere with your assay, you should be okay.

In our lab, when we need to work with particular peptides (highly positive charged) we wash our plastic vials before the use: ACN+0.1% TFA, 30mins soncation, fresh ACN for a final washing step and the owen to dry them.

good dicussion with nice examples. I agree with ying qu

We were doing some protein fluorimetry experiments a while back and of course we were working with very low protein concentrations. We compared three different glass and three diferent plastic vials/tubes. On the whole, the adsorption of the protein to the glass vials was two or three times higher compared to the plastic tubes. We got by far the best results using Eppendorf LoBind tubes, where the adsorption was minimal.

Hope it helps...

I have done some systematic studies and a lot of reading on this topic and here are some thoughts.

First of all, yes, it is true. No doubt about it. Proteins/peptides, sometimes even small molecules, stick to the surfaces.

Secondly, the issue is not simply plastic bad, glass good, or vise versa. It is unfortunately analyte dependent. Is it hydrophilic, hydrophobic? Any special interactions such as the common headache of phosphopeptides sticking to iron surfaces (think your injection valves). The exact material of the vial also matters. Is your plastic PE, PS (for some plates), MTX (my personal favorite)? Is it surface treated? What is the grade of the glass? Is the glass also surface treated? (hint, surface inactivation does NOT automatically mean better).

Thirdly I must report that many vendors has been working on this. For example there are bioinert HPLC systems using titanium parts, there is the Protein LoBind tubes from Eppendorf mentioned in this discussion above (unfortunately they don't make autosampler vials!).

Lastly, regarding glass vials, my personal experience has not been good. I have used the Waters vials and they sure have the problem!

1. Adsorbtionon to surface of glass or Poly propylene or plastic is completely dependent on HPLC index of peptide.higher the value more the adsorbtion.

2. If the value of HPLC index is higher, whether its plastic ,pp or glass they adsorb, in those cases to prvent non specific adsorbtion add BSA 2% should help you to minimize adsorbtion.

Good Point Wagner. Low absorption vials may be a good choice.

Has anyone had any problems with polymer stripping from protein LoBind eppendorf tubes please? Thank you

Do you mean that the walls of the tube are peeling off? I didn't have that kind of problems with my batch. If this is the case with yours, I think you should return the product and get a new batch...

What a great discussion. We have had these problems for decades in plates, vials, injection valves, microdialysis probes, tubing (glass, fused silica, Teflon, peek, stainless steel), filter disks...

Many variables, so one must test with specific situation.. A drug that does not stick to a tube in blood, may stick quite strongly once extracted..  All of the comments above are very fine.

 Yes, we have the similar problem that we find a lot of PEG signals when we tested the human plasma samples with MALDI TOF MS. But fortunately, the junk peaks don't impact too much on my analytes signals. Anyway, the polymer from the tubes are there!

Thanks for very interesting discussion. Please, can you quote papers, technical notes or book chapters where this issue is addressed?

We mainly used either silanized glassware or polypropylene (because it is relatively inert) when we could not use glass.  Vials and the inserts are usually glass (and cap liners are teflon), but if you have recovery issues, ie, trouble with the sample adhering to glass(adsorption), that's another issue you must resolve.   You have to consider the possibliility both before and after extraction and all equipment that is used during the extraction as well as for injection.  I recall there are also glass vials with a polyproplyene inserts. If your analyte sticks to glass, it may not stick to the plastic (and there are other types of plastic that can be tried, eg, polyethylene or polycarbonate, it all depends on what you are trying to analyze) and visa vera. Glass is usually the best bet to start with for biological samples, but it is not ever certain. Even then, you have another choice if it sticks to glass. You can dip the tubes/vials in a silanizing solution prior to use that makes it much less likely to adhere, but every compound in different biological matrices may behave differently. They also sell these types of treated tubes commercially too.

Here is an explanation by Sigma:  "Deactivation of Glassware:

Because the surface of laboratory glassware is slightly acidic, it can

adsorb some analytes — particularly amines. In low level analyses,

such losses can be significant. To prevent sample loss through

adsorption, glassware used in low level analyses usually is silanized.

Silanization masks the polar Si-OH groups on the glass surface by

chemically binding a nonadsorptive silicone layer to the surface,

in effect “derivatizing” the glass."

For example, one might notice that during analytical method development (using standards in the biolological matrix vs direct injection of standard),  a drop in recovery if there is adsorption. It is much easier if a radioactive compound is used for the tracer. You have to try alternates and determine where your compound/metabolite(s) is/are hung up.

This is very late to the original question however the following study is relevant:

The importance of using the optimal plastic and glassware in studies involving peptides

Anal Biochem. 2011 Jul 1; 414(1): 38–46.