Recently i had to use some hydrogen in the gas chromatograph, its used normally for the detector in a GC thats fitted with FID detector. But its also used (with a huge amount of care) as a carrier gas.
In the kind of GC/MS (mass spectrometry ) stuff i normally do, I use nitrogen as the carrier gas and Hydrogen is only used for the FID (flame ionization detector), this way your just burning a tiny amount of hydrogen in a little detector and there is little risk. But once in a while you need very fine accuracy, to put it in perspective look at it this way.
The three main carrier gasses used are Hydrogen,Helium and Nitrogen. To give you an idea of the differences compare them to a set of balances or multimeters.
Nitrogen would be your basic multimeter capable of measuring down to 1mV or a balance that has 3 DP and can measure roughly down to 1mg. Helium is like a half way decent meter that measure down to the 100's uV or 4DP on a balance. Hydrogen is your super duper bench meter that goes to 7 DP and if used as a balance can measure the change of air pressure by its mass!
So looking at that you would think Helium gives the best of all worlds and is the way to go, and it indeed is. But its got one awful set back, it's cost goes up and down more than gold or oil. Recently its been really expensive to buy analytical grade Helium, also science is trying to limit its use as much as it can to preserve stocks. The worry being we will run out of pure Helium, so with that in mind please do stop buying balloons filled with balloon gas! it contains some Helium and its a real waste of precious resource thats not easy to get hold of once we run out!
So most make do with Nitrogen, in all honesty its more than good enough in modern GC's anyway. Hydrogen you normally fit a sensor in the oven of the GC to detect leaks of it.
This is one reason i call it the worlds best criminal!! it gets out of almost anything!! If you think about party balloons and the fact they contain a proportion of Helium and bulked up with other gases, look at how quickly those metal film baloons go down! The helium molecules work there way through the metal film material and escape.
Hydrogen molecules are twice as small as Helium, so get through these films and just about everything else at twice the rate. Leave a hydrogen cylinder on and the torch off for a few months, come back and read the bottle gauge. 100% guarantee even the finest gas pipes will have slowly leaked the Hydrogen through there walls! Worse than that, when i first got hold of Hydrogen cylinders for the GC I got two of them.
The problem is here in the UK, analytical grade gas is very expensive, you cant just walk into shop and buy it. You need a supply contract from someone like BOC, these contracts are as bad as telephone landline contracts! Not only do you pay for the gas, but you pay for delivery and my pet peeve you RENT the bottle monthly!!
You cant buy a bottle outright (or at least i couldnt), so the cost breaks down like this. Gas price (last time i purchased some was 2017 Jan) Full sized cylinder and 3 9's grade (didnt need 4 9's as it was for the FID) was £198 + Vat for the gas, £57 deposit for the cylinder, £42 a MONTH bottle rental! and £41 delivery for 5 bottles of various gasses.
When i first got the Hydrogen they had a deal on, you could rent two cylinders for the price of one. So despite being advised not too i did this, turns out i made a mistake. The gauges i use are all certified and kept under certification, one reason they deliver the gas is so the driver can check you use the correct trolley to keep the cylinder on and/or the correct cage and location of storage.
They also check your gauges and pipes are in good condition. Using Hydrogen for a FID dosnt use much gas, in fact even using the GC every day for long periods uses a small amount, every day i would turn the cylinder off at the bottle with a bottle key and turn the gauges off. The second bottle had gauges fitted (i figured it was a safe place to store them) and was turned off at the bottle.
My bottles are kept on a trolley and in a secure cage inside a secure outbuilding, the pipework goes through the wall and terminates at the GC. After 8 months I was checking my gasses as the rep had called me asking why i hadnt ordered any gas for 8 months! Simple really as i hadnt used it all!
I do cheat a bit, some gasses if i need small amounts I make them, normally in a really old Kipps apparatus. But for things like system flushes with hydrogen I tend to make the gas and use that, it dosnt have to be ultra pure and is easy to make and dry the gas. So i tendto make my own CO2 when i can and the same with Hydrogen.
When I checked the unused Hydrogen cylinder i was shocked, it had lost around 12th of its starting volume!! I have a professional Hydrogen alarm in what i grandly call the gas room (stone shed slate roof and small
), partly because H&S recommends this and partly because two full cylinders of hydrogen leaking out and going bang would ruin my year badly, Also the building they in isnt insured! Mainly because despite the gas being brought by a incorporated/ LTD company, and the building technically owned by a LTD company, i cant get it insured!!
We are lucky as we own where we live outright, we cant remortgage it or take loans out on it but we do own every last inch of it. So we dont have to have building insurance, but i would like it. Because of what we do and the gas we keep, we cant get the insurance. Dosnt help that we also live on the same plot of land as the lab, but we can get house insurance.
Anyway back on topic.....
Solid steel cylinder and in good condition, purchased from one of the worlds best suppliers, no alarms have gone off but gas has obviously slowly got out some how. So in a bit of a panic i ordered a small Argon bottle to be delivered, when the driver turns up i ask him about the loss of hydrogen. He checks everything and gives it the thumbs up, so i ask where has my overpriced precious Hydrogen gone?
Apparently most people who buy the gas use it before they notice what i noticed, but he admitted that as far as he was aware there is no way to keep every hydrogen molecule locked up. Apparently the size of the molecule is such that it diffuses through most things, i asked if that included the thick steel cylinders, and he assured me no it dosnt get out that way, but it does slowly seep through the valves assembly where you attach the gauges.
Apparently taking the gauges off dosnt help, as i had turned off the actual cylinder so no gas was in the gauges. So the real point of the thread?
Well there is alot of talk about ion transfer bridges, salt bridges, PTM's (Proton transfer membranes). These are used alot in chemistry, especially electro chemistry and things like AD systems and Microbial fuel cells. The idea of them is pretty simple, you need something to make separate chambers for the Anode and Cathode, but you also need it to be easy for electrons to pass from one side to the other easily.
There are loads of designs and materials used for various purposes and reasons, they go from simple flower pot types made from terracotta, these are often soaked in a salt and used to separate the chamber/process. All the way up to special Proton transfer membranes, those things are great but there is the small issue of cost.
What i am looking for is something specifically to allow the transfer of electrons from H+ ions to go from the Anode to be oxidized at the Cathode and produce a charge. One side of the cell is mesophilic anaerobic (Anode side) and the other is highly aerobic thermophilic Cathode side. Now the PTM stuff is roughly £210 per sq cm!! So i have been looking at other materials, all have downsides and most would slowly poison the Cathode or Anode and kill off the cell.
THEN i got to thinking..... All i am doing is moving H+ over to a cathode cell to be oxidized at the cathode and produce a charge, the main loss in these systems is internal resistance, if you cut that then you up the efficiency of the cell, do that enough and you start to get a extremely attractive alternative green energy source with a massive benefit.
My sister had a friends party last week, she brought a party balloon home and today while reading emails i noticed it on the back of the sofa..... It isnt floating now, and its the foil type.... So no idea if this will work, but i might just have found a great material to use as a bridge that will certainly let H+ ions through it, its also cheap and while it does have a foil in it, it also has some kind of plastic membrane, its this membrane i am going to look at.
So Hydrogen the greatest escape artist of all time 'might' have provided me with a simple solution. The criminal part is the price and the fact its a mare to handle safely and really dosnt play nice with oxygen!!
In the kind of GC/MS (mass spectrometry ) stuff i normally do, I use nitrogen as the carrier gas and Hydrogen is only used for the FID (flame ionization detector), this way your just burning a tiny amount of hydrogen in a little detector and there is little risk. But once in a while you need very fine accuracy, to put it in perspective look at it this way.
The three main carrier gasses used are Hydrogen,Helium and Nitrogen. To give you an idea of the differences compare them to a set of balances or multimeters.
Nitrogen would be your basic multimeter capable of measuring down to 1mV or a balance that has 3 DP and can measure roughly down to 1mg. Helium is like a half way decent meter that measure down to the 100's uV or 4DP on a balance. Hydrogen is your super duper bench meter that goes to 7 DP and if used as a balance can measure the change of air pressure by its mass!
So looking at that you would think Helium gives the best of all worlds and is the way to go, and it indeed is. But its got one awful set back, it's cost goes up and down more than gold or oil. Recently its been really expensive to buy analytical grade Helium, also science is trying to limit its use as much as it can to preserve stocks. The worry being we will run out of pure Helium, so with that in mind please do stop buying balloons filled with balloon gas! it contains some Helium and its a real waste of precious resource thats not easy to get hold of once we run out!
So most make do with Nitrogen, in all honesty its more than good enough in modern GC's anyway. Hydrogen you normally fit a sensor in the oven of the GC to detect leaks of it.
This is one reason i call it the worlds best criminal!! it gets out of almost anything!! If you think about party balloons and the fact they contain a proportion of Helium and bulked up with other gases, look at how quickly those metal film baloons go down! The helium molecules work there way through the metal film material and escape.
Hydrogen molecules are twice as small as Helium, so get through these films and just about everything else at twice the rate. Leave a hydrogen cylinder on and the torch off for a few months, come back and read the bottle gauge. 100% guarantee even the finest gas pipes will have slowly leaked the Hydrogen through there walls! Worse than that, when i first got hold of Hydrogen cylinders for the GC I got two of them.
The problem is here in the UK, analytical grade gas is very expensive, you cant just walk into shop and buy it. You need a supply contract from someone like BOC, these contracts are as bad as telephone landline contracts! Not only do you pay for the gas, but you pay for delivery and my pet peeve you RENT the bottle monthly!!
You cant buy a bottle outright (or at least i couldnt), so the cost breaks down like this. Gas price (last time i purchased some was 2017 Jan) Full sized cylinder and 3 9's grade (didnt need 4 9's as it was for the FID) was £198 + Vat for the gas, £57 deposit for the cylinder, £42 a MONTH bottle rental! and £41 delivery for 5 bottles of various gasses.
When i first got the Hydrogen they had a deal on, you could rent two cylinders for the price of one. So despite being advised not too i did this, turns out i made a mistake. The gauges i use are all certified and kept under certification, one reason they deliver the gas is so the driver can check you use the correct trolley to keep the cylinder on and/or the correct cage and location of storage.
They also check your gauges and pipes are in good condition. Using Hydrogen for a FID dosnt use much gas, in fact even using the GC every day for long periods uses a small amount, every day i would turn the cylinder off at the bottle with a bottle key and turn the gauges off. The second bottle had gauges fitted (i figured it was a safe place to store them) and was turned off at the bottle.
My bottles are kept on a trolley and in a secure cage inside a secure outbuilding, the pipework goes through the wall and terminates at the GC. After 8 months I was checking my gasses as the rep had called me asking why i hadnt ordered any gas for 8 months! Simple really as i hadnt used it all!
I do cheat a bit, some gasses if i need small amounts I make them, normally in a really old Kipps apparatus. But for things like system flushes with hydrogen I tend to make the gas and use that, it dosnt have to be ultra pure and is easy to make and dry the gas. So i tendto make my own CO2 when i can and the same with Hydrogen.
When I checked the unused Hydrogen cylinder i was shocked, it had lost around 12th of its starting volume!! I have a professional Hydrogen alarm in what i grandly call the gas room (stone shed slate roof and small
), partly because H&S recommends this and partly because two full cylinders of hydrogen leaking out and going bang would ruin my year badly, Also the building they in isnt insured! Mainly because despite the gas being brought by a incorporated/ LTD company, and the building technically owned by a LTD company, i cant get it insured!!We are lucky as we own where we live outright, we cant remortgage it or take loans out on it but we do own every last inch of it. So we dont have to have building insurance, but i would like it. Because of what we do and the gas we keep, we cant get the insurance. Dosnt help that we also live on the same plot of land as the lab, but we can get house insurance.
Anyway back on topic.....
Solid steel cylinder and in good condition, purchased from one of the worlds best suppliers, no alarms have gone off but gas has obviously slowly got out some how. So in a bit of a panic i ordered a small Argon bottle to be delivered, when the driver turns up i ask him about the loss of hydrogen. He checks everything and gives it the thumbs up, so i ask where has my overpriced precious Hydrogen gone?
Apparently most people who buy the gas use it before they notice what i noticed, but he admitted that as far as he was aware there is no way to keep every hydrogen molecule locked up. Apparently the size of the molecule is such that it diffuses through most things, i asked if that included the thick steel cylinders, and he assured me no it dosnt get out that way, but it does slowly seep through the valves assembly where you attach the gauges.
Apparently taking the gauges off dosnt help, as i had turned off the actual cylinder so no gas was in the gauges. So the real point of the thread?
Well there is alot of talk about ion transfer bridges, salt bridges, PTM's (Proton transfer membranes). These are used alot in chemistry, especially electro chemistry and things like AD systems and Microbial fuel cells. The idea of them is pretty simple, you need something to make separate chambers for the Anode and Cathode, but you also need it to be easy for electrons to pass from one side to the other easily.
There are loads of designs and materials used for various purposes and reasons, they go from simple flower pot types made from terracotta, these are often soaked in a salt and used to separate the chamber/process. All the way up to special Proton transfer membranes, those things are great but there is the small issue of cost.
What i am looking for is something specifically to allow the transfer of electrons from H+ ions to go from the Anode to be oxidized at the Cathode and produce a charge. One side of the cell is mesophilic anaerobic (Anode side) and the other is highly aerobic thermophilic Cathode side. Now the PTM stuff is roughly £210 per sq cm!! So i have been looking at other materials, all have downsides and most would slowly poison the Cathode or Anode and kill off the cell.
THEN i got to thinking..... All i am doing is moving H+ over to a cathode cell to be oxidized at the cathode and produce a charge, the main loss in these systems is internal resistance, if you cut that then you up the efficiency of the cell, do that enough and you start to get a extremely attractive alternative green energy source with a massive benefit.
My sister had a friends party last week, she brought a party balloon home and today while reading emails i noticed it on the back of the sofa..... It isnt floating now, and its the foil type.... So no idea if this will work, but i might just have found a great material to use as a bridge that will certainly let H+ ions through it
, its also cheap and while it does have a foil in it, it also has some kind of plastic membrane, its this membrane i am going to look at.So Hydrogen the greatest escape artist of all time 'might' have provided me with a simple solution
. The criminal part is the price and the fact its a mare to handle safely and really dosnt play nice with oxygen!!
