Community project; chirality checker ( optical refractometer)

[Osmosis Vanderwaal]

There have been a few times when I have been using methamphetamine, for instance, and I have wondered to myself, " this sure doesn't seem to be getting me very high. It tastes the same a usual, the crystals are pretty amorphous, this product doesn't really have the long slender parallelogram in cross-section shape that a shard of D(R) methamphetamine should have and it,s not a flat squarish flake reminiscent of a window pane which one would expect from L(S) methamphetamine. I'm confident a lot ofmyounseen the rantings of the man who bought a large amount from a crytocurrency leader, and when it didn't get him high, se sent it to a lab and discovered it was 72% L-meth. I think this happens a lot more than people realize. There are instructions and 100s of paragraphs of discussion on stripping D-meth from a racemic mixture. Currently, this is hard costly, expensive, or time consuming to detect.
There exists a device, that, when used properly, can measure the chirality of molecules. It's called a refractometer. It can measure how much and what direction a molecule bends light. The act of bending light is called optical activity. A molecule is only active if it is chiral. Furthermore if a molecule has more than 1 rotatable bond, all of the bonds must turn in the same direction for a molecule to be optically active. A refractometer, suitable for. Chemistry purposes costs about $1000 and up.

1S,2R ephedrine is not optically active. The net result on light is it is not bent. First it bends counter clockwise, then it bends clockwise, so the total is no change
1S,2S ephedrine is optically active first it bends light clockwise, then it bends light more clockwise

Racemic mixtures of isomers are not active. In theory the chemical has 50% leavorotary chirality and 50% dextrorotary, making the net result 0, but in life rarely ever does one encounter a perfect linear result. So 2-3° L or R is within the expected range for a racemic mixture. Every molecule, every bond even, has a certain amount of rotation and that number depends on factors like the temperature and the strength of a solution, so in order to get an accurate measurement these things must be taken into account and figured as variables into an equation.
The reality is, we don't need a $1000 device to see if a molecule rotates light and we don't need to accurately measure how much the light is bending. Knowing that it
Bends lights strongly CC
Bends light slightly CC
Doesn't bend light
Bends light slightly clockwise
Bends lightnstrongly clockwise
Is all I'm after, but I want it to be cheap and portable so I can use it to look at a product before I buy it. I have, in my possession, lots of "stuff" meaning items, that is think I can utilize to prototype a device and test/modify the design to optimize it's cost and ability.
I have 5v lithium batteries of all kinds. Ear buds have absolutely tiny batteries, and I have some from old scales, buetooth headphones, sex toys, tons of phone batteries ( but I was thinking about some of the tiny rechargeable 5v batteries) and led yea lights, railroad track type hobbyists led lights resistors uv led lcds, all of it. I've got a 3d printer. It was given to me and I've never touched it. I know it's all here and several rolls of filament. I will be making prototypes and I can send them to people to tweak and make improvements to. I have no intention of patenting or profiting from this idea or contraption. I think it would benefit the group and the world. Today I received the first pieces that I knew I didn't have laying around. This could be enough to make 20 or even 50 units

 

[Osmosis Vanderwaal]

I would love some technical assistance, as I've never even see a refactometer. Hopefully the likes of resident experts @WillD @Marvin "Popcorn" Sutton @GhostChemist @G.Patton can periodically check in and offer some details. For instnce

 

[FENTAMAS]

Refractometers are for another purpose, namely for measuring index of refraction, these devices usually can be very cheap and compact.
Device you're looking for is called polarimeter. It measures optical rotation of sample solution. Even manual ones are quite expensive and large.
Fortunately they are based on simple principles and can be reproduced in home settings, with some loss of precision of course.

All you need is light source, long thin glass tube with flat ends (you can glue glass to glass with epoxy) with some enlargement for air bubble (that's easy done with torch, soft tube and your lungs) and polarizing film or glass. For better precision also any lux meter (measures intensity of light, or illuminance).
Light source should be linear (or you need additional polarizer filter) and preferably with narrow spectrum as close as possible to sodium-vapor lamp value (589 nm) for easier comparison of your experimental measures of light rotation with literature data.
Good and and cheap source of such light could be 5mW 635nm red laser diode module without lens or with lens for so-called "fat beam". As we know, most laser diodes have linearly polarized coherent and monochromatic light. There are also LEDs with much closer spectrum to 589nm, but it's nonlinear and more wide, so maybe it should be additionally covered with some narrow band-pass filter if you want to get appropriate values.

Here you can see a good explanation of how it actually works:

Example of one of the cheapest commercially available manual polarimeters (from China similar ones could be bought for 300-500$):

 

[Osmosis Vanderwaal]

Thanks for your input and correction on terminology. A polarimeter starts at $1000, and what I'm trying to make is a refractometer ( iassume, but that might be loose terminology, I just want to see if a substance bends light 20° levao, 20° or more dextrorotary or just a couple of degrees either way ( to allow for enantiomeric excess). I bought those polarizing film sheets. I tried to take some off of an old phone, but it was not possible for me. I'm at a loss , understanding the light situation, but I have a lot of leads lcds and the such, but I'll buy the right thing as soon as I understand what that is. I'm an incredible narcissist, so there's nothing I can't do ( in my mind) I can print circuit boards, I got a 3d printer, uv and epoxy resin equipment. I'll open this wallet and buy whatever it takes. I could buy a polarimeter, but I can't haul it around and I don't need something that accurate. I would love to design something anyone can make out of a mints tin And a cheap monocle or toy ocular or...whatever I can make work that isn't a custom piece. In the next post I'll explain why I'm trying to do this. Unfortunately I am far from a chemist, I've never had a class or lesson in my life. I have the equipment equal to most high school chemistry labs, and I'm fairly well read on the subject, but very little lab experience.

 

[Osmosis Vanderwaal]

I said,
I used ph strips and went 2 points past the pKa and pKb each way