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Chimera

Genetic Resource Management
Veteran
....regarding terpenol, all terpiniods are natuarlly derived from terpenol...

terpenoids NOT terpinoids?

terpenol ?! Do you mean terpineol? terpinolene?

Terpenes are derived from isoprene units.. IPP, DMAP... can you show me just a single reference anywhere that says all terpenoids are derived from "terpenol"?

The fact that you aren't clear of the major biosynthetic precursors to your molecules of interest (sterols) is a red flag. On top of that you can't seemingly properly spell terpenoids...

I hate to call BS on a new member trying to contribute, but man your information is so full of holes... you are either really new to this, or have no clue what you are taking about... just calling a spade a spade.

-Chimera
 

VagPuncher

Balls Deep!!
ICMag Donor
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tumblr_ljh0puClWT1qfkt17.gif
 

med-man

The TRUMP of SKUNK: making skunk loud again!
Boutique Breeder
ICMag Donor
Veteran
terpenoids NOT terpinoids?

terpenol ?! Do you mean terpineol? terpinolene?

Terpenes are derived from isoprene units.. IPP, DMAP... can you show me just a single reference anywhere that says all terpenoids are derived from "terpenol"?

The fact that you aren't clear of the major biosynthetic precursors to your molecules of interest (sterols) is a red flag. On top of that you can't seemingly properly spell terpenoids...

I hate to call BS on a new member trying to contribute, but man your information is so full of holes... you are either really new to this, or have no clue what you are taking about... just calling a spade a spade.

-Chimera


hey chime,

i have been trying to get O.C. to contact you for info if he needs.

i think he is very sensitive to the childish rants most trolls have given him, respectfully.

i will try to get him out of his shell and would really like to see what either of you have to talk about.

at the end of the day, his career is an organic chemist, and i think you guys would like each other in and out of ic either way

med-man
 
do you think you are the american rapper 2pac by chance lol hahahaha

med-man

The dude's got some funky iran weed. Wouldn't be so bad if iran was seriously in the game. Their seed originated from outside the country like everyone else's outside the Himalayas.

Med-Man's strains are superior to storms, & he's jealous about it too.
 

RasG

New member
These new registrees are LOL, everyone knows so much about medman! Big ups guys lol

:laughing: yep we have a expert in you...look at how many posts you have....wow...lol and love how you troll a forum you have no interest in. lol guys lol *sarcasm
 

RasG

New member
These new registrees are LOL, everyone knows so much about medman! Big ups guys lol

Check that lip, galactic knows plenty

yes mam, plenty of knowledge was shared in his post...i am trying to keep positive but with clowna$$ posts by veteran trolls with more posts/supposed knowledge then me distracting from a interesting topic on terpenoids and their effect on the high...shantibaba of mr nice seeds has wrote articles on this topic. I would like to read and learn more on the subject from chimera...
 

Organic Chemist

New member
Chimera,

Thank you for all your information.

You are definitely correct regarding the overall CBD methodolgy of quantifying peak on my chromatogram.

I use ASTA protocol for essential oil extraction simply because that is what is available to me and a method I have been using for 10 years. A collegue who is a professor at Temple University in Philadelphia advised that ASTA extraction methodolgy is the process for extracting the organic layer from Cannabis.

once I extract the organic layer and derivitise it, I add 200 mg to 20 ml of ethyl acetate, remove a 1 ml aliquot and inject into the GC.

I am aware that my CBD results may be skewed as I have never tested for . It was suggested to me that CBN and CBD levels are calculated using respose ratios however this is not something i have much expereince in.

Any help I can get from you regarding CBN and CBD calculation would be greatly appreciated.

As for tetrahydrocannbinol, i can assure you my extraction and GC methods are accurate.
I obviously use a non polar column
Retention time is usually around 12-14 minutes.
I do have access to an HPLC however was advised that a GC is better for THC because the stationary phase temperature are more favourable

I am always willing to learn new methods. I in no way pride myself as an expert in Cannabis, however I am extremely experienced in organic chemistry and any of your friends would advise that amino acids and fatty acids of Cannabis is the new wave in Cannibis research.

I thank you for your comments and hope to have insightful dialogue in the future.
 

Chimera

Genetic Resource Management
Veteran
OC, your methodology is extremely flawed in multiple regards, and is obviously not a validated protocol. All of your results are not only suspect, they are simply incorrect and not reliable. Your sampling methodology alone will yield an incredible variation in the results... remember we are trying to accurately represent what is actually in the flowers, and at what concentrations, not just throw some numbers on a sample for marketing purposes.. correct?

Saying the ASTA protocol is all you have access to is beyond ludicrous, you are obviously connected to the internet by your ability to post here, so I have a difficult time believing you can't access the dozens upon dozens of protocols available in published articles, available for free online.

Qualitatively, you can't even separate the different cannabinoid peaks if your THC elution times are in the order of 12-14 minutes.... and quantitatively your sampling protocol alone leads to a huge potential for human error, issues with repeatability, etc. Essentially, you may as well be just making some numbers up because if you bring the same flowers to a lab that is running a validated protocol specific to cannabinoids, your numbers will be well off the mark.

I would be happy to help you guys get your lab protocol up to speed and validated; our consulting fees are very reasonable.

-Chimera
 

med-man

The TRUMP of SKUNK: making skunk loud again!
Boutique Breeder
ICMag Donor
Veteran
organic chemist

read this:

How to test THC the honest way - Tutorial
There are many claims out there of strains having very high THC levels. After speaking with a scientist at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), I have been told that the only consistent and honest way to measure THC, CBD, and CBN is to use a test using Liquid Gas Chromatography. Here is some info on that process. I have sourced this from Wikipedia.

Gas-liquid chromatography (GLC), or simply gas chromatography (GC), is a type of chromatography in which the mobile phase is a carrier gas, usually an inert gas such as helium or an unreactive gas such as nitrogen, and the stationary phase is a microscopic layer of liquid or polymer on an inert solid support, inside glass or metal tubing, called a column. The instrument used to perform gas chromatographic separations is called a gas chromatograph (also: aerograph, gas separator).

Gas Chromatography is different from other forms of chromatography (HPLC, TLC, etc.) because the solutions travel through the column in a gas state. The interactions of these gaseous analytes with the walls of the column (coated by different stationary phases) causes different compounds to elute at different times called retention time. The comparsion of these retention times is the analytical power to GC. This makes it very similar to HPLC.
Contents
[hide]

* 1 History
* 2 GC analysis
* 3 Physical components
o 3.1 Autosamplers
o 3.2 Inlets
o 3.3 Columns
o 3.4 Detectors
* 4 Methods
o 4.1 Carrier gas selection and flow rates
o 4.2 Inlet types and flow rates
o 4.3 Sample size and injection technique
+ 4.3.1 Sample injection
o 4.4 Column selection
o 4.5 Column temperature and temperature program
* 5 Data reduction and analysis
* 6 Application
* 7 GCs in popular culture
* 8 See also
* 9 References
* 10 External links

[edit] History

Chromatography dates to 1903 in the work of the Russian scientist, Mikhail Semenovich Tswett. German graduate student Fritz Prior developed solid state gas chromatography in 1947. Archer John Porter Martin, who was awarded the Nobel Prize for his work in developing liquid-liquid (1941) and paper (1944) chromatography, laid the foundation for the development of gas chromatography and later produced liquid-gas chromatography (1950).

[edit] GC analysis

A gas chromatograph is a chemical analysis instrument for separating chemicals in a complex sample. A gas chromatograph uses a flow-through narrow tube known as the column, through which different chemical constituents of a sample pass in a gas stream (carrier gas, mobile phase) at different rates depending on their various chemical and physical properties and their interaction with a specific column filling, called the stationary phase. As the chemicals exit the end of the column, they are detected and identified electronically. The function of the stationary phase in the column is to separate different components, causing each one to exit the column at a different time (retention time). Other parameters that can be used to alter the order or time of retention are the carrier gas flow rate, and the temperature.

In a GC analysis, a known volume of gaseous or liquid analyte is injected into the "entrance" (head) of the column, usually using a microsyringe (or, solid phase microextraction fibers, or a gas source switching system). As the carrier gas sweeps the analyte molecules through the column, this motion is inhibited by the adsorption of the analyte molecules either onto the column walls or onto packing materials in the column. The rate at which the molecules progress along the column depends on the strength of adsorption, which in turn depends on the type of molecule and on the stationary phase materials. Since each type of molecule has a different rate of progression, the various components of the analyte mixture are separated as they progress along the column and reach the end of the column at different times (retention time). A detector is used to monitor the outlet stream from the column; thus, the time at which each component reaches the outlet and the amount of that component can be determined. Generally, substances are identified (qualitatively) by the order in which they emerge (elute) from the column and by the retention time of the analyte in the column.

[edit] Physical components

[edit] Autosamplers

The autosampler provides the means to introduce automatically a sample into the inlets. Manual insertion of the sample is possible but is no longer common. Automatic insertion provides better reproducibility and time-optimization.

Different kinds of autosamplers exist. Autosamplers can be classified in relation to sample capacity (auto-injectors VS autosamplers, where auto-injectors can work a small number of samples), to robotic technologies (XYZ robot VS rotating/SCARA-robot – the most common), or to analysis:

* Liquid
* Static head-space by syringe technology
* Dynamic head-space by transfer-line technology
* SPME

Traditionally autosampler manufactures are different from GC manufactures and currently no GC manufacture offers a complete range of autosamplers. Historically, the countries most active in autosampler technology development are the United States, Italy, and Switzerland.

[edit] Inlets

The column inlet (or injector) provides the means to introduce a sample into a continuous flow of carrier gas. The inlet is a piece of hardware attached to the column head.

Common inlet types are:

* S/SL (Split/Splitless) injector; a sample is introduced into a heated small chamber via a syringe through a septum - the heat facilitates volatilization of the sample and sample matrix. The carrier gas then either sweeps the entirety (splitless mode) or a portion (split mode) of the sample into the column. In split mode, a part of the sample/carrier gas mixture in the injection chamber is exhausted through the split vent.
* On-column inlet; the sample is here introduced in its entirety without heat.
* PTV injector; Temperature-programmed sample introduction was first described by Vogt in 1979. Originally Vogt developed the technique as a method for the introduction of large sample volumes (up to 250 µL) in capillary GC. Vogt introduced the sample into the liner at a controlled injection rate. The temperature of the liner was chosen slightly below the boiling point of the solvent. The low-boiling solvent was continuously evaporated and vented through the split line. Based on this technique, Poy developed the Programmed Temperature Vaporising injector; PTV. By introducing the sample at a low initial liner temperature many of the disadvantages of the classic hot injection techniques could be circumvented.
* Gas source inlet or gas switching valve; gaseous samples in collection bottles are connected to what is most commonly a six-port switching valve. The carrier gas flow is not interrupted while a sample can be expanded into a previously evacuated sample loop. Upon switching, the contents of the sample loop are inserted into the carrier gas stream.
* P/T (Purge-and-Trap) system; An inert gas is bubbled through an aqueous sample causing insoluble volatile chemicals to be purged from the matrix. The volatiles are 'trapped' on an absorbent column (known as a trap or concentrator) at ambient temperature. The trap is then heated and the volatiles are directed into the carrier gas stream. Samples requiring preconcentration or purification can be introduced via such a system, usually hooked up to the S/SL port.
* SPME (solid phase microextraction) offers a convenient, low-cost alternative to P/T systems with the versatility of a syringe and simple use of the S/SL port.

[edit] Columns

Two types of columns are used in GC:

* Packed columns are 1.5 - 10 m in length and have an internal diameter of 2 - 4 mm. The tubing is usually made of stainless steel or glass and contains a packing of finely divided, inert, solid support material (eg. diatomaceous earth) that is coated with a liquid or solid stationary phase. The nature of the coating material determines what type of materials will be most strongly adsorbed. Thus numerous columns are available that are designed to separate specific types of compounds.
* Capillary columns have a very small internal diameter, on the order of a few tenths of millimeters, and lengths between 25-60 meters are common. The inner column walls are coated with the active materials (WCOT columns), some columns are quasi solid filled with many parallel micropores (PLOT columns). Most capillary columns are made of fused-silica with a polyimide outer coating. These columns are flexible, so a very long column can be wound into a small coil.
* New developments are sought where stationary phase incompatibilities lead to geometric solutions of parallel columns within one column. Among these new developments are:
o Internally heated microFAST columns, where two columns, an internal heating wire and a temperature sensor are combined within a common column sheath (microFAST);
o Micropacked columns (1/16" OD) are column-in-column packed columns where the outer column space has a packing different from the inner column space, thus providing the separation behaviour of two columns in one. They can be easily fit to inlets and detectors of a capillary column instrument.

The temperature-dependence of molecular adsorption and of the rate of progression along the column necessitates a careful control of the column temperature to within a few tenths of a degree for precise work. Reducing the temperature produces the greatest level of separation, but can result in very long elution times. For some cases temperature is ramped either continuously or in steps to provide the desired separation. This is referred to as a temperature program. Electronic pressure control can also be used to modify flow rate during the analysis, aiding in faster run times while keeping acceptable levels of separation.

The choice of carrier gas (mobile phase) is important, with hydrogen being the most efficient and providing the best separation. However, helium has a larger range of flowrates that are comparable to hydrogen in efficiency, with the added advantage that helium is non-flammable, and works with a greater number of detectors. Therefore, helium is the most common carrier gas used.

[edit] Detectors

A number of detectors are used in gas chromatography. The most common are the flame ionization detector (FID) and the thermal conductivity detector (TCD). Both are sensitive to a wide range of components, and both work over a wide range of concentrations. While TCDs are essentially universal and can be used to detect any component other than the carrier gas (as long as their thermal conductivities are different than that of the carrier gas, at detector temperature), FIDs are sensitive primarily to hydrocarbons, and are more sensitive to them than TCD. However, an FID cannot detect water. Both detectors are also quite robust. Since TCD is non-destructive, it can be operated in-series before an FID (destructive), thus providing complementary detection of the same eluents.

Other detectors are sensitive only to specific types of substances, or work well only in narrower ranges of concentrations. They include:

* discharge ionization detector (DID)
* electron capture detector (ECD)
* flame photometric detector (FPD)
* Hall electrolytic conductivity detector (ElCD)
* helium ionization detector (HID)
* nitrogen phosphorus detector (NPD)
* mass selective detector (MSD)
* photo-ionization detector (PID)
* pulsed discharge ionization detector (PDD)
* thermal energy analyzer (TEA)

Some gas chromatographs are connected to a mass spectrometer which acts as the detector. The combination is known as GC-MS. Some GC-MS are connected to an NMR spectrometer which acts as a back up detector. This combination is known as GC-MS-NMR. Some GC-MS-NMR are connected to an infrared spectrophotometer which acts as a back up detector. This combination is known as GC-MS-NMR-IR. It must, however, be stressed this is very rare as most analyses needed can be concluded via purely GC-MS.

[edit] Methods

The method is the collection of conditions in which the GC operates for a given analysis. Method development is the process of determining what conditions are adequate and/or ideal for the analysis required.

Conditions which can be varied to accommodate a required analysis include inlet temperature, detector temperature, column temperature and temperature program, carrier gas and carrier gas flow rates, the column's stationary phase, diameter and length, inlet type and flow rates, sample size and injection technique. Depending on the detector(s) (see below) installed on the GC, there may be a number of detector conditions that can also be varied. Some GCs also include valves which can change the route of sample and carrier flow, and the timing of the turning of these valves can be important to method development.

[edit] Carrier gas selection and flow rates

Typical carrier gases include helium, nitrogen, argon, hydrogen and air. Which gas to use is usually determined by the detector being used, for example, a DID requires helium as the carrier gas. When analyzing gas samples, however, the carrier is sometimes selected based on the sample's matrix, for example, when analyzing a mixture in argon, an argon carrier is preferred, because the argon in the sample does not show up on the chromatogram. Safety and availability can also influence carrier selection, for example, hydrogen is flammable, and high-purity helium can be difficult to obtain in some areas of the world. (See: Helium--occurrence and production.)

The purity of the carrier gas is also frequently determined by the detector, though the level of sensitivity needed can also play a significant role. Typically, purities of 99.995% or higher are used. Trade names for typical purities include "Zero Grade," "Ultra-High Purity (UHP) Grade," "4.5 Grade" and "5.0 Grade."

The carrier gas flow rate affects the analysis in the same way that temperature does (see above). The higher the flow rate the faster the analysis, but the lower the separation between analytes. Selecting the flow rate is therefore the same compromise between the level of separation and length of analysis as selecting the column temperature.

With GCs made before the 1990s, carrier flow rate was controlled indirectly by controlling the carrier inlet pressure, or "column head pressure." The actual flow rate was measured at the outlet of the column or the detector with an electronic flow meter, or a bubble flow meter, and could be an involved, time consuming, and frustrating process. The pressure setting was not able to be varied during the run, and thus the flow was essentially constant during the analysis.

Many modern GCs, however, electronically measure the flow rate, and electronically control the carrier gas pressure to set the flow rate. Consequently, carrier pressures and flow rates can be adjusted during the run, creating pressure/flow programs similar to temperature programs.

[edit] Inlet types and flow rates

The choice of inlet type and injection technique depends on if the sample is in liquid, gas, adsorbed, or solid form, and on whether a solvent matrix is present that has to be vaporized. Dissolved samples can be introduced directly onto the column via a COC injector, if the conditions are well known; if a solvent matrix has to be vaporized and partially removed, a S/SL injector is used (most common injection technique); gaseous samples (e.g., air cylinders) are usually injected using a gas switching valve system; adsorbed samples (e.g., on adsorbent tubes) are introduced using either an external (on-line or off-line) desorption apparatus such as a purge-and-trap system, or are desorbed in the S/SL injector (SPME applications).

[edit] Sample size and injection technique

[edit] Sample injection

The real chromatographic analysis starts with the introduction of the sample onto the column. The development of capillary gas chromatography resulted in many practical problems with the injection technique. The technique of on-column injection, often used with packed columns, is usually not possible with capillary columns. The injection system, in the capillary gas chromatograph, should fulfil the following two requirements:

1. The amount injected should not overload the column.
2. The width of the injected plug should be small compared to the spreading due to the chromatographic process. Failure to comply with this requirement will reduce the separation capability of the column. As a general rule, the volume injected, Vinj, and the volume of the detecor cell, Vdet, should be about 1/10 of the volume occupied by the portion of sample containing the molecules of interest (analytes) when they exit the column.

Some general requirements, which a good injection technique should fulfill, are:

* It should be possible to obtain the column’s optimum separation efficiency.
* It should allow accurate and reproducible injections of small amounts of representative samples.
* It should induce no change in sample composition. It should not exhibit discrimination based on differences in boiling point, polarity, concentration or thermal/catalytic stability.
* It should be applicable for trace analysis as well as for undiluted samples.


Please help improve this article or section by expanding it.
Further information might be found on the talk page or at requests for expansion. (February 2007)

[edit] Column selection
Please help improve this article or section by expanding it.
Further information might be found on the talk page or at requests for expansion. (February 2007)

[edit] Column temperature and temperature program

The column(s) in a GC are contained in an oven, the temperature of which is precisely controlled electronically. (When discussing the "temperature of the column," an analyst is technically referring to the temperature of the column oven. The distinction, however, is not important and will not subsequently be made in this article.)

The rate at which a sample passes through the column is directly proportional to the temperature of the column. The higher the column temperature, the faster the sample moves through the column. However, the faster a sample moves through the column, the less it interacts with the stationary phase, and the less the analytes are separated.

In general, the column temperature is selected to compromise between the length of the analysis and the level of separation.

A method which holds the column at the same temperature for the entire analysis is called "isothermal." Most methods, however, increase the column temperature during the analysis, the initial temperature, rate of temperature increase (the temperature "ramp") and final temperature is called the "temperature program."

A temperature program allows analytes that elute early in the analysis to separate adequately, while shortening the time it takes for late-eluting analytes to pass through the column.

[edit] Data reduction and analysis

Qualitative analysis:

Generally chromatographic data is presented as a graph of detector response (y-axis) against retention time (x-axis). This provides a spectrum of peaks for a sample representing the analytes present in a sample eluting from the column at different times. Retention time can be used to identify analytes if the method conditions are constant. Also, the pattern of peaks will be constant for a sample under constant conditions and can identify complex mixtures of analytes. In most modern applications however the GC is connected to a mass spectrometer or similar detector that is capable of identifying the analytes represented by the peaks.

Quantitive analysis:

The area under a peak is proportional to the amount of analyte present. By calculating the area of the peak using the mathematical function of integration, the concentration of an analyte in the original sample can be determined. Concentration can be calculated using a calibration curve created by finding the response for a series of concentrations of analyte, or by determining the relative response factor of an analyte. The relative response factor is the expected ratio of an analyte to an internal standard (or external standard) and is calculated by finding the response of a known amount of analyte and a constant amount of internal standard (a chemical added to the sample at a constant concentration, with a distinct retention time to the analyte).

In most modern GC-MS systems, computer software is used to draw and integrate peaks, and match MS spectra to library spectra.

[edit] Application

In general, substances that vaporize below ca. 300 °C (and therefore are stable up to that temperature) can be measured quantitatively. The samples are also required to be salt-free; they should not contain ions. Very minute amounts of a substance can be measured, but it is often required that the sample must be measured in comparison to a sample containing the pure, suspected substance.

Various temperature programs can be used to make the readings more meaningful; for example to differentiate between substances that behave similarly during the GC process.

Professionals working with GC analyze the content of a chemical product, for example in assuring the quality of products in the chemical industry; or measuring toxic substances in soil, air or water. GC is very accurate if used properly and can measure picomoles of a substance in a 1 ml liquid sample, or parts-per-billion concentrations in gaseous samples.

In practical courses at colleges, students sometimes get acquainted to the GC by studying the contents of Lavender oil or measuring the ethylene that is secreted by Nicotiana benthamiana plants after artificially injuring their leaves. These GC analyses hydrocarbons (C2-C40+). In a typical experiment, a packed column is used to separate the light gases, which are then detected with a TCD. The hydrocarbons are separated using a capillary column and detected with an FID. A complication with light gas analyses that include H2 is that He, which is the most common and most sensitive inert carrier (sensitivity is proportional to molecular mass) has an almost identical thermal conductivity to hydrogen (it is the difference in thermal conductivity between two separate filaments in a Wheatstone Bridge type arrangement that shows when a component has been eluted). For this reason, dual TCD instruments are used with a separate channel for hydrogen that uses nitrogen as a carrier are common. Argon is often used when analysing gas phase chemistry reactions such as F-T synthesis so that a single carrier gas can be used rather than 2 separate ones. The sensitivity is less but this is a tradeoff for simplicity in the gas supply.

[edit] GCs in popular culture

Movies, books and TV shows tend to misrepresent the capabilities of gas chromatography and the work done with these instruments.

In the U.S. TV show CSI, for example, GCs are used to rapidly identify unknown samples. "This is gasoline bought at a Chevron station in the past two weeks," the analyst will say fifteen minutes after receiving the sample.

In fact, a typical GC analysis takes much more time; sometimes a single sample must be run more than an hour according to the chosen program; and even more time is needed to "heat out" the column so it is free from the first sample and can be used for the next. Equally, several runs are needed to confirm the results of a study - a GC analysis of a single sample may simply yield a result per chance (see statistical significance).

Also, GC does not positively identify most samples; and not all substances in a sample will necessarily be detected. All a GC truly tells you is at which relative time a component eluted from the column and that the detector was sensitive to it. To make results meaningful, analysts need to know which components at which concentrations are to be expected; and even then a small amount of a substance can hide itself behind a substance having both a higher concentration and the same relative elution time. Last but not least it is often needed to check the results of the sample against a GC analysis of a reference sample containing only the suspected substance.

A GC-MS can remove much of this ambiguity, since the mass spectrometer will identify the component's molecular weight. But this still takes time and skill to do properly.

Similarly, most GC analyses are not push-button operations. You cannot simply drop a sample vial into an auto-sampler's tray, push a button and have a computer tell you everything you need to know about the sample. According to the substances one expects to find the operating program must be carefully chosen.

A push-button operation can exist for running similar samples repeatedly, such as in a chemical production environment or for comparing 20 samples from the same experiment to calculate the mean content of the same substance. However, for the kind of investigative work portrayed in books, movies and TV shows this is clearly not the case.

med-man
 

med-man

The TRUMP of SKUNK: making skunk loud again!
Boutique Breeder
ICMag Donor
Veteran
lol people are very very funny.

so i have 2 sources testing my bud from my tables consistently at an average of 20%.

and everyone is flawed?

i have a oil nerd who tested one of my head-band samples at 27.5% bud and all. i guess these rookies that just know what they are doing?

i would say equal "flaw evidence" is necessary to debunk all the actual tests that have been going on

i will be using my chemist for all testing my labels when med-man brand "weed" goes commercial people can buy it with registered passcodes, and they can post their unbias results

med-man
 
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