Tryptamine Turns Purple with Ehrlich Reagent

— by: earth, Sylvia, Fire, Jurek, and anonymous experts

Here’s a peek into how Erowid works with a network of drug-checking experts around the world work. Just another day at DrugsData. :]

On June 30, we published the test results for a sample of 1P-LSD blotter (dd10683), confirming the presence of 1P-LSD.

On July 12, Jurek from, a Polish harm reduction and field reagent specialist, inquired about this sample, noting that the Ehrlich reagent photo showed an unexpected purple reaction. Jurek pointed out that 1P-LSD isn’t known to result in a purple color in the presence of Ehrlich reagent, helping to differentiate it from LSD-25, which does cause a purple color change with Ehrlich reagent.

We discussed this with our lab and learned that there was a small GC peak they had not initially reported in the results: inactive salts and inks on blotter do not always get reported due to DEA-imposed limitations.

Given the unexpected Ehrlich reaction, we published the spectrum for the unidentified chemical and added it to the results as a second chemical present in the sample.

A chemist in the Erowid Expert Network identified the unknown chemical as tryptamine, so we ordered a lab standard for tryptamine and found that it was a perfect match via GC/MS.

Further, DrugsData’s lab did side-by-side comparison in a ceramic well plate of lab standards for 1B-LSD, 1P-LSD, and LSD-25. The third of four wells is the ‘blank’ labeled MeCN (acetonitrile) which was the solvent used to dissolve each of the ergoloid standards (1B-LSD, 1P-LSD, LSD-25). Ehrlich reagent was applied to each, demonstrating that neither 1B-LSD nor 1P-LSD turn purple with Ehrlich, where LSD-25 does.

So the mystery of the the unexpected Ehlrich reaction for this 1P-LSD blotter is resolved, but the reason why someone added tryptamine to 1P-LSD blotter is still open. We all guess the goal was to be able to sell the 1P-LSD blotter as LSD-25, and that adding tryptamine to the 1P-LSD will result in reagent reactions consistent with LSD-25.

This is the first time Erowid has seen this type of adulteration of non-LSD ergoloids with the chemical tryptamine.

The image below is a link to a video of the reagent test:

Then, a photo of lab-grade tryptamine reacted with Ehrlich. A strong purple color:

Evolving the Approach to Reagents and LSD Gel Tabs

Drug checking is a complex and evolving area of research. In EcstasyData’s effort to show accurate findings to the public, we’re working with the unique conditions of each sample. Most recently, the lab has innovated in its handling of LSD gel tabs.

There’s LSD, and then there’s gel tab LSD

Since 2014, the year EcstasyData’s lab developed its procedure for a practical and time-efficient way to identify LSD using GC/MS, gel tabs have been infrequently submitted for analysis. The majority of LSD samples submitted to our lab use blotter paper as the carrier (the lab requires that all samples be dry, no liquid samples are accepted without prior arrangement), though it is Erowid Center’s opinion that most of the LSD currently in distribution is in liquid/solution form.

Prior to 2017, the rare gel tab sample would get refused by the lab’s main chemist, who at the time did not feel confident that these samples could be adequately analyzed for the presence of LSD.

Besides analyzing each sample using GC/MS, which is the analytical method EcstasyData uses to detect the presence of chemicals, the lab also tests samples with reagents. Reagent testing adds descriptive data that adds to the collective knowledge base for drug checking. (Reagent testing can’t positively identify chemicals.)

It turns out that gelatin as a medium makes reagent testing more complicated; the pH conditions required to dissolve the gel affect the reagent even when dried. For this reason, gel tabs do not react normally to field reagents such as Marquis or Ehrlich.

De-weirding reagent colors

Between 2017 and November 2018, five gel tab samples were analyzed by EcstasyData, with GC/MS showing that four of them were LSD. The Ehrlich reagent reactions for these four samples were atypical. LSD normally reacts to Ehrlich reagent by turning purple, but when Ehrlich was applied directly to the dry (or even wet) gelatin in these cases, the results were mixed, turning brown or brown-purple, or other atypical reactions.

The lab began working with the special needs of these samples, and in November 2018, they developed a sample-preparation procedure that allows Ehrlich reagent to show a typical positive (rule-in) response to LSD in gel tabs.

New process for gelatin

We are publishing Erowid Center / DDL’s new procedure that is being used to process dry-gelatin-tab dose units, for the historical record, and so that others can duplicate it and critique it.

The following is the procedure that was used to produce the photo shown for Sample 6813, the first sample treated in this way:

  1. Gel medium placed in small amount of water.
  2. Basify gel-water mixture with NaOH.
  3. Gel medium fully dissolves.
  4. Solvent (ethyl acetate) added to gel-water mixture.
  5. Solvent separated off and dropped onto ceramic well plate.
  6. Unheated evaporation of solvent until dry.
  7. Drop field reagents into wells, photograph.

This is the process that the lab will use to prep future gel tab samples for reagents. It will be interesting to see how other samples respond to it, and whether further tinkering with the process will be required.

Marquis and LSD: Is color change visible?

Short Summary: Marquis, Mecke, Mandelin, and Simons are not reliable tools for confirming or disproving the presence of LSD in blotter, liquid, gel, or tablet forms.

 Figure 1 Confirmed LSD blotter produces little or no reaction to Marquis, Mecke, and Mendelin when tested on white porcelain.
Figure 1 Confirmed LSD blotter produces little or no reaction to Marquis, Mecke, and Mendelin when tested on white porcelain.

Long Version: We get asked a lot about how specific drugs react to the various drug-detection field tests like Marquis, Mecke, Mandelin, Simons, Robadope, Ehrlich’s, etc. In most cases, it’s a matter of getting some of the pure target compound, a fresh set of reagents, and doing a little testing, photographing, and documentation..

However, with drugs active below 1mg, such as LSD, this may not be so simple. Because the amount of target compound is often very small, the reactions can be altered, slowed, or blocked by tiny amounts of other substances present. In the case of LSD blotter paper, where the amount of LSD on a 1/4″ square (6mmx6mm) is usually at or below 100 micrograms, the paper and the ink on the paper are far more likely to be the cause of a color change than the LSD itself. With liquid LSD, the alcohol carrier can dilute the response enough that no color change is visible. Thus, a color change or the lack of color change can be due to the form in which the substance is being tested.

LSD is said to create an olive green or black reaction with a Marquis reagent test. Organizations that sell reagent tests such as Dancesafe and Bunk Police report that LSD has an olive-black reaction with a Marquis test. This may be based upon sources such as this Department of Justice article stating that LSD causes an “Olive black” result. [ Fatah A. “Color Test Reagents/Kits for Preliminary Identification of Drugs of Abuse” (2000) ].

Figure 2 LSD sample confirmed by GC/MS produces no response to Marquis, Mecke, or Mandelin reagents.  Black squares shown to illustrate blotter location do not indicate a “black” color reaction to these tests.
Figure 2 LSD sample confirmed by GC/MS produces no response to Marquis, Mecke, or Mandelin reagents. Black squares shown to illustrate blotter location do not indicate a “black” color reaction to these tests.

However, the results of our own lab’s field tests on samples confirmed to contain LSD using GC/MS show varying responses to Marquis and other field tests. When tested with a Marquis reagent, most of these samples showed no reaction or only a very slight reaction and none produced an olive green or black reaction. For examples of these test results see Figure 1 and Figure 2. Furthermore, the blotter paper itself—not the LSD—may be causing these slight reactions.

You can see a list of numerous LSD samples on EcstasyData along with their field test color changes here:

Despite claims that LSD produces an olive green or black reaction to Marquis, evidence collected and published through EcstasyData does not support this. Furthermore, a 1979 paper by by Johns et al is consistent with these EcstasyData results. The researchers tested a wide variety of drugs from that era with nine different reagent tests, including Marquis and Ehrlich (Table 1). This paper reports that LSD only reacts with Ehrlich and not with any of the other reagents. Interestingly, the researchers used dry LSD from Sandoz Laboratories. Other publications claiming that LSD produces olive green or black reactions to Marquis do not report the source or form (i.e. liquid, crystal, or blotter) of the LSD tested. The results of the Johns et al., study suggests that confirmed pure crystal LSD has no reaction with a Marquis test. Below is a summary of the results:

Compound Reagent test Color reaction Testing surface
LSD Marquis no reaction Porcelain
LSD Mecke no reaction Porcelain
LSD Madelin no reaction Porcelain
LSD Cobalt thiocyanate no reaction Porcelain
LSD Dille-Koppanyi no reaction Porcelain
LSD Ehrlich purple Porcelain
LSD Froehde no reaction Porcelain
LSD Sulfuric acid no reaction Porcelain
LSD Nitric acid no reaction Porcelain

Although other sources say that LSD causes an olive-black reaction with a Marquis reagent test, this study, along with the EcstasyData results, suggests that LSD may not cause an olive-black reaction with a Marquis test—at least not on blotter paper in the amounts it is commonly sold. Based on this evidence, the Marquis is not a reliable for test for LSD. On the other hand, the Ehrlich may be an alternative test for this purpose based on the findings published by Johns et al. The Ehrlich reagent produces a color change when LSD or another indole is present. However, like all reagent tests, an Ehrlich is not a confirming test, it is just another in a wide array of rule in / rule out tests that can help confirm or deny the presence of LSD in a given sample.

Thanks to W and Shaolin at the DMT Nexus for their work on this issue.

Trying New Spot Plate Methods

We’ve been trying to come up with better ways to do and photograph the spot plate reagent field tests for the variety of chemicals. Both the ones sold as ecstasy/molly and the wide variety of substances and pharmaceuticals that people send in for analysis.

The solid ceramic spot plate we’ve been using for the last 15 years makes it so the colors are hard to see in darker reactions.

So we’ve been hunting down translucent glass plates but haven’t found many. We would like one that we can use AND recommend to Erowid visitors around the world they can buy for a reasonable price.

Here are some photos comparing the translucent spot plate with the opaque one.

Old spot plate:

lightbox test
A drop of marquis reagent on some random aminated oxygenated phenethylamine-ish chemical.
lightbox test
A drop of marquis reagent on some random aminated oxygenated phenethylamine-ish chemical.

Perhaps the most interesting is that all three of these color spots are Marquis + the same chemical. The right hand spot is the oldest (over an hour since drop), the left one is maybe 30+ minutes, and the top middle one was dropped within a minute. This chemical starts off as a grey purple, to a very dark nice blue purple, then goes to a dark blue, then winds up in this greenish gray color.

lightbox test
A drop of marquis reagent on some random aminated oxygenated phenethylamine-ish chemical.