Metal mobile phase containers

[Cliff Mitchell]

Hi All

What is your opinion of mobile phase containers made of metal (presumably stainless)? We may be evaluating these for a safety initiative. Off the top of my head, I am concerned about extractables and metals leaching into the mobile phase and contaminating the column. Also persistent exposure to dilute acid solutions that are stagnant in the metal reservoir may accelerate this process. Just wondering if anybody has any prior experience.

Also has anyone heard of metal reservoirs lined with glass or Teflon?

Thanks,
Cliff

[Bruce Hamilton]

There was a recent thread about passivation of stainless, and it would be very difficult to maintain with various aqueous/acidic mobile phases, and hopeless for aqueous phases with halogenated additives such as TFA.

Stainless is OK for most neutral organic solvents, and is routinely used by Biotage etc,. as large reservoirs for their normal phase flash systems. If you only use normal phase systems without additives, a suitable grade of stainless could be fine.

Glass also leaches metals, and is unsuitable for alkaline mobile phases - but so too are most silica-based chromatography columns, so is a good match. Plastic reservors exist for chromatographs that are metal sensitive, or use alkaline phases, ( eg ion chromatography ). However plastic containers can bind some molecules, allow some organics to permeate through, and may burn/melt in a fire.

Frankly, glass vessel are cheap, clean, simple to wash, provide quick visual indications of contents, and robust - hence most laboratory quantities of analytical and chromatography grade chemicals arrive in them. Make certain that proosed changes don't have unintended consequences.

I'm not sure what the safety initiative would be, but if it's the fragility of glass, there are plastic-coated glass vessels available. Review the cause of concern, and choosing a different shape/size of vessel, fitting, or location, might make the concerns disappear.

Bruce Hamilton

[Cliff Mitchell]

Thanks for your input Bruce. Your response raises the issue of cleanability. I wonder if a metal container exposed to acid and other common chromatographic reagents (buffers, ion pair reagents, etc) could ever been made clean again.

Thanks,
Cliff

[Consumer Products Guy]

Looks like Cliff is facing a similar situation to us. Pretty soon our company will want us to do chemical analysis without chemicals. I think the plastic-coated glass reservoirs are a good idea. On the other hand, I'd bet that other types of glassware are much more likely to be broken, like volumetric flasks, than are HPLC reservors. I can't remember anyone here ever actually breaking one, and they need to vent, so they're not under any pressure.

[Cliff Mitchell]

The real concern is the potential for shrapnel. In the event of a fire, the reservoir would essentially be a bomb (fueled by the organic liquid inside.

[Bruce Hamilton]

The real concern is the potential for shrapnel. In the event of a fire, the reservoir would essentially be a bomb (fueled by the organic liquid inside.

I would expect the plastic lines/cap insert would melt first, and you would have a Molotov Cocktail. If it's a big deal, put a PTFE 1/4" vent line in the cap connected to a simple bursting disk. Reagent bottles with screw caps are more likely to burst in a fire, but I've not heard of that either.

The normal method of breaking glass containers containing liquid chemicals is for the liquid inside to completely fill them, and the glass then breaks due to the extreme hydraulic pressures.

I've seen two winchesters of acetone break that way, and it was a very unspectacular "pop" as the bottom was pushed out and the acetone poured down the bench. Very funny, as the analyst had deliberately filled them to the brim to save money, forgetting the Dangerous Goods store was much colder....

The use of metal safety cans is justified for liquid volumes over a few litres, just because glass weighs so much, and modern safety cans have superior handles and self-closing dispenser nozzles.

I'd ask your safety people to cite why they believe there are explosion dangers from glass containers, and why they think metal might be superior.

There probably are over a million HPLCs on this planet, the vast majority of which would have glass storage containers, as they have for the last thirty years....

Bruce Hamilton

[Mark Tracy]

Don't ask the forum about health and safety. Call your local fire department and occupational safety and health agency. Their jobs are to know the laws and regulations that apply to your laboratory.

Sadly, some corporate safety officers are incompetent bullies. A good one is a pleasure to work with. If you have one of the former, complain to your lab director. If you have one of the latter, have a friendly discussion with him/her.

[Bruce Hamilton]

Don't ask the forum about health and safety. Call your local fire department and occupational safety and health agency. Their jobs are to know the laws and regulations that apply to your laboratory.

That may be true of the USA, but it's not always true in other countries, such as New Zealand.

Here, the law puts the responsibility on the site owner, the managers, and finally to the people using any toxic organisms or hazardous substances.

The site owner holds primarly responsibility for employees and contractors on their site, and local authorities only enforce building codes ( evacuation, fire exits, extinguishers, etc ) - they do not provide advice about safety issues. The site owner is required to locate all information, usually through specialist safety advisors or appointing a site safety officer - if the company is large.

Site safety officers under this regime have to be competent, friendly people, and can't be ignorant bullies, as they often have to locate and teach all the safe handling/disposal information.

The owner is required to ensure all people on site are trained/skilled in the safe handling, and the manager has to ensure that suitable resources are available and being used by all staff, and the employee is personally responsible for their own actions, especially if they could lead to harm to others.

If there is a serious accident, the site owner will face huge increases in their annual premium and punitive fines ( $100,000s ) if they allowed someboby to be negligent without having best practice in place. The premium is defined by industry record of accidents, and fortunately NZ laboratories have fairly-good safety records, so our premiums are fairly low compared to some industries.

Usually, serious, or repeated trivial, safety breaches by employees leads to instant dismissal, even if nobody is harmed. Employess can also be prosecuted by OSH if they were negligent, and caused an accident, except if they manage to kill themselves.

Different places, different rules...

Bruce Hamilton

[Mark Tracy]

If you are in Bruce's situation, then contact your insurance carrier. They should have an office that advises their clients on risk reduction. Or try your industry's national trade organization. The point is that this forum is ill-qualified to give sound advice on these kinds of matters.

[Bruce Hamilton]

If you are in Bruce's situation, then contact your insurance carrier. ... The point is that this forum is ill-qualified to give sound advice on these kinds of matters.

Sorry, I should have been more explicit. In NZ, and countries with similar safety regimes, the organisation's safety officer, or equivalent, is the first person to contact.

They have the delegated responsibility for the organisation, and would need to give approval before allowing employees to formally contact outside entities ( apart from unions etc., ).

Insurers here don't advise on safety.

There also are several safety fora/mailing lists on the Internet for people who want to discuss specific chemical safety issues with professionals.

Bruce Hamilton