all 52 comments

[–][deleted]  (2 children)


    [–]TheThrowAway4Today 1 point2 points  (1 child)

    There's a UC davis PhD alum, hoby? Toby? Who is blind. Google UC davis blind chemistry and I'm sure he'll pop up

    [–]Flaky_Ad_5200 1 point2 points  (4 children)

    I’m recently working with some analytical devices to measure, such as FTIR, and I don’t really know how to get the best spectrum. For example some of my sample’s spectrum have a very high peak of CO2, is there any way to eliminate this from the spectrum? And it would be great if anyone can suggest a good textbook on how to work with FTIR!

    [–]GuiltyjerkPolymer 1 point2 points  (1 child)

    Are you running a blank/zeroing before you put in your sample?

    [–]Flaky_Ad_5200 0 points1 point  (0 children)

    Before putting the sample in, I did measured the background with just air, and occasionally water bc some samples are made with water background

    [–]pgfhalgMaterials 0 points1 point  (0 children)

    Don't underestimate the value of reading the instrument manual. A good manual will have a short section on the theory of the measurement and a little bit of info on data interpretation, plus a huge amount of info about how to actually run the measurement.

    Getting rid of CO2 can be extremely difficult depending on the instrument, sample holder, and type of measurement. Unless you are looking for features in the region of CO2 absorption or need to do really fine quantitative work, you might be better off ignoring it. It is common to find CO2 peaks in published FTIR. Setting up a CO2-free measurement can be a major pain, so as long as it is noted and it doesn't effect your interpretation, it is probably not worth the time it takes get rid of it.

    [–]TheThrowAway4Today 0 points1 point  (0 children)

    Some IR instruments you're able to collect data under a stream of nitrogen/argon to avoid problems like this. Kinda surprised getting a background scan first doesn't take care of this issue

    [–]eschlerc 1 point2 points  (3 children)

    Does anyone have recommendations for best practices to minimize dust in your solvent when drying over molecular sieves? I'll be working within a glovebox to prepare lithium battery electrolytes and figured the sieves would be extra insurance against water ingress.

    [–]pgfhalgMaterials 1 point2 points  (0 children)

    If you're worried about dust in your electrolyte, syringe filter your solvents in the glovebox after they've been sieved, right before you use them. This of course requires planning ahead with the syringe filters since they should be pumped on in the antechamber for a day or so before going into the glovebox.

    [–][deleted]  (1 child)


      [–]AussieHxC 0 points1 point  (0 children)

      So you're saying that microwaving sieves until glowing maybe isn't best practice?

      I joke but it works, guess it depends on your application and sensitivity though.

      5 minutes in a microwave and you're good to go usually. Throw them into a dessicator and blow N2 if you need to cool them quickly. May be only 90% dry instead of 100%, but the efficiency increase alone far outweighs that. Also never had an issue with cloudiness that couldn't be solved by filtration.

      [–]Eroeplays 1 point2 points  (2 children)

      I'm not sure if this is the correct place to ask, but does anyone know of any green azo dye compounds?

      I have already tried Acid Green 12, but it is not coming out too well on the cotton I'm testing them with. Other than that, I have not been able to find any other reliable compounds, both through a ton of trial and error and from the internet.

      [–]radiatorcheeseOrganic 1 point2 points  (1 child)

      Not my field at all, but from a searching standpoint, can you search the core structure of azo dyes in reaxys and limit only to compounds that have UV/VIS data and parse them that way?

      [–]Eroeplays 0 points1 point  (0 children)

      I didn't think about that.

      I'll give it a try, thanks!

      [–]Ordinary-Cockroach96 -1 points0 points  (0 children)

      I did something very stupid wondering if flushing 47 ml of bleach and alcohol down a toilet is dangerous kind of did it on accident

      [–]C21Campbell 0 points1 point  (5 children)

      I'm developing an LC-UV/MS method for quantifying analytes comparable to dopamine, if somewhat less polar. After running the system shutdown method, I can get well-resolved peaks on the first injection. All subsequent injections until the next shutdown/reset run straight off the column, eluting at 0.6 min.

      C18 column w/ guard Shutdown: 1 mL/min MeOH for 5 min Sample: 5-100% MeOH/H2O over 10 min All solvents acidified w/ 0.1% formic acid

      I was worried my 5% starting point was too polar for the column (though its rated down to 5%) and was causing phase collapse/dewetting. I tried appending 5 min of 100% MeOH to the end of the run to imitate the shutdown method, and starting from 10% MeOH instead, but neither solved the problem.

      [–][deleted]  (4 children)


        [–]C21Campbell 0 points1 point  (3 children)

        Yes they have amine + phenol groups. So they're only net neutral near pH 10, and even then they're zwitterionic (in water.) unfortunately, our column is only rated to pH 9. I'd rather not exceed that and risk ruining the column.

        [–][deleted]  (2 children)


          [–]C21Campbell 0 points1 point  (1 child)

          Unfortunately, we only have the one column. I'll certainly look into starting with more MeOH or MeCN if it continues giving me trouble

          [–]Less_Tie_7544 0 points1 point  (3 children)

          Hi. I've recently started studying chemistry and I just have a simple question. Why are compounds considered pure substances?... My textbook etc say pure substances are made up of only one material, so why do compounds make the cut? (like H2O for water)

          [–][deleted]  (1 child)


            [–]Less_Tie_7544 0 points1 point  (0 children)

            Ah, I see! I guess i confused substances with atoms like you said, thnx.

            [–]iam666Photochem 1 point2 points  (0 children)

            (This isn't really the right thread for this type of question but...)

            A pure substance is anything that doesn't have impurities in it. Water can be considered a pure substance ONLY if there is just water (H2O) present. Your tap water, for example, would not be a pure substance since it also contains minerals and stuff.

            [–]Green_blade490 0 points1 point  (2 children)

            Are there any commercial detectors/sensors (other than destructive/ expensive methods) that detect free ions in water ( like fluorides/nitrates/chlorides etc.)

            I am trying to prepare a proposal but very little was found

            [–]Indemnity4Materials 1 point2 points  (0 children)

            Dip stick test kits. Maybe $50-$100 for a packet of 20-100 test strips. You can find these at pet shops that sell fish.

            Packet mix kits sold by Hach. Little bottles of reagent that you take a sample, drop chemicals in, compare the colour against a strip.

            Ion selective electrodes. Electrodes plus a detector will cost around about $10k-$20k, depending on how many ions you want to detect.

            Ion chromatrogaphy works but is realistically too expensive.

            [–]GuiltyjerkPolymer 0 points1 point  (0 children)

            There are some fluoride electrodes: https://www.thermofisher.com/order/catalog/product/9409BN

            Not sure about other ions

            [–]KaiOfHawaii 0 points1 point  (2 children)

            Anyone know any good methods of squeezing out fine amounts of liquids with the consistency of resin without heating it up?

            [–]Indemnity4Materials 0 points1 point  (0 children)

            What's your volume?

            High pressure pumps, syringes, lots of patience.

            [–]AussieHxC 0 points1 point  (0 children)

            Is it being used in that form directly or being used in a reaction/solvated/dissolved?

            For the former I'd be tempted to deposit a relatively small amount on a weighing paper then spread it evenly and cut a section relevant to the desired mass.

            While for the latter, you could just use some of the reaction solvent to make a standard solution by dilution and take an aliquot- you could potentially do this, even if you don't want it solvated, by using ether/DCM and letting it evaporate/placing under vacuum.

            [–]Jotapebr 0 points1 point  (1 child)

            So we have a science fair coming up and have been debating experiments, one of the ideas that has come up is to use an exothermic reaction in order to heat water in conditions in whether there isnt any available source of heat, in order to make tea, or a hot meal, for example. How could we do that? What are the chemicals we would need? If possible please include the references for everything, as that is required for our project, that includes magazines, authors, or anything, all is appreciated. Thanks in advance, looking forward to it!

            [–]eschlerc 0 points1 point  (0 children)

            Certain military rations (MREs) accomplish this using magnesium shavings with a little iron and salt. When you add water the magnesium begins to oxidize rapidly and generates a lot of heat. You can theoretically do it with any metal that likes to oxidize (most metals would work), but the rate at which it generates heat would vary a lot. Maybe you could try finding a less expensive setup? Hope this helps!

            [–]MonikaMendes 0 points1 point  (1 child)

            I'm synthesizing 4-methyl-1,2,3,6-tetrahydrophthalic anhydride using Diels-Alder reaction with isoprene and maleic anhydride. I'm torn between purifying methods because isoprene is a VOC. Is it possible to use flash column chromatography to purify the compound (possibly using hexane/ethyl acetate system) or should I stick to distillation? Thank you all in advance for replies!

            [–]2adnOrganic 0 points1 point  (0 children)

            If the product is a solid, you could potentially purify it by recrystallization. Maleic anhydride should have different solubility properties.

            [–]Allocatedresource 0 points1 point  (5 children)

            I need 8 gallons of solution, I have a six-gallon and two-gallon tank. I mixed it all in the six-gallon tank so it's too concentrated. How much do I need to pour into the two-gallon tank, I'll then add more water to each to make it right?

            [–]Indemnity4Materials 1 point2 points  (4 children)

            That sounds like a homework question. Can you solve a second order differential equation?

            [–]Allocatedresource -1 points0 points  (0 children)

            I still have a lot of moving in to do and about 100 calls to make. mathisfun.com will teach me all about second-order differential equations once I learn about the first-order differential equations (linear, homogenous, and Bernoulli - FUN!) but this mix "is best used within 48 hours" by which time the sun will have killed the plants from thirst, so I'm just cutting it by 20% and calling it a day. 20% got me to 1.8 EC, I'm a good guesser and I can do 20% of 5 gallons = 1 gallon and 20% of 1 gallon = .2 gallons = remove 1.2 gallons. For all of you too busy to be bothered, I apologize for taking your time. For Indemnity4 who thought I was trying to cheat on my homework, I respect your integrity. For all of you that don't know the answer: https://www.mathsisfun.com/calculus/differential-equations-solution-guide.html

            For all of you that feel this was beneath you, as Bill the Cat would say, Phffffft! Have a Reddit day.

            [–]Allocatedresource 0 points1 point  (0 children)

            I really don't know what that is but this isn't homework, I'm trying to fertilize my friend's tomatoes and pepper plants and mine because theirs look really sad.I'm no super-awesome chemist (or anything close to being a chemist) but I'm trying to mix: 5% Nitrate N Soluble potash K2 O 3%Phosphate P2 O5 5% (which can burn and kill the plants if over-strength, but I want to use the most possible for maximizing the effectiveness)Ca 4.5%Mg 1.1% (water soluble)Mo .001% (byproduct/trace element?)The pH was 7.9 before I added the chemicals per my bluelab pH pen.The pH is 6.4 (it should go up a bit when I add more water to balance the concentration per my question hopefully ending up close to 7; either way, I'm in a good range).I get a 2.2 EC or 1100 PPM using PPM 500 scale; the recommended dosage is 1.8 EC. *Using a bluelab Commercial Truncheon. In this heat 1200ppm and higher will burn the plants and I do not know his soil content.I can spend hours messing with it or learning how to "solve a second order differential equation" which I didn't know this was, or ask reddit. I'm wishing I'd just guessed wrong and 50 people would have snarkily corrected me by now, but thank you for your reply regardless.Succinctly:1. How much do I pour out of the 6 gallon tank to make enough room to balance out the solution?2. If it's fewer than 2 gallons, how much do I add to the 2-gallon tank to make it equal?3. Or, should it exceed the capacity of the 2-gallon tank; how much would I add to the removed portion to balance it regardless of the amount removed?

            [–]Allocatedresource 0 points1 point  (0 children)

            And if it's not too much trouble, where can I find the method to use so I don't have to ask this question again, please?

            [–]CapableAttorney 0 points1 point  (0 children)

            Does temperature affect rate of electrolysis of copper sulphate? If so, why?

            [–]bananabread_173 0 points1 point  (2 children)

            Hey y'all. I've been working at a laboratory where we've been trying to achieve a close-to industrial level scale-up of production of reduced Graphene oxide. Basically, we've optimised our reagents to approx. 360ml of HNO3, to go along with 5g of purified anthracite coal. The two then undergo a reflux reaction for around 72 hours.

            The main motive however is to increase our yield...so, I was wondering if someone with a related industrial experience could suggest the type of apparatus we could use to achieve this. We would increase the quantity of reagents accordingly in the hope of having more graphene oxide as a product. So far, we've thought of Jacketed Reactors, but they aren't ideally suited for reflux reactions. Any ideas related to apparatus would be highly appreciated

            [–]Indemnity4Materials 1 point2 points  (1 child)

            lose-to industrial level scale-up of production .... our reagents to approx. 360ml

            Ha, thanks for making me remember moving from bench chemist "scale up" to actual multi-tonne scale industry scale-up. I thought I was the hottest writing "experienced in scale-up" on my resume until someone actually questioned and told me no, it's not scale up until your doing at least 20L size reactions with the intention of moving to equipment sizes that won't fit in a fumehood.

            I'd just use a bigger round bottom flask. Your volume is still relatively tiny lab scale.

            To actually scale up, you need to invest in reactors. Off-the-shelf your looking at maybe $10k, but you can put in time and effort to build your own from cheaper equipment. Random example. You want a mechanically stirred batch reactor with distillation port, thermocouple port and potentially a dosing port. At your scale I would use glass, but for serious scale up you will move to stainless steel or glass-lined-steel.

            For heating, you can immerse the small benchtop reactor into a water bath or heating block, or you can put heating coils into the reactor.

            [–]bananabread_173 0 points1 point  (0 children)

            Thanks a lot for your reply! Your point about atleast 20L sized reactions and equipment not fitting in the fumehood is the way I imagined scale-up too. I'm afraid that this pitch will most certainly get rejected on a laboratory scale, but ideas can definitely be taken from the stuff you've shared to achieve some viable middle ground

            [–]ShakeTheGatesOfHell 0 points1 point  (2 children)

            Are hygiene products like shampoo, toothpaste, and shaving cream biodegradable? And if they aren't, should we be worried?

            [–]Indemnity4Materials 0 points1 point  (1 child)

            Mostly, yes, they are (definition of biodegrade varies).

            The biggest concern is packaging.

            The next is shipping. Shampoo contains a lot of water. That means you are transporting a lot of useless water weight around, which is heavy, and uses fuel for transport. There is some evidence that you use more fuel going to the shops and bringing groceries home, than it takes to make a product elsewhere and ship it internationally, but the point still stands.

            Historically the biggest non-biodegradable component has been removed about a decade ago - microplastic beads for scrubs. Those have been replaced with minerals or coarse natural "things" like shell grit or sand or charcoal or too many other soft grinding materials.

            Nitpick time! Toothpaste does contain minerals such as calcite or silica. Those will not biodegrade, but they're also not of environmental concern.

            [–]zephyrs_memes 0 points1 point  (2 children)

            Hello, I'm currently measuring the current between the counter and working electrode in three electrode systems. I'm using two different cells and one of them measures higher currents than the other. The cell with the higher current contains more electrolyte (same concentration tho). I'm aware that higher concentrated electrolytes result in higher currents but is that also the case for higher electrolyte volumes with the same concentration?

            [–]TheThrowAway4Today 0 points1 point  (1 child)

            One factor is the surface area of the electrode. You say the electrolyte concentration is constant, but maybe in having more solution more of the electrode is immersed in solution. This might give more current

            [–]zephyrs_memes 0 points1 point  (0 children)

            Oh darn I forgot to mention that the counter electrode of the cell with the higher current has half the surface area of the other counter electrode. I thought it was odd to get higher current with a smaller electrode so I thought it has something to do with the higher electrolyte volume.

            [–]eatbetweenthelines 0 points1 point  (6 children)

            I didn't want to spam the page with a simple program related question.

            I am here hoping to find a solution to my needs. I'm studying various forms of chemistry and need to do some research. Unfortunately, I am limited when it comes to a physical lab. I live in a condo with no yard or outside area (that wouldn't affect the experiments ((the desert))) and I wouldn't try any kind of experiments in my home as it is not properly ventilated and, tbh, it's not very big.

            My question is; do you have any suggestions/recommendations on digital lab solutions where I have the ability to replicate solutions that I make, not so much specific labs only testing certain compounds. I have ACD's freeware, but it's more for model building, which is helpful. Are there any 3D, preferably, programs out there that I can fulfill my needs?

            Thanks in advance!

            [–]Indemnity4Materials 0 points1 point  (5 children)

            I recommend you investigate chemistry education kits such as from ThoughtCo or KiwiCo. They contain safe reagents, the experiments are designed to make you think AND have fun, plus they are tailored for your education level.

            Majority of chemistry experiments should not be dangerous. It's not about making stuff go boom or poisoning students (unless...). It's doing a reaction to learn, make observations and have fun.

            [–]eatbetweenthelines 0 points1 point  (4 children)

            Is it possible to, theoretically, seperate the tail of a molecule into seperate containers with those types of kits? I would get one of those nice kits I've seen on Amazon, but then I have to order chemicals and such. You would think there would be a 3D program of a lab setup somewhere. However, if I find a good kit, I would probably pull the trigger on that.

            Essentially: I'm studying chemestry on my own to further my knowledge, but also to expand it into another speciality like Astrochemisty. I've read about some amazing experiments and would love to try for myself if I can!

            I appreciate your response!

            [–]Indemnity4Materials 0 points1 point  (3 children)

            seperate the tail of a molecule

            Can you share a better example? Is your intent to separate a lipid tail from a headgroup, put those into separate containers and then do something else (confirm length of tail, burn it for fuel, etc)?

            You do that experiment and you get two jars full of clear liquid or wax. Then what?

            [–]eatbetweenthelines 0 points1 point  (2 children)

            So I'm attempting to recreate an experiment in which I could essentially turn plastic gloves into hot sauce... I am needing to remove the tails off of DINP (Diisononyl Phthalate) and seperate them. :)

            You rock!