Cleaning to Remove Hydrocarbons

Since every thing you are already doing is very sensible but still not working. I will go a little outside the box in suggesting something you may try.

There is a product called Willard Water. It is a catalystic containing or altered water that was developed by a geochemist specifically for cleaning hydrocarbons with water.

It has gained a market as a health food.

You will find it on the web. You will clearly want the variety of their product that does not already contain carbon. Do not try to measure the Ph or dissolved solids of the solution. The water can permanently affect the function of these meters. Which is something I can no explain, but have observed.

It seems like the process you use is satisfactory, just need a little run time prior to use in testing to burn off the remaining methanol and acetone. However, unless you are looking for methanol and/or acetone, small peaks after cleaning in those times should not effect discerning the larger peak later when you are looking for heavier organics. Maybe you just increase the heat a little or the bake time to evapoarte further organics off the components before use, if needed. I would not change cleaners, unless it is recommended by the manufacturer, as this could throw the sensitivity/calibrations in the system off (especially if the residue has a catalyst in it) or even contaminate the system.

We are the manufacture and have been having problems with hydrocarbon contamination after building the burners. This has been an on and off problem recently. We have reviewed our procedures and people cleaning and assembling the burners; but have not been able to identify where the contamination is occuring.

Any suggestions on cleaning teflon after the machining process. We were wondering if the water solubale coolant may be leaving a residue in the teflon (teflon being some-what porus).

Thank You for all your responses...

Gas Man

Would a short visit to an abrasive booth help? Walnut shells, or plastic beads should not damage, or mar the appearance.

Simple exposure of your parts to clean air will result in a thin layer of carbon. One way to remove it is to plasma clean the parts just prior to use. Even one hour between cleaning and using the parts will result in some contamination.

Use an ultrasonic bath with an aqueous based degreaser. (contact me privately if you want the name of one that works really well). Clean the parts in the ultrasonic unit and then rinse them with acetone to remove residual water. after that place the parts in a vacuum over at 25 or so degrees to remove the acetone residue.

The "sometimes" in your original post suggests air contamination to me, or some othe post-cleaning contamination.

If your FID is part of a GC, the following practical guide must be followed.

1) Is the gas carrier free of contaminants?. Is it certified?

2) Was the injection port cleaned?. Does the liner contain glasswool?. This material acts as guard column.

3) How old is the column?. (check if black dots are inside the column), if positive, cut 6 " of both sides. If it is too old, replace it.

4) Was a previous result reviewed?. Sometimes, a sample can contain high concentrations of organic material. If you find that a sample containing heavy organics was analyzed, then you can conclude that the contamination came from it.

If all these issues mentioned above passed the QC, then you clean the detector. The

FID detector is mostly cleaned by baking it to a temperature that is 20-30 degres higher than the temperature of operation. Bake it during 24 hours.

Hydrocarbos are mostly soluble in hexane and DCM. Try to use these solvents to clean the parts of the detector.