Guide to Melting Points: Start Accurately Testing Purity from Home with Ease for <$200 : coke | Torhoo darknet markets

I've been wanting to do a guide introducing people to melting points like this for a while. I just haven't had the time to put it together. It's not as polished as I wanted it to be, but I'd really just like to get this info out there since I think it's long overdue and has the potential to make very positive changes in this, and other communities if the knowledge starts propagating.

INTRODUCTION:

Checking the melting point of a sample is something anyone with the right tools can do, you don't need a fancy lab, special chemistry knowledge, or even any experience with home chemistry at all. You just need to invest a small amount of money in the right equipment and learn how to do the test.

All you need is a melting point apparatus, thermometer (unless you get a high quality apparatus with a built in thermometer), and melting point capillaries. All this stuff can be easily acquired for less than $200, you just need to buy used equipment off eBay.

Testing the melting point of a sample is a fast and easy way to estimate purity and identify substances. Many substances have experimentally determined melting point values that are published in academic journals or textbooks that can be found online. These values are referred to by chemists as literature values. You can find them by searching for "melting point of ____" or "_____ melting point". Usually on sites like wikipedia, pubchem, etc. but sometimes you'll have to check around.

Make sure you're specific. Many drugs have free base and salt forms. If you search for the melting point of cocaine, you'll get the values for the free base. You'd want to search for cocaine hydrochloride unless you want the free base values.


UTIILITY OF MELTING POINTS:
The reason melting points are so versatile is that they have a few properties we can use:

Pure substances will finish their transition from solid to liquid over a short temperature range. When you look up literature values you'll often only span one degree.

Pure substances will always melt at a higher temperature than the same substance mixed with adulterants/impurities. The presence of mpurities will cause a substance to melt at lower temperatures spanning a wider range.

It doesn't matter what the melting point of the additive is. If you mix in something with a higher melting point than the substance itself this property still applies. Melting points never lie.

This phenemona is called melting point depression.

Even if you don't know the literature values, you can still get a rough idea for the purity of a substance bu checking the range it melts over. If the range is 2 degrees or less you can consider it to be a pretty pure substance.

Rule of Thumb for Rough % Purity Estimates:
Melting points are more of a qualitative analytical tool and this is not a very strict correlation. This is just meant to give you a rough idea of the % purity to help you get an estimate.

First get the literature value of a substance, take the melting point of the substance, then take the top number of the range, and starting with 99.99% for every degree celcius lower the experimental value was compared to the literature value, subtract 2% from 99.99 to get a rough estimate of the sample purity.

You can also identify unknown compounds using the melting point. If you've established that the compound melts over a pretty short range, it's likely pure enough to attempt to find a likely match using published melting point values. There are a lot more melting point tricks that you can use, but this is just meant as an introductory guide.

Literature Values for Cocaine Melting Points:
Cocaine Hydrochloride: 195C
Cocaine Base: 89C

Trust me when I say you will never see a melting point anywhere close to the literature values. They're for >99.9% cocaine. Unless you manage to get a purchasing account and DEA approval to buy ACS grade cocaine from a chemical supplier like Sigma-Aldrich.

Even for the advanced clandestine labs that produce very high purity cocaine in bulk, the product ends up decomposing pretty rapidly to around 97% just from reacting with water in the air. If you ever look at bulk seizure purity distributions they always top out at 97% for that reason.


Cocaine-Specific Testing and What Values you Can Reasonably Expect to See:
The highest melting point you could conceivably ever see in a wild sample would be somewhere in the range of 189-190C, and you'd have to find the best coke possible and know what to do in order to clean it up a little like acetone washing and hotplating to remove any methzyl benzoate, etc.

Cocaine goes through a lot on the journey from being an alkaloid inside a plant in the jungle to ending up in a bag in your hands. Aside from cuts, it can contain trace impurities like other alkaloids, petroleum distillates and oils, or just dust and dirt (try dissolving a few grams of coke in water or alcohol and then shine a flashlight through it).

Realistically for street/market sample testing and rule of thumb math, you can consider a melting point of 190C = >99% purity.

The highest melting point for cocaine hydrochloride I have ever seen was just over 186C. This was from starting with a batch from RushRush, then acetone washing it twice before drying it in the oven.

True "uncut" cocaine with no adulterants should at bare minimum melt above 176C as long as the sample has been properly dried with a hotplate or oven.

High purity cocaine is also clear when it melts in the capillary.

Most cocaine you'll find on the streets and on the markets melts in the 160s and low to mid 170s.


EQUIPMENT RECOMMENDATIONS:

APPARATUS AND DIGITAL THERMOMETER
If you can afford it, I highly recommend getting an apparatus that has a digital display and built in thermometer. They're more expensive but if you're a vendor this should be what you get. The accuracy and ease of use are great. Just search for "digital melting point apparatus" on ebay. Cole-Parmer makes a good one but all of the digital ones are well made. Get an insurance plan since it's a device with a heating element.

If you're on a starter budget, I recommend looking for a mel-temp II apparatus. The thermometer should be a single input (or more) digital thermometer that supports K-type thermocouple probes. The quality of this will be the main factor in how accurate the temperature measurement is. Fluke is the golden standard for accuracy and quality, but any will do.

There are a few ebay sellers that are selling combo kits where the digital thermometer and probe come with the apparatus. These are great, and I highly recommend looking for one of these.

MELTING POINT CAPILLARIES
These are small, very thin glass tubes that you put the sample into. Search for ones that are closed at one end and open at the other. You'll se a lot with two open ends but you don't want those. Those are for people familiar with simple glass-blowing techniques.

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PROCEDURAL SECTION

PRE-TEST:

i.) Look up the expected melting point values for the substance you're going to be testing. Make sure you look for the hydrochloride salt forms. If you search for the melting points of cocaine, lidocaine, levamisole, etc you'll get the values for the base forms. Search for levamisole hydrochloride, etc. Get the values for the base and the salt if you aren't sure which you're dealing with.

ii.) Unless you got one of the higher end ones with a built in digital thermometer devices, you'll need to insert your thermometer. Insert the thermocouple probe into one of the capillary slots, or place the solid probe into the top thermometer slot. If you get one of the cheap blue mel-temps that are around $90 you'll see a yellow alcohol thermometer sticking out of it in the marketing picture. You can use partial immersion thermometers containing mercury or alcohol like in the picture, but mercury is extremely hazardous and alcohol thermometers don't cover enough of a temperature range for our purposes since they tend to top out at around 150C, so a separate digital thermometer is recommended.

iii.) You'll save a little time if you start your melting point now and let it warm up while you do the sample prep. Set it to a low value. Models without a digital termperature controller and thermometer built in will have a dial that controls the temperature. Set it to around 3 while you fill a capillary with the sample.


TESTING PROCEDURE:
(I recommend using one of the resources linked to at the end, or search up videos on how to do this procedure, so you can see how it's done)

0.) A small bit should be ground to a fine powder. The sample should be as dry as possible. If necessary, use an oven or hot plate to make sure there isn't residual moisture or methyl benzoate or it will make the sample hard to load into the capillary and lower the melting point.

1.) The sample should be ground to as fine of a powder as possible and be as dry as possible. For cocaine hydrochloride use an oven or hot plate to make sure there isn't residual moisture or methyl benzoate or it will make the sample hard to load into the capillary and lower the melting point.

2.) Load a small amount of the sample to be tested into a clean capillary tube by poking the open end into a little pile of the sample. It helps if you place the substance into something like a shotglass first. Do this until you can see that a little bit of powder has made it inside the tube. If your device uses thin capillary tubes with a .25mm diameter like most do at this point it's stuck at the top. You want it at the bottom, and you want it to be packed tightly in order to ensure accurate results.

The first thing you should try is just tapping the bottom on a hard surface. If you dried the powder properly and the situation is ideal then you'll see it start to drop to the bottom just from this. With many substances it's not so easy, so you may have to get a little creative.

Some people take the milled edge of a quarter or dime and rub it on the edge of the capillary at the top and the vibration causes the sample to loosen and drop. Others will drop it down a graduated cylinder so the closed end bounces. If all else fails you can also use a thin wire like a guitar string to help loosen the blockage.

At any rate you only need a small amount, The ideal height is around 3mm

If you use a little too much, it's not a really big deal, the range will just be artificially broad by a small amount, due to the extra time it will take for the sample to melt. In order to counteract this you can slow the rate that the apparatus is heating at. Either way, you'll still get a good idea of the melting point especially if it's a relatively pure sample.

3.) Load the capillary into the device and look through the view port, you should have a good view of the sample and it should be nicely packed with no air gaps. If you have a really nice device with a built-in camera you may see the capillary and sample on the LCD screen next to the temperature controls.

4.) If you have a device that doesn't have a built-in thermometer or pre-installed probe, take the probe from the digital thermometer and thread it down into one of the adjacent capillary holes next to the capillary with the sample. There are some photos showing k-type thermocouples inserted into the top hole where a partial immersion thermometer can go. This won't give you an accurate reading, and is not recommended.

5.) Slowly increase the temperature using the temperature controller until the sample begins to melt. Keep a close eye on the temperature display and observe the sample closely for any signs of melting. First the sample will withdraw from the sides of the tube and form a cone shape, this is called the sintering point. Past this, when you first see liquid, is the beginning of your range.

6.) Once the sample has completely melted, quickly note the temperature. This is the melting point of the sample, and with the initial number you have your range width as well.**

Often with melting points it's common to do two tests in order to save time. This is especially the case if you have an analogue device and you aren't familiar with what numbers will reach what temperatures, and even moreso if you have a sample where you aren't sure what the melting point will be.

The first test is for a rough estimate so you set the dial/set temperature to a relatively high number, so that the temperature climbs pretty quickly. This way you'll reach the melting point pretty fast and it will give you a good rough estimate for what temperature you can expect your sample to start to melt at.

The first time around, keep an eye on the sample and note the temperature around which you saw it was completely finished melting.

Then, for a more accurate reading you repeat the process but the second time around you want to allow the temperature to get to around 10-15 degrees below the temperature the sample melted at before. At this point you want to turn down the heating to where your thermometer only climbs by about 1 degree per minute.

The second time around, keep a close eye on the sample and follow the standard procedure for melting point measurement: record the temperature at which you first start to see liquid forming and then the temperature at which the sample is fully melted. This is your range.

======= RESOURCES AND LINKS: WARNING THESE ARE ALL CLEARNET! ===========
⚠️Excellent guide on melting point determination procedure that's mostly images⚠️ (I recommend you read this at some point)

It's one of the sections from "Organic Chemistry Lab Techniques" by Lisa Nichols from Butte College, hosted on on LibreTexts Chemistry.
If you want to understand more about the theory of melting points work, or learn some additional tricks you can do involving melting points, I recommend ⚠️checking out the rest of the chapter.⚠️


EXAMPLE EQUIPMENT

ENTRY LEVEL MELTING APPARATUS:
⚠️Used Mel-temp II with Cole-Parmer Thermometer: $189.99⚠️
⚠️Mel-temp II in new condition no thermometer: $179.99⚠️
⚠️Used Mel-temp II no thermometer: $179.99⚠️


DIGITAL THERMOMETERS AND PROBES:
⚠️ Used Fluke 52 II dual input digital thermometer with 2 included k-type probes: $70⚠️
⚠️ Used Fluke 52 II dual input digital thermometer with 1 included k-type probe $47⚠️
⚠️ Fluke 52 K/J Single Input Digital Thermometer Calibrated plus 1 new k-type thermocouple $85.95⚠️


HIGH QUALITY MPA's WITH BUILT-IN DIGITAL THERMOMETERS AND DISPLAYS:
⚠️Stuart SMP3 used $750⚠️
⚠️Digital Stuart SMP30 $2173.63⚠️
⚠️Used Stuart SMP50 Digital apparatus with Digital Screen: $2150⚠️
⚠️Extremely Nice, New Stuart SMP50 Digital apparatus with LCD Display and built in Camera on Capillaries: $3150⚠️


MELTING POINT CAPILLARIES:
⚠️One end open MP Capillary Pack Example 1⚠️
⚠️One end open MP Capillary Pack Example 2⚠️
⚠️One end open MP Capillary Pack Example 3⚠️