Guest guest Posted January 14, 2011 Report Share Posted January 14, 2011 > How many drops (from an eyedropper)of alcohol does it take to make 100 ml? Please submit your findings so to see how far they deviate from one another. > You meant to write 1ml, right? Anybody who takes on the 100ml would have serious OCD issues and might snap if interrupted by accident, LOL. And what is the purpose of this experiment? Everybody will have different size eyedroppers, different techniques of dropping (more squeeze pressure, etc.), and of course, temperature enters into it. Anya McCoy http://AnyasGarden.com http://PerfumeClasses.com http://NaturalPerfumers.com Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 14, 2011 Report Share Posted January 14, 2011 ....would have serious OCD issues and might snap if interrupted by accident, LOL. oh thank goodness. i was staring at an at eye dropper and a 100mL beaker bracing myself for the task at hand. i agree... depends on temp, dropper and if you have light touch or firm touch with the squeezing... and how long you have been squeezing... trying to count to 100mL worth of drops.... much light, einsof Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 14, 2011 Report Share Posted January 14, 2011 Ok, just for chuckles I grabbed the 3mm disposable pipette and the bottle of Everclear (because I could ok!) Filled it cleanly to 1mm mark and dripped them out until done. 46 drops. Since I don't have any other graduated droppers or a graduated cylinder to drip into I can't tell you what other counts I get from my " Stain Droppers " or the droppers that came with my amber boston rounds. I would be happy to drip into a graduated cylinder with 1 ml increments if anyone wants to give me one to do it with -- B ....would have serious OCD issues and might snap if interrupted by accident, LOL. oh thank goodness. i was staring at an at eye dropper and a 100mL beaker bracing myself for the task at hand. i agree... depends on temp, dropper and if you have light touch or firm touch with the squeezing... and how long you have been squeezing... trying to count to 100mL worth of drops.... much light, einsof Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 14, 2011 Report Share Posted January 14, 2011 I guess I meant ml or cc not mm Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 14, 2011 Report Share Posted January 14, 2011 > ...would have serious OCD issues and might snap if interrupted by > accident, LOL. > > oh thank goodness. i was staring at an at eye dropper and a 100mL beaker bracing > myself for the task at hand. > i agree... depends on temp, dropper and if you have light touch or firm touch > with the squeezing... and how long you have been squeezing... trying to count to > 100mL worth of drops.... > much light, > Hi Ein, ListMom, .... I use 1ml serological pipettes...These are graduated, and I *make* my drops equal to 20 per milliliter...For ml totals 10 or over, I use a graduated 10ml cylinder...With it, there is an accuracy of about .1 ml... I also have a 50 ml beaker, more crudely graduated every 10 ml to 40... Working at that level, one would be better off weighing said alcohol on a sensitive scale or balance....Should be .01 gram or better...I say this, because if you take pure water as an example, it weighs 1 gram per ml....A drop at 20 per ml would weigh .05 gram...A .01 gram scale is sufficiently accurate to measure a drop within + or - 1/5 of a drop......** If you know the specific gravity of the material you are working with, you can switch back and forth between weight and volumetric... You can also carry accuracy comparably between your smallest and largest measurements, something extremely tedious to do at times, in the case of a volumetric system... BTW...the reason I chose 20 drops per ml, is that it was for a long time an AT standard, and I also asked a pharmacist what the standard was as far as eye drops (I was picking up a script for my Ma) per ml, and his answer was 20... Hope this helps... -- W. Bourbonais L'Hermite Aromatique A.J.P. (GIA) http://www.facebook.com/Le.Hermite **Note: A .1 gram accurate scale is only going to get you within 2 drops more ot less, since a drop (at 20 per ml) in this case weighs .05 grams...You can beat this by working with diluted components, but is a lotta fooling around and extra math... Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 15, 2011 Report Share Posted January 15, 2011 Of course. Please extrapolate from 1 ml. But you never know, people might have done 10 ml or more, and the bigger amounts might be more accurate. It depends on what you use to measure the resulting amount. As for me, all I have trust is a 10 ml pipette, and I have to stop off the end and drip into it. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 15, 2011 Report Share Posted January 15, 2011 I'm getting 50 eyedrpper drops per ml, which would be nice because it's divisible by ten and fits neatly into 100. (Too good to be true, n'est pas?) Serological pipettes must be different due to a larger diameter. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 15, 2011 Report Share Posted January 15, 2011 Oh, and the purpose of the experiment is because I doubt my own results and want a comparison with other people. I make perfumes by volume, although I know this is less accurate than making them by weight. However, it is the only thing I can do without buying a good, digital scale. Percent concentration formulas can be done using volume percent or percent concentration by mass. For example, a 1% solution by volume is 1 ml in a total of 100 ml, but it is also 1 g in 100 ml. Those two would yield different results depending on the density of the substance, as points out. For unprofessional me, making fragrances for personal use, it's good enough to drip. Yet, for standardization, I had better keep my drops the same size. However, for thick substances (resins) and crystalized substances (such as vanilla) there is nothing left to do but weigh them (on my old-fashioned slider scale) and hope for the best. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 15, 2011 Report Share Posted January 15, 2011 (Too good to be true, n'est pas?) > ...well... i guess we are all clear that OCD is not a necessarily a bad thing around this list. *giggle* now... how many angels fit on the head of a pin? much light, einsof Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 15, 2011 Report Share Posted January 15, 2011 > > mentioned a table she made, listing drops per ml of all > her " usual suspects. " > > I wonder if you'd be willing to share this with the list, . > > Cheers, > Kathleen > This issue of controlling variables like this is interesting. As a way to discuss this problem in scientific measurements, i have my new students try to answer the question " how many drops can you get onto the side of a penny before it overflows " . The answer of course is " it depends " . All kids had the same droppers, all were using water, and the values ranged from 15 on the low end to over 100 for the most careful students. I know you have all pointed this our already, but there are lots of things that make the " drops " method on that has to be used mindfully. Someone commented on scale precision - that's an excellent point. Using mass isn't a solution that's much better if your scale only has a precision of 0.1 g! You might get better accuracy with a calibrated pipette. 0.1 g could be the equivalent of an error of 2 - 5 " drops " depending on your drop size. Not so simple really... Ach! Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 15, 2011 Report Share Posted January 15, 2011 yeah, however, I use the hospital gauged one ml pipettes....20 drops per ml. I prefer the smaller ones as you dont have any excess run out at a tilt. evie Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 15, 2011 Report Share Posted January 15, 2011 > > yeah, however, I use the hospital gauged one ml pipettes....20 drops per ml. I prefer the smaller ones as you dont have any excess run out at a tilt. > > evie > There is an expensive but simple solution - pneumatic micropipettors. $200+ investment, so maybe only practical for a business or wealth dilettante. They can be bought in varus capacities 1-20 micro liters, 20 - 200 microliters and 200 - 1000 microliters for example. You dial up the volume, use disposable plastic tips that are dirt cheap and minimally wasteful (possibly reusable). They are so simple and easy to use and you actually get a reproducible result very small volumes. Some oils are tricky to pipette (if very viscous like agarwood or vetiver). Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 16, 2011 Report Share Posted January 16, 2011 Dial-up, micro-pipettes would be a dream-come-true. Like you say, it's too expensive for a hobbyist. Those of you who use pipettes, do you have a bulb that fits over your end? I had only my finger, and it was so nervewracking when I slip and, sploosh! -- get a flow instead of a drip. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 28, 2011 Report Share Posted February 28, 2011 > > Dial-up, micro-pipettes would be a dream-come-true. Like you say, it's too expensive for a hobbyist. > > Those of you who use pipettes, do you have a bulb that fits over your end? I had only my finger, and it was so nervewracking when I slip and, sploosh! -- get a flow instead of a drip. > Hey everyone! This is my first post and it's kinda on topic ;P I have a box of 500 3ml pipettes and I've decided it's time to move on and up. I'm planning on buying a few different sizes of glass pipettes and their corresponding plunger type top attachments along with a good scale. The scale I'm looking at has a 0.005 gram resolution and a maximum capacity of 400 grams. The scale costs around $250, so it's not exactly cheap, but it's got a lifetime warranty and I figure that it's going to save me time and effort in the long run. It's going to be so nice to be able to measure very small quantities of liquid, large quantities of liquid, and solids quickly with the same device and eliminate having to wash lots of graduated cylinders and beakers. Is there any reason that I should go with graduated cylinders over a good scale besides the price difference? Thanks for any help! Adam Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 28, 2011 Report Share Posted February 28, 2011 There are two schools of thought on measurements. I believe the most widely agreed upon notion is that weight is more accurate than volume, especially since volumes are so hard to measure accurately, and from material to material do not amount to the same amount. What I think, however, that you need is a micropipetting system with tips as opposed to the volumetric pipetting tubes, which are only as accurate as your eye. With the micro pipetting systems, you can set them as low as 0.1 of a microlitre reproducibly and accurately. This way, you can calculate how many microlitres to a gram per each material and use microlitres as " pseudo weight measurements. " Remember with a micro pipetter you can dial it back to some lower amount, with a straight pipette, you will have a difficult time cutting a drop in half, or 3/4 The idea of weight vs volume is more so that it is not the same ratio volumetricaly. If you have 10 drops of a material with an SC such that it weighs 1 g and 10 drops of something else such that it weighs .92 g then, if you try to copy a recipe that is given in ratio=grams you will not have enough of the lighter material in the mix. Personally, my opinion is that if you are making your own recipes, and calculating the interactions as you go along then you can use either method, as long as your dilutions are consistent and your pipettes are giving the same sized drop for thee same material each time; with the caveat that you remain consistent and keep good notes. Scaling up from a small recipe to a larger one will involve counting drops, or making volumetric measurements. Weight can be much easier because you can do it in reverse with a scale that has tare function. Simply place the source bottle on the scale and tare it out to 0. Then remove material until you get to the negative of the weight you desire and you have removed the weight you want. Using solvent flushing or good mechanical scraping you can get all the material you have removed into the mix. If you are not confident in that, then you need to include the pipette in the tare weight and as you remove material you place it into your measurement container and weigh both the remainder and the pipette to assure that any left behind is accounted for. To answer your subject question, there are official numbers of drops to an ml, but that is a technical thing. In reality the opening size of your pipette and the surface tension and viscosity of the material you are pipetting will all determine how many drops to the ml. Oh, yeah, and did I mention temperature? But a microliter is always a microliter so long as it is properly metered. -- B Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 28, 2011 Report Share Posted February 28, 2011 = DeLurking Quick reply. Use USP eye droppers to quickly arrive at your olfactory blend, taking copious written notes. Use a 10-25ml Erlenmeyer, so as to make it easy to blend & cork. Keep good records of suppliers & lot numbers. Once satisfied with the blend, translate the number of drops to grams, & weight on a 120gm or 300gm digital scale, then compare the two blends. There will always be slight variations, but you should be in the ball park. Drops into grams? No prob. Establish an approximate weight of each drop, by counting 30 or more drops on a scale, then dividing by number of drops used. Good lab technique is important. Gentle, deliberate squeeze of the bulb, and holding the dropper vertical. Do use a warm sand bath to accelerate the blending of resins and concurrently the aging. Careful with citrus. Use 'Secundum artem' for the amount & length of heat - No Open flame!!. There 'ya go, first secret of Perfumery 101. -= Parfumeur Privé =- =ReLurking Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 28, 2011 Report Share Posted February 28, 2011 = DeLurking Quick reply. Use USP eye droppers to quickly arrive at your olfactory blend, taking copious written notes. Use a 10-25ml Erlenmeyer, so as to make it easy to blend & cork. Keep good records of suppliers & lot numbers. Once satisfied with the blend, translate the number of drops to grams, & weight on a 120gm or 300gm digital scale, then compare the two blends. There will always be slight variations, but you should be in the ball park. Drops into grams? No prob. Establish an approximate weight of each drop, by counting 30 or more drops on a scale, then dividing by number of drops used. Good lab technique is important. Gentle, deliberate squeeze of the bulb, and holding the dropper vertical. Do use a warm sand bath to accelerate the blending of resins and concurrently the aging. Careful with citrus. Use 'Secundum artem' for the amount & length of heat - No Open flame!!. There 'ya go, first secret of Perfumery 101. -= Parfumeur Privé =- =ReLurking Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 28, 2011 Report Share Posted February 28, 2011 Thanks for the reply Bradley! Yeah, I can definitely see a micro pipette coming in handy to tweak out forumlas when working with very small amounts. Especially when working with undiluted oils that aren't too viscous. However, I'm very new to this scene and I've decided to start to dilute my materials before blending. That way I'll get to know the materials diluted and undiluted. Also, by diluting larger quantities of materials first, and then using portions of those in blends, I won't be needing to measure such small quantities of oils- making the micro pipette not as important at first. I can only afford a scale or a micro pipette system at this time, not both. I think I'll start with the scale since it's more versatile and I need a way to accurately measure weights of resins and thick liquids anyway. As for reverse weighing, I had not thought of measuring materials this way. I was thinking I would place the empty receiving container on the scale, tear it out to zero, gather an aproximate amount of material with a pipette, and transfer the exact amount needed to the receiving container by weighing the correct amount. Then I just switch to a new clean pipette, tear the scale, and add the correct weight of the next material. This way seems a bit simpler to me. Like I said though, I'm new to this so my reasoning may be off. thanks again for the help! Adam Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 28, 2011 Report Share Posted February 28, 2011 Thanks for the reply Bradley! Yeah, I can definitely see a micro pipette coming in handy to tweak out forumlas when working with very small amounts. Especially when working with undiluted oils that aren't too viscous. However, I'm very new to this scene and I've decided to start to dilute my materials before blending. That way I'll get to know the materials diluted and undiluted. Also, by diluting larger quantities of materials first, and then using portions of those in blends, I won't be needing to measure such small quantities of oils- making the micro pipette not as important at first. I can only afford a scale or a micro pipette system at this time, not both. I think I'll start with the scale since it's more versatile and I need a way to accurately measure weights of resins and thick liquids anyway. As for reverse weighing, I had not thought of measuring materials this way. I was thinking I would place the empty receiving container on the scale, tear it out to zero, gather an aproximate amount of material with a pipette, and transfer the exact amount needed to the receiving container by weighing the correct amount. Then I just switch to a new clean pipette, tear the scale, and add the correct weight of the next material. This way seems a bit simpler to me. Like I said though, I'm new to this so my reasoning may be off. thanks again for the help! Adam Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 28, 2011 Report Share Posted February 28, 2011 Wait until you start working with some viscous stuff, or until you end up putting in more drops than you want. It is one thing to add too much to an empty container. But when you add too much to a container with other ingredients already in it, you will find that you can't remove so well. Reverse, is just another tool in the arsenal. If you keep your eyes open you can get the micro's fairly cheap. I just got 3 for less than $50 total. Regardless of the system you use, take your time and be consistent. Good luck! -- B Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 28, 2011 Report Share Posted February 28, 2011 Wait until you start working with some viscous stuff, or until you end up putting in more drops than you want. It is one thing to add too much to an empty container. But when you add too much to a container with other ingredients already in it, you will find that you can't remove so well. Reverse, is just another tool in the arsenal. If you keep your eyes open you can get the micro's fairly cheap. I just got 3 for less than $50 total. Regardless of the system you use, take your time and be consistent. Good luck! -- B Quote Link to comment Share on other sites More sharing options...
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