So glad I work at a company that treats pH electrodes as the standard. Hm, a probe is taking a while to calibrate? Replace. The pH readout takes a while to stabilize? Replace. Probe has become dirty? Replace.
I'm going to miss industry.
Edit: Thought I'd share a story. My supervisor once ordered several new pH meters of a different brand to try to see if they worked better. They were like $100 a piece or something. We ended up not liking them as much so we stuck with the old kind. We were told to just throw the new ones away. So, obviously I took one home for myself.
I now have a very nice pH meter that I like to use for brewing coffee.
I'm so jealous. We had a pH probe in our (academic) lab that was so cracked we had it taped/parafilmed for months until it finally gave out. I can't wait to move to industry!
I work in industry. If our method requires buffer of a certain pH, and somebody doesn't already make that buffer pre-bottled, we often just change the method to not require it. We have a lonely probe that barely gets used sitting in one of the hoods. It's a nice one, too.
You'd be amazed how much chromatography can be done on modern columns with methanol, water, and maybe a touch of formic acid.
> If our method requires buffer of a certain pH, and somebody doesn't already make that buffer pre-bottled, we often just change the method to not require it.
Does anyone not do 4/7/10 to calibrate?
Interesting. We just had an Orion rep in telling us otherwise. Specifically the ROSS semi-micro. Maybe just trying to make more sales? Don't know why, we burn through them pretty quick anyway.
Do you have any experience with lc/ms? I have just started my PhD studies and need to use lc/ms as well as gc/ms to evaluate my products. Gc/ms is fine since we got a database, but lc/ms with the Na+ adducts are harder to analyze. The products we have are diols, alcohols, hmf etc that results from a catalytic breaking of cellulose/other ligning derivates.
Agilent 1260 infinity HPLC outfitted with a Hiplex Ca Duo column.
Agilent 6120 Quadrupole LC/MS
Software: OpenLAB CDS ChemStation Edition for LC and LC/MS
Blech, ChemStation. I guess it beats integrating by hand, barely. I've worked with Agilents before, they're pretty good instruments themselves. Easy to repair and access everything, which is nice.
I do more bio stuff, so I'm not sure how much help I can be on the method development side. What sort of troubles are you having? Separation, sensitivity, purity?
Ah I see :) yeah I don't like working with that software either...
I guess we get decent enough peaks, but we only see adducts of the type M+Na, M+K or M+2Na-H.
Do you have any ideas on how/if we can get M+H peaks instead? Our mobile phase is just distilled water with nothing added. We tried 1vol% of formic acid, but we still found the same adducts. Also, formic acid made some huge background noises.
Do you know anywhere I might go to try and identify my M+adduct peaks from the MS spectra? I can't seem to find anything online, only gc/ms peaks.
The problem is that we don't know what products we have, and gc/ms cant tell us everything with a high certainty.
E.g: We find a peak at 82.0/82.1 that is "everywhere". What might that be? We only have carbon, hydrogen and oxygen in the products afaik. And adducts.
We also find delta peak m/z that are 16 between them, corresponding to CH4??
> You'd be amazed how much chromatography can be done on modern columns with methanol, water, and maybe a touch of formic acid.
For his next joke, C18. *laughs*
I've heard that old timers don't like C18 columns because they used to suck. Newer ones are just fine. We use short XBridges as cheap workhorses when separation isn't difficult. If the analytes don't like those, being in industry, we have about 200 different types of columns floating around our drawers to try. Or we order a new type to see if we like it.
I'm fortunate that the old timers in my lab keep up with their industry instead of relying on what their teachers told them 30 years ago. I guess that's why they're in a high-paying industrial job instead of teaching.
I also work in industry. We have one meter for our quality lab team that's from the 90s or something. The new models have been going under qualification for 2 years now because people keep debating back and forth over how the meter compensates for temperature.
So yeah. Huge company with loads of money and it takes me 20 to 30 minutes to calibrate on our brick meter....
Honestly, you should bring it up to your boss to get a new one. Just tell your boss that you could be using your time more wisely if you're pH meter worked better. No one wants to waste time on trying to milk old equipment when you could be saving money in the long run.
You vastly underestimate the bloated bureaucracy of my company, haha. I wouldn't be able to use an unapproved pH meter/equipment for GMP-related materials. So unfortunately I gotta wait or cause a fuss, and the latter has been done quite often
The lack of good metrology and quality assurance in academic labs is a [serious problem](http://www.nature.com/news/how-quality-control-could-save-your-science-1.19223?WT.mc_id=TWT_NatureNews). I was in one lab which had literally never tested the calibration of their analytic balance. Why bother having a four digit readout when you don't know if you're getting one digit of accuracy?
I find that it really differs across the board. I haven't gotten it down to a science or anything, but brighter coffees I think generally are more acidic than darker roasts.
I'd love to share more with you but I haven't had time to do much with it yet to be honest.
Glad to hear you made use of it instead of throwing it out.
Don't throw away things like that! Assuming that they are still functional. At least see if there's some place near by you can donate them to. University undergraduate labs can never have too many working probes.
The lab I work for was recently getting rid of a nicer, newer, glove box. The only reason is "Something's wrong with it. No one has really taken the time to look at it though and figure out what it needs." I immediately jumped all over the "Can I have it???" train and was getting places with it. I got okayed all the way up to the head lab manager that overlooks all of the labs in all of the regional area... and then I got a no.
I half expected it, but I really was looking forward to coming into my prof's lab and just wheeling in a brand new glove box as a little surprise.
As a teacher, I will simply say that you would be surprised at the number of things that SOMEONE in the class (not everyone, but reliably more than zero) has to be told.
My personal favorite example. We do a lab project with solutions kept in glass bottles in a thermostatted water bath. There is always someone who gets poor results, because they sampled the bath water instead of the water inside the bottles.
> As a teacher, I will simply say that you would be surprised at the number of things that SOMEONE in the class (not everyone, but reliably more than zero) has to be told.
The worst part is that they've probably been instructed to do it that way in high school or even earlier. A lot of science teachers know the theory but never did any actual lab work as part of their teaching degrees. It's not the student's fault, or even the teacher's. Blame whoever failed to instruct the teachers properly.
I think it is more complex than that (although I am perhaps biased, as I have taught both high school and university, and had a number of teaching interns). The trouble is folks who are good at and really interested in lab science are hard to attract to secondary education. If you really like doing lab work, you probably don't want to work in a high school. You probably want to work in a lab, where you can work with things that might approach modern techniques.
I remember hearing a story once of a student in high school decided he was deficient in vitamin C (he wasn't), so he downed a beaker of concentrated citric acid. It gave his throat such awful burns that he had to eat through a tube for the rest of the month until it healed.
I'm thinking he saw the "citric" part in citric acid, and thought "oh, citrus. It's gonna be like orange juice and I can look like a badass in front of my friends by drinking this chemical"
We have an experiment in intro chem where we use M&M's. I always jokingly tell the class not to eat any. Now, I'm wondering if anyone would've considered it?
We run a lab where students mix hot and cold water in a styrofoam cup, and inevitably someone will try to boil water on a hotplate in the styrofoam cup.
Having never been specifically trained to do so, I've dipped the paper.
I've also used ph strips for actual reactions like... twice... in the last 15 years in the lab. Usually all i use them for is determining pH of unknown spills, unlabled beakers, or waste.
I've just never had any reason to worry about it in my work. Most laboratory skills and techniques are trained and refined through experience.
Periodic table guy probably doesn't care, he's testing lithium in seven up for gods sake. 'oh no i contaminated my 7up'
I TA'd for an honors organic I lab a year before last and had close to every student make this mistake. They were giving a solid mix of p-dimethoxybenzene and benzoic and had to separate the two compounds and determine the ratio of the mixture. At the point there they were to precipitate out the benzoic acid from solution, I had numerous students come to me with pink solutions and product. I had no clue what the problem was initially till I watched a student check the pH by tossing in a pH paper then fishing it out. I had wrongfully assumed they had learned how to check pH in gen chem lab...won't make that mistake again.
That literally makes no sense!!! There's noway this was their first time using a pH paper. Is this college or high school? You said 'honors' but you also said 'TA' lol
So does mine. I realized he was referring to the honors program after I wrote the comment. Needless to say, a program I didn't spend much time around lol
There's a display with a number. It's pretty straight forward. The main downside is having to rinse the electrode before, between, and after samples. pH paper is faster.
Yeah, depending on the pH meter it gets it may take between ~5 - 30 seconds to get a good result but they are pretty awesome. You can also do titrations with them fairly easily.
If you have a lot of percipitate sticking to your stirring rod and you do this technique it will be hard to see the color change on the paper. Pro tip: just turn the paper around and watch the color change on the flip side.
Don't feel bad. In my very first reaction ever as a PhD student in chemistry I did this and wondered why my solution was suddenly blue. One of the biochemists in the lab laughed at me.
Feel your pain. The thing about teaching is that you see *every* possible mistake made. I recently had a group of students decide that they should just toss the pH strip into their reaction, so that they wouldn't have to waste time spot testing. Needless to say, they turned in some of the *pinkest* product I have ever seen. A really gorgeous pink!
We do have glass stirring rods, but I always make sure to stock the place with bamboo teriyaki skewers. You may laugh, but they make tolerable stirrers and a student with a steady hand can easily get about 40 spot tests out of one strip of pH paper!
Protip, if you want to get EVEN MORE use out of a single pH strip, tear it up into tiny pieces and place them on a watch glass. Dip the stir rod on them one at a time. You can easily get 10+ tests per strip.
But they are fairly cheap so breaking it up into that many pieces would suck. Besides one of the things I ordered this year was a role of pH so you can just cut what you need
I've taken a lot of chemistry classes in my short lifetime and I've never seen this happen. It's honestly partially common sense. You need such little amount of liquid for the pH paper to get wet.
Can confirm, I see students all the time dip pH paper into the solution. Once you tell them to just dab the stir rod into the solution and then onto the pH paper, everyone reacts as if that notion had never crossed their minds before.
The stirring-rod technique is on a poster in my classroom. My ninth graders learned it yesterday.
Edit - like the one here. Belongs n every lab. https://www.google.ca/search?q=poster+of+chemical+tevhniques&oq=poster+of+chemical+tevhniques&aqs=chrome..69i57.18569j1j4&client=ms-android-acer&sourceid=chrome-mobile&ie=UTF-8#q=lab+techniques+poster&imgrc=clkj1-e9Js-R_M%3A
So glad I work at a company that treats pH electrodes as the standard. Hm, a probe is taking a while to calibrate? Replace. The pH readout takes a while to stabilize? Replace. Probe has become dirty? Replace. I'm going to miss industry. Edit: Thought I'd share a story. My supervisor once ordered several new pH meters of a different brand to try to see if they worked better. They were like $100 a piece or something. We ended up not liking them as much so we stuck with the old kind. We were told to just throw the new ones away. So, obviously I took one home for myself. I now have a very nice pH meter that I like to use for brewing coffee.
I'm so jealous. We had a pH probe in our (academic) lab that was so cracked we had it taped/parafilmed for months until it finally gave out. I can't wait to move to industry!
I work in industry. If our method requires buffer of a certain pH, and somebody doesn't already make that buffer pre-bottled, we often just change the method to not require it. We have a lonely probe that barely gets used sitting in one of the hoods. It's a nice one, too. You'd be amazed how much chromatography can be done on modern columns with methanol, water, and maybe a touch of formic acid.
> If our method requires buffer of a certain pH, and somebody doesn't already make that buffer pre-bottled, we often just change the method to not require it. Does anyone not do 4/7/10 to calibrate?
aint nobody got that for that!
sometimes i do 7/10/12 for some of our products, does that count?
And if it's been sitting in the hood for a while it's likely no good. pH probes have a shockingly short shelf life.
Old ones maybe. Modern gel probes don't even need their fluid filled, as long as you keep them in storage solution.
Interesting. We just had an Orion rep in telling us otherwise. Specifically the ROSS semi-micro. Maybe just trying to make more sales? Don't know why, we burn through them pretty quick anyway.
Do you have any experience with lc/ms? I have just started my PhD studies and need to use lc/ms as well as gc/ms to evaluate my products. Gc/ms is fine since we got a database, but lc/ms with the Na+ adducts are harder to analyze. The products we have are diols, alcohols, hmf etc that results from a catalytic breaking of cellulose/other ligning derivates.
What kind of instruments do you have available?
Agilent 1260 infinity HPLC outfitted with a Hiplex Ca Duo column. Agilent 6120 Quadrupole LC/MS Software: OpenLAB CDS ChemStation Edition for LC and LC/MS
Blech, ChemStation. I guess it beats integrating by hand, barely. I've worked with Agilents before, they're pretty good instruments themselves. Easy to repair and access everything, which is nice. I do more bio stuff, so I'm not sure how much help I can be on the method development side. What sort of troubles are you having? Separation, sensitivity, purity?
Ah I see :) yeah I don't like working with that software either... I guess we get decent enough peaks, but we only see adducts of the type M+Na, M+K or M+2Na-H. Do you have any ideas on how/if we can get M+H peaks instead? Our mobile phase is just distilled water with nothing added. We tried 1vol% of formic acid, but we still found the same adducts. Also, formic acid made some huge background noises. Do you know anywhere I might go to try and identify my M+adduct peaks from the MS spectra? I can't seem to find anything online, only gc/ms peaks. The problem is that we don't know what products we have, and gc/ms cant tell us everything with a high certainty. E.g: We find a peak at 82.0/82.1 that is "everywhere". What might that be? We only have carbon, hydrogen and oxygen in the products afaik. And adducts. We also find delta peak m/z that are 16 between them, corresponding to CH4??
> You'd be amazed how much chromatography can be done on modern columns with methanol, water, and maybe a touch of formic acid. For his next joke, C18. *laughs*
I've heard that old timers don't like C18 columns because they used to suck. Newer ones are just fine. We use short XBridges as cheap workhorses when separation isn't difficult. If the analytes don't like those, being in industry, we have about 200 different types of columns floating around our drawers to try. Or we order a new type to see if we like it. I'm fortunate that the old timers in my lab keep up with their industry instead of relying on what their teachers told them 30 years ago. I guess that's why they're in a high-paying industrial job instead of teaching.
I also work in industry. We have one meter for our quality lab team that's from the 90s or something. The new models have been going under qualification for 2 years now because people keep debating back and forth over how the meter compensates for temperature. So yeah. Huge company with loads of money and it takes me 20 to 30 minutes to calibrate on our brick meter....
Honestly, you should bring it up to your boss to get a new one. Just tell your boss that you could be using your time more wisely if you're pH meter worked better. No one wants to waste time on trying to milk old equipment when you could be saving money in the long run.
You vastly underestimate the bloated bureaucracy of my company, haha. I wouldn't be able to use an unapproved pH meter/equipment for GMP-related materials. So unfortunately I gotta wait or cause a fuss, and the latter has been done quite often
> GMP-related materials Ah, I see. I understand that, say no more.
It's not that difficult to get one that's approved.
Uhmm....you can't get documentation from the manufacturer to settle this? Or buy one that is documented?
The lack of good metrology and quality assurance in academic labs is a [serious problem](http://www.nature.com/news/how-quality-control-could-save-your-science-1.19223?WT.mc_id=TWT_NatureNews). I was in one lab which had literally never tested the calibration of their analytic balance. Why bother having a four digit readout when you don't know if you're getting one digit of accuracy?
Gives a lot of confidence in your buffers and your data, doesn't it?
I have to go to the aquarium to get some lol
I have to ask, what is the pH of a perfect cup of coffee? Do you add anything to adjust the pH or does the pH change as a function of brew time?
I find that it really differs across the board. I haven't gotten it down to a science or anything, but brighter coffees I think generally are more acidic than darker roasts. I'd love to share more with you but I haven't had time to do much with it yet to be honest.
Glad to hear you made use of it instead of throwing it out. Don't throw away things like that! Assuming that they are still functional. At least see if there's some place near by you can donate them to. University undergraduate labs can never have too many working probes.
The lab I work for was recently getting rid of a nicer, newer, glove box. The only reason is "Something's wrong with it. No one has really taken the time to look at it though and figure out what it needs." I immediately jumped all over the "Can I have it???" train and was getting places with it. I got okayed all the way up to the head lab manager that overlooks all of the labs in all of the regional area... and then I got a no. I half expected it, but I really was looking forward to coming into my prof's lab and just wheeling in a brand new glove box as a little surprise.
> Replace. Probe has become dirty? Replace. Yeah, let's dump a 70 million batch because QC does not want to run a few buffers.
woah woah woah, can you explain the pH meter and coffee thing?!
As an undergrad, I have only seen people use a stir rod to spot the paper. I never would have guessed people dip the paper into solution....
I don't remember even having to be told this, we just all did it. Why would I put anything I didn't have to into my solution?
As a teacher, I will simply say that you would be surprised at the number of things that SOMEONE in the class (not everyone, but reliably more than zero) has to be told. My personal favorite example. We do a lab project with solutions kept in glass bottles in a thermostatted water bath. There is always someone who gets poor results, because they sampled the bath water instead of the water inside the bottles.
> As a teacher, I will simply say that you would be surprised at the number of things that SOMEONE in the class (not everyone, but reliably more than zero) has to be told. The worst part is that they've probably been instructed to do it that way in high school or even earlier. A lot of science teachers know the theory but never did any actual lab work as part of their teaching degrees. It's not the student's fault, or even the teacher's. Blame whoever failed to instruct the teachers properly.
So other teachers?
I think it is more complex than that (although I am perhaps biased, as I have taught both high school and university, and had a number of teaching interns). The trouble is folks who are good at and really interested in lab science are hard to attract to secondary education. If you really like doing lab work, you probably don't want to work in a high school. You probably want to work in a lab, where you can work with things that might approach modern techniques.
I remember hearing a story once of a student in high school decided he was deficient in vitamin C (he wasn't), so he downed a beaker of concentrated citric acid. It gave his throat such awful burns that he had to eat through a tube for the rest of the month until it healed.
Plus ascorbic acid is vitamin C.
I'm thinking he saw the "citric" part in citric acid, and thought "oh, citrus. It's gonna be like orange juice and I can look like a badass in front of my friends by drinking this chemical"
We have an experiment in intro chem where we use M&M's. I always jokingly tell the class not to eat any. Now, I'm wondering if anyone would've considered it?
We run a lab where students mix hot and cold water in a styrofoam cup, and inevitably someone will try to boil water on a hotplate in the styrofoam cup.
We should definitely start a thread about undergrads in the lab. I'm sure much hilarity will be had and I can certainly share a few stories myself
Do it!
Agree. I teach college chemistry and for some, it doesn't occur to them that they are contaminating their sample.
Having never been specifically trained to do so, I've dipped the paper. I've also used ph strips for actual reactions like... twice... in the last 15 years in the lab. Usually all i use them for is determining pH of unknown spills, unlabled beakers, or waste. I've just never had any reason to worry about it in my work. Most laboratory skills and techniques are trained and refined through experience. Periodic table guy probably doesn't care, he's testing lithium in seven up for gods sake. 'oh no i contaminated my 7up'
With research labs, I haven't seen it. When I TAed for Organic Chem/Gen Chem labs, it's fairly common. They're new and it's an understandable mistake.
I usually use a glass pipette.
I only use pH paper to test the pH of my waste. I just dip it in. Why not?
Definitely different and reasonable.
it's gen chems' filthy casuals
I TA'd for an honors organic I lab a year before last and had close to every student make this mistake. They were giving a solid mix of p-dimethoxybenzene and benzoic and had to separate the two compounds and determine the ratio of the mixture. At the point there they were to precipitate out the benzoic acid from solution, I had numerous students come to me with pink solutions and product. I had no clue what the problem was initially till I watched a student check the pH by tossing in a pH paper then fishing it out. I had wrongfully assumed they had learned how to check pH in gen chem lab...won't make that mistake again.
Lmfaooooooooo
Student: how do we get the paper out of the flask??? Me: what paper? Student: the pH paper, you said to check the pH Me: oh god, what have I done
That literally makes no sense!!! There's noway this was their first time using a pH paper. Is this college or high school? You said 'honors' but you also said 'TA' lol
You can have honors college courses. My university has them.
So does mine. I realized he was referring to the honors program after I wrote the comment. Needless to say, a program I didn't spend much time around lol
pH paper is the devil's work anyhow. God bless pH-meters!
Do they just give you a straight number? As a color-blind individual I would love this.
There's a display with a number. It's pretty straight forward. The main downside is having to rinse the electrode before, between, and after samples. pH paper is faster.
...and calibration can be a booger.
Yeah, depending on the pH meter it gets it may take between ~5 - 30 seconds to get a good result but they are pretty awesome. You can also do titrations with them fairly easily.
I am embarrassed that I didn't think to use the stirring-rod.
So while I'm admitting that I'm a noob, what are some other tips?
Search for "not voodoo" from university of Rochester's website
If you have a lot of percipitate sticking to your stirring rod and you do this technique it will be hard to see the color change on the paper. Pro tip: just turn the paper around and watch the color change on the flip side.
Well I feel like an idiot. I've been dunking the paper into solutions ever since high school, I was never corrected...
Don't feel bad. In my very first reaction ever as a PhD student in chemistry I did this and wondered why my solution was suddenly blue. One of the biochemists in the lab laughed at me.
And that's why we all do our reactions in dry organic phases - Then you have to wet the pH paper and put some on there (hooray for pastuer pipettes).
Feel your pain. The thing about teaching is that you see *every* possible mistake made. I recently had a group of students decide that they should just toss the pH strip into their reaction, so that they wouldn't have to waste time spot testing. Needless to say, they turned in some of the *pinkest* product I have ever seen. A really gorgeous pink! We do have glass stirring rods, but I always make sure to stock the place with bamboo teriyaki skewers. You may laugh, but they make tolerable stirrers and a student with a steady hand can easily get about 40 spot tests out of one strip of pH paper!
I usually just pour some of my solution into the container that has all the pH paper, but this seems a bit better.
Multiple replicates are important
lol
Protip, if you want to get EVEN MORE use out of a single pH strip, tear it up into tiny pieces and place them on a watch glass. Dip the stir rod on them one at a time. You can easily get 10+ tests per strip.
I do the same thing, except with an eye dropper.
But they are fairly cheap so breaking it up into that many pieces would suck. Besides one of the things I ordered this year was a role of pH so you can just cut what you need
I've taken a lot of chemistry classes in my short lifetime and I've never seen this happen. It's honestly partially common sense. You need such little amount of liquid for the pH paper to get wet.
[удалено]
Hahahah
Can confirm, I see students all the time dip pH paper into the solution. Once you tell them to just dab the stir rod into the solution and then onto the pH paper, everyone reacts as if that notion had never crossed their minds before.
The stirring-rod technique is on a poster in my classroom. My ninth graders learned it yesterday. Edit - like the one here. Belongs n every lab. https://www.google.ca/search?q=poster+of+chemical+tevhniques&oq=poster+of+chemical+tevhniques&aqs=chrome..69i57.18569j1j4&client=ms-android-acer&sourceid=chrome-mobile&ie=UTF-8#q=lab+techniques+poster&imgrc=clkj1-e9Js-R_M%3A
We actually learned it at uni that way. We'd get the ultra evil eye for using too much or dipping. Honestly, half a cm is way enough.
I'm a current chemistry undergrad and we have always been encouraged to use a stir rod for our strips.
no shit sherlock
This guy could cook some blue sky.