How to clean glassware to eliminate contaminants for LCMS?

[BONGLINDA]

Dear all,
I am a LCMS beginner and I found that contamination is big problem when working with LCMS for picogam level. My lab have worked with HPLC-UV and fluorescent detector, we already have a SOP for cleaning glassware by soap only and we have no problem but this procedure does not work for glassware of LCMS: after cleaning, we try to test by putting mobile phase into extraction tube and shaking and injecting the resultant solution, we can detect a peak of analyte at level of LLOQ, and with that "dirty" glassware, the precision and accuracy of the method can not meet the requirement. Now I am trying to write a procedure to clean LCMS glassware to eliminate or minimize the contaminants. Could any one please give me some experience of cleaning glassware for LCMS?
Thank you very much in advance!

[Paulhurleyuk]

In my experience, for picogram level LC-MS/MS, most labs only use 'virgin' glassware. They will either dispose of used glassware, or demote it to other tasks within the lab, but definetlly never use the same piece of glassware twice for LC-MS/MS analysis.

This is not only due to the possibility of cross contamination from your analyte but also the effect of residues from cleaning solutions and other contaminats that can ruin an analysis (things like platicisers, PEG, detergents etc)

Regards,

Paul.

[BONGLINDA]

Thanks Paul. I and my colleagues are almost exhausted with cleaning glassware. You are right, it is not cross contamination only: We tried different ways and we found out several procedures which gave us no contaminants but when did experiment with those "cleaned" glassware, the results were unexplainable again, we really want to cry! . However, how to use "virgin" glassware now? We will do analysis for BE study, each day at least 50 samples, 50 glass tubes for liquid liquid extraction and 50 tubes for evaporation of organic solvents? Please, anyone in lab with LC-MS/MS could share experience with us? I have looked in many forums and did not find anyone have the same problem with me? Are you all use virgin glassware? Please help, help, help!

[JGK]

One of my previous companies was Japanese owned. he sent me over to the parent company to train in LC-MS/MS. Over there disposable products are so expensive that a huge amount of recycling/cleaning goes on.

The LC-MS/MS group used "virgin" pipette tips, HPLV vials and caps which were then cleaned and passed on to the LC team.

Non-recyclable glass tubes were individually hand-cleaned before entering the standard lab cleaning process (by sonication then through a laboratory dishwasher).

This process was not totally infallible but contamination from "clean tubes" was rare.

When I got back to Canada where, relatively speaking, labour costs were more expensive compared to consumables, we sourced disposable products for the LC-MS/MS procedures wherever possible.

[BONGLINDA]

Dear JSK,
My country is in the same situation you have mentioned in Japan, it is almost unacceptable if we use anything one time. Everything we should clean, clean and clean. The labour cost is too cheap compared to buying new tubes and also the procedure to buy anything is not simple (I guess that many of you can not understand the reason-we belong to governmental sector). Can you imagine: all plastic micropippet tips we also clean several times although the tips are "real" disposable, so how can we dispose glass extraction tubes. Total glass tubes in my lab are only about 200, and every year we only can buy about 100 more. We also have plan to use "virgin" one and later pass the "dirty" to the LC team. However, we can't do that way with glass tubes? Could you please help us the procedure to clean, not only for contamination but also for other things as Paul mentioned?
Thank you very much!

[JGK]

As I said in my previous post the non disposable (or recyclable) things like the glass extraction tubes were first thoroughly cleaned by hand by a technician using detergent and a cleaning brush and a lot of effort.

The hand cleaned tubes were then placed in an ultrasonic bath for two hours. they were then cleaned again in a laboratory glassware washer using the most rigorous cleaning program.

These tubes could then be re-used by the LC-MS/MS group.

If you are limited in what you can buy each year, I would recommend buying the highest quality product you can. Glass tubes will not last indefinitely and will wear out with constant use.

[BONGLINDA]

Dear JSK,
Which solvents had your lad used to ultrasound the tubes? I have found a document of WATERS for cleaning, they mention to use nitric acid 10% and methanol and acetonitrile. We have used nitric acid 10% or perchloric acid for 30 minutes and rinse with water only, not clean in washer again as you said. The contaminants seemed to disappear (only appear at acceptable level) but the results of experiment were very strange.
Also, could you please tell us which type of detergent had been used in your lab for cleaning? We use normal powder soap for clothes washing. WATERS says that can not use detergent for LCMS glassware but some other laboratories use detergent, I do not know which way is the best one, we can not try again and again day by day with cleaning job. The LCMS system is too expensive and my boss asks us everyday - when we can start real analysis?

[JGK]

As far as I know, they were just in an ultrasonic bath with distilled water only (possibly in neutral detergent solution). The subsequent treatment in the laboratory glassware washer incorporated an acid wash as part of the cleaning cycle (I don't know which acid was used, some use acetic or phosphoric acids).

They had a dedicated staff to do the routine glassware cleaning and the items were just passed to them.

[Paulhurleyuk]

I appreciate the difference in budget and resources between industry and goverment/acedemic labs. My experiences have all been in industry.

I have worked in labs where they did wash glassware (not for LC-MS/MS though) where they typically used a specfiic lab detergent (I remember several being sold under the Decon name) that is designed to clean well and rinse away with little residue.

However, for a Bioequivalence study, I think you have to ask the difference between the cost of doing all this cleaning and the potential cost of loosing a batch of samples to contamination, Generally the cost of using new glassware and throwing it away is negligable compared to the cost of patient recruitment and running the study.

Or you could use the advise given by one of my university lectures, to rinse everything with a saturated solution of pottasium dichromatein conc sulphuric acid. That will certainly get rid of any chemical residues, but it's not a nice procedure at all (I hesitate to suggest it, because it is very hazardous - please don't try this at home !)

Regards,

Paul.

[Peter Apps]

A method that I have used for GC glassware working down to sub ng levels was to do a normal wet wash (detergents, rinsing etc), dry at 120C and then bake at 450C. This is hot enough to oxidise anything organic. I used each piece of glass as soon as it cooled to room temp, becuase if it stood around the surface picked up contaminants again from the air.

Peter

[BONGLINDA]

Thank you all for suggestion.
We have used sulphocromic acid as Paul mentioned but still can't get the clean tubes and injection vials.
We will try to bake my tubes as Peter but I am wondering how good my tubes are, I don't have any information about heat-bearing ability of my tubes.
We understand the risk when using all the "dirty" glassware for BE study but hopefully in the future the situation will change and we can use all disposable stuff. At the moment, we still have to struggle with this cleaning work first.
If you have any other clues, please let us know, you will be highly appreciated.
Best regards.

[kerri]

Our lab cleans glassware by a soak in Nitric Acid/HCl/H2O (equal portions) for 1-2 hours and then rinse them well with ddH2O followed by air drying (or bakeout if you prefer). Of course, we reuse the acid wash. My lab has never had a problem with this procedure.

Kerri

[smkh]

Can you have just a one virgin glass tube and test it as you test the cleaned one to do comparision , may your contamination comes from another sources not from the glass tubes?!

[Don_Hilton]

If you use previously unused glassware do you ever see the background contamination? (As I read the thread, it looks like you only have the problem with reused glassware - but I want to be sure that I understand correctly.)

If this appears to be contamination from analyte in your samles sticking to the glass, can you tell us what the analyte is? Knowing that, it may be easier to give you a way to clean that analyte out of the glass.

It may be that you need to treat the glass to avoid the analyte sticking because if you are carrying over enough to measure - you lost that material from a previous sample you were analyzing - which could add to variability in results.

[betox]

I am working with a UPLC MS/MS and have the same problem. contaminatios, so we use disposable test tubes of 15 and 50ml with caps.

Wash glasses is very difficult and always remains contaminants.

hope this help you!