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You answered this question on 08/19/10
Questioner: Kelli
Category: Chemistry (including Biochemistry)
Private: No
Subject: the difference between 1 in 10 and 1:10
Question: Could you please clarify the difference between 1 in 10 and 1:10 - I been having an ongoing debate for years about this and I just want to double check to see who is right. My company actually has a standard operating procedure for this that does it the way I think it should be done but lots of others dispute this method. Please clear this up for us. Thanks
Answer: Greetings!
You've hit on a debate that I've had in each and every academic biochemistry lab I've gone to at some point or another. This has caused many bitter fights, some tears, many many repeated experiments, and misunderstandings.
Honestly, I think your company has the right idea in that they just put it into the code of operations and leave it at that. The 'best' solution I've had so far is either to put it to a vote or just have it declared on high and everyone has to comply.
But anyway. To explain in case someone else reads this and doesn't understand the question, the debate on the table is:
If you have a 1:3 solution that is ethanol:water, is that 33% ethanol or 25% ethanol?
In my experience, people who had extensive chemical laboratory-based training (especially analytical chemistry or physical chemistry) before coming to biology tend to read that as 'one part ethanol *and* three parts water' which means it's 25% ethanol. (Classically trained chemists maintain that this is the 'correct' method. Analytical textbooks agree. I fall in this camp, personally, but see below.)
Folks who haven't had the benefit of as many chemistry lab classes (or only biological labs, which tend to be less anal-retentive than analytical chemistry) tend to read it as 'one part ethanol *out of three parts total*', which means it's 33% ethanol. If you're not used to the nomenclature, this makes a heck of a lot of sense. It certainly LOOKS like a fraction. Most of the biologists I've talked to in the field maintain this is the correct way to go.
I honestly think this is a 'po-tay-toe'/'po-tah-toe' argument in the science community at this point. There was the equivalent of trench warfare in one of my labs over this, with neither side willing to give in so you had to pay attention to whose initials was on the label to understand what 1:3 meant.
In short, just be aware that folks in labs have diverse backgrounds. Avoid the pseudo-religious fervor that sometimes comes up due to questions like these. When you join a new lab, ask what the policy is and stick to it. Whenever you get a new protocol, ask. It's annoying, but it saves repeating things later.
... but if you're looking at a bottle with the initials 'TKR', it's 25% ethanol.
Questioner: Kelli
Category: Chemistry (including Biochemistry)
Private: No
Subject: the difference between 1 in 10 and 1:10
Question: Could you please clarify the difference between 1 in 10 and 1:10 - I been having an ongoing debate for years about this and I just want to double check to see who is right. My company actually has a standard operating procedure for this that does it the way I think it should be done but lots of others dispute this method. Please clear this up for us. Thanks
Answer: Greetings!
You've hit on a debate that I've had in each and every academic biochemistry lab I've gone to at some point or another. This has caused many bitter fights, some tears, many many repeated experiments, and misunderstandings.
Honestly, I think your company has the right idea in that they just put it into the code of operations and leave it at that. The 'best' solution I've had so far is either to put it to a vote or just have it declared on high and everyone has to comply.
But anyway. To explain in case someone else reads this and doesn't understand the question, the debate on the table is:
If you have a 1:3 solution that is ethanol:water, is that 33% ethanol or 25% ethanol?
In my experience, people who had extensive chemical laboratory-based training (especially analytical chemistry or physical chemistry) before coming to biology tend to read that as 'one part ethanol *and* three parts water' which means it's 25% ethanol. (Classically trained chemists maintain that this is the 'correct' method. Analytical textbooks agree. I fall in this camp, personally, but see below.)
Folks who haven't had the benefit of as many chemistry lab classes (or only biological labs, which tend to be less anal-retentive than analytical chemistry) tend to read it as 'one part ethanol *out of three parts total*', which means it's 33% ethanol. If you're not used to the nomenclature, this makes a heck of a lot of sense. It certainly LOOKS like a fraction. Most of the biologists I've talked to in the field maintain this is the correct way to go.
I honestly think this is a 'po-tay-toe'/'po-tah-toe' argument in the science community at this point. There was the equivalent of trench warfare in one of my labs over this, with neither side willing to give in so you had to pay attention to whose initials was on the label to understand what 1:3 meant.
In short, just be aware that folks in labs have diverse backgrounds. Avoid the pseudo-religious fervor that sometimes comes up due to questions like these. When you join a new lab, ask what the policy is and stick to it. Whenever you get a new protocol, ask. It's annoying, but it saves repeating things later.
... but if you're looking at a bottle with the initials 'TKR', it's 25% ethanol.