Process for drug detection

The invention provides a process for the presumptive identification of cocaine or heroin street drug comprising applying to a sample of the suspected drug a reagent which gives a characteristic color reaction in the presence of trace amounts of organic bases or acetic acid. The invention also provides a prepacked screening kit for illicit cocaine and heroin street drug if present, comprising a reagent which gives a characteristic color reaction in the presence of the trace amounts of organic bases or acetic acid in said illicit substances.

The present invention relates to a process and test kit for the presumptive 
identification of cocaine and heroin (diacytylmorphine) street drug. 
As will be realized, on numerous occasions a police officer has to 
determine whether or not a suspected material contains heroin, cocaine or 
"crack" and thus quickly establish probable cause. 
Often, the laboratory is closed, or many miles away, and he has no way of 
making this determination. A test kit can help an officer detect the 
presence of such drugs or alternatively to determine that a tested sample 
definitely isn't one of said drugs. 
The quickest test known for drug detection is a color test in which the 
response of the drugs to a specific reagent makes it possible to assign 
the drug to one or more classes. 
In order to obtain sufficient evidence to detain a suspected drug peddler 
or drug user, chemical spot test kits have been commercially developed and 
are used by many law enforcement agencies for the detection of narcotics 
and drugs of abuse. 
Most of the commerical test kits for the identification of heroin are based 
on the famous Marquis sulfuric acid-formaldehyde reagent which gives a 
purple violet characteristic color with morphinan structures but not only 
with morphinan structures. 
Clark, "Isolation and Identification of Drugs" Pharmaceutical Press (1969) 
lists some 46 drugs that all respond in the same way to Marquis reagent. 
Furthermore, Marquis reagent gives other colors with hundreds of drugs. It 
is thus apparent that this single color producing reagent cannot really 
serve for the field identification of drugs, because of the possibility of 
giving a false positive with other substances of similar structure or 
similar response characteristics. 
The weakness of this single specific reagent test has led to the 
development of various combination tests which are intended to be used 
together in a manner which seeks to screen out the false positives and 
make possible a firm identification of heroin. 
In U.S. Pat. No. 4,104,027, an impedimental flow-chart is described to 
identify heroin, suggesting combination of Marquis and Mandelin or Nitric 
Acid tests. This patent has two disadvantages: 
1. It still lacks specificity; 
2. Corrosive and harmful liquids such as concentrated sulfuric acid, nitric 
acid and formaldehyde, are dangerous and impedimental for the user. 
In U.S. Pat. No. 3,955,926 there is described a process for the detection 
of narcotics wherein heroin is detected with a multi-component reagent 
comprising a solution of benzylamine and iodic acid in dilute acid, and an 
absorbent support impregnated with ferric chloride, an alkali tartarate 
and an alkali carbonate. This test however is not specific enough for 
presumptive identification of heroin. 
Similarly most of the commercial test kits for the presumptive 
identification of cocaine are based on contacting cocaine and its salts 
with cobalt thiocyanate solutions which results in the formation of a 
relatively water insoluble turquoise complex. 
The relative simplicity of the cobalt thiocyanate test made its use 
feasible outside the laboratory and created a demand for a variation with 
increased specifity. 
The standard Scott Test (L. J. Scott, Specific Field Test for Cocaine, 
Microgram VI, 179(1973), used by the customs service, is based on using 
test tubes in three stages: 
A. Using cobalt thiocyanate reagent in a 1:1 water:glycerine solution that 
forms the characteristic blue precipitate with cocaine. In this stage, 
there are still four drugs that will react with the same color reaction as 
cocaine: 
(1) Phencyclidine (PCP); 
(2) Dibucaine; 
(3) Butacaine; 
(4) Methapyrilene. 
The following two stages exclude these four drugs. 
B. Addition of concentrated hydrochloric acid to form a clear pink 
solution. 
C. Addition of chloroform which turns blue as the complexed cocaine is 
partitioned into the organic phase. 
This method has several disadvantages. 
1. Complicated procedure; 
2. Non-portable kit; 
3. The ratio of solutions of steps (A), (B) is critical; 
4. It uses corrosive concentrated hydrochloric acid; and 
5. Trace amount of cocaine cannot be detected. 
Accordingly, there is still a need for a specific test kit for detection of 
cocaine and heroin street drug. 
Heroin street drug is not a pure chemical but a mixture of heroin, 
morphine, codeine, paparevine and nescapine salts, trace amounts of their 
corresponding free bases, traces of acetic acid and some diluents such as 
sugars, caffeine, phenoborbital and procaine. This is because clandestine 
laboratories manufacture illicit drugs with no quality control. 
In contradistinction thereto, medicinal drugs and pharmaceuticals 
containing an organic base are manufactured and sold as their pure salts. 
Manufacture is carried out in the pharmaceutical industry under strict 
quality control, so that these salts do not contain even trace amounts of 
free organic bases. 
Thus it has been found that 95% of heroin street drug contains trace 
amounts of free alkaloid bases. 
Dogs that are trained to reveal hidden heroin, are trained to detect trace 
amounts of acetic acid which is also one of the impurities in heroin 
street drug. 
Based on these findings it is now proposed that an efficient way to detect 
illicit drugs that were synthesized in a clandestine laboratory is to 
detect trace amounts of free organic base or acetic acid therein. 
Thus, contrary to the prior art approaches to the detection of heroin and 
cocaine, it has now been surprisingly found that a powder suspected of 
being cocaine base ["crack"] or being street drug heroin can be detected 
by its organic free base character. Furthermore, street drug heroin can 
also be identified by the characterizing presence of trace amounts of 
acetic acid. 
Thus in accordance with the present invention there is provided a process 
for the presumptive detection of cocaine and heroin street drug comprising 
applying to a sample of the suspected drug a reagent which gives a 
characteristic color reaction in the presence of trace amounts of organic 
bases or acetic acid. 
Preferably said process is carried out with a sulfonated aromatic pH 
indicator reagent which produces a color reaction in the presence of trace 
amounts of acetic acid as well as in the presence of trace amounts of 
organic free base. 
Preferably said sulfonated aromatic pH indicator is selected from the group 
consisting of bromophenol blue, bromochlorophenol blue and bromocresol 
green. 
As mentioned before, heroin street drug contains trace amounts of organic 
free base and acetic acid. Furthermore "crack" is cocaine free base and 
therefore sulfonated aromatic pH indicators which produce a color reaction 
in the presence of trace amounts of organic free base are also utilizable 
for the detection thereof. Such indicators as bromophenol blue, 
bromochlorophenol blue and bromocresol green give intense color when they 
react with trace amounts of free organic base and/or trace amounts of 
acetic acid. The preferred indicator is bromophenol blue, which gives an 
immediate intense violet color with traces of alkaloid bases such as 
heroin and gives an immediate blue color with cocaine. 
Because cocaine free base is the most frequent illicit drug as a free base, 
a positive blue reaction can be a presumptive detection test for cocaine. 
It can be further verified by the well known Scott modified cobalt 
thiocyante reagent. 
Thus in its preferred embodiment the present invention provides a test kit 
for the presumptive identification of cocaine and heroin street drugs 
comprising a reagent selected from sulfonated aromatic pH indicators which 
produces a color reaction in the presence of trace amounts of organic free 
base or acetic acid. 
Preferably and reagent is combined with the suspected drug in the presence 
of a halogenated organic solvent such as dichloromethane, trichloromethane 
and trichloroethane. 
Despite the high effectiveness of the above proposed identification test, 
it has been found statistically that the sulfonated aromatic pH indicators 
mentioned above do not react with about 5% of tested samples of heroin 
street drug (possibly because they were well prepared). 
While a test which is accurate in about 95% of the tested samples is 
already a major improvement in the art, nevertheless it is desirable to 
provide law enforcement and custom agents with means for also double 
checking the remaining 5% of samples which might in fact be heroin but 
which initially test out negative. 
In a modification of the simple one reagent test of the present invention 
there are provided two preferred multireagent tests which allow for 
positive elimination of a sample as being heroin or cocaine whereby if the 
results from both tests are negative it can be safely presumed that the 
sample does not contain cocaine or heroin. 
Thus according to one embodiment of the present invention there is provided 
a multi-reagent test kit for the presumptive identification or elimination 
of a sample as cocaine or street drug heroin comprising a sulfonated 
aromatic pH indicator which produces a color reaction in the presence of 
trace amounts of an organic base or acetic acid as a first reagent and a 
second reagent which converts salts of organic bases to their 
corresponding free bases. 
Thus in a case wherein the first test comes out negative it is proposed to 
apply a second reagent to the same sample or to a second one, said second 
reagent being selected from volatile organic bases such as ammonia and 
short chain aliphatic derivatives of ammonia, such as mono, di or tri 
methyl, ethyl, propyl and butyl amines, which turns alkaloids salts to 
their corresponding bases. 
By applying the first reagent once again, a violet color would be 
presumptive detection of alkaloids, however would be less specific for 
heroin than the preferred test of applying only the first reagent. If 
there is no violet color, the suspected powder can be presumed not to 
contain heroin. If there is a blue color, it is too general to be a 
presumptive test for an illicit drug; however if there is no blue or 
violet color at all it can be presumed that the suspected powder does not 
contain organic base at all. 
As an alternative there is also provided according to the present invention 
a multi-reagent test kit for the presumptive identification or elimination 
of a sample as cocaine or street drug heroin comprising a sulfonated 
aromatic pH indicator, which produces a color reaction in the presence of 
trace amounts of a base or acetic as a first reagent and a second reagent 
selected from picric acid, styphnic acid and derivatives thereof for 
forming a hydrophobic yellow colored cocaine or heroin salt. 
As is known organic bases or their salts tend to form a highly hydrophobic 
salt with aromatic compounds having at least one hydroxyl group that 
functions as the acidic part and electron attracting groups that strongly 
influence the acidic character of the hydroxy groups such as nitro, cyano, 
and sulphonic substituents. 
However heretofor it has not been suggested to form a colored salt from the 
reaction of picric or styphnic acid and heroin or cocaine. 
Thus picric acid which is a 2,4,6-trinitrophenol and styphnic acid which is 
a 2,4-dihydroxy-1,3,5 trinitrobenzene are suitable and preferred for use 
in the present invention. 
Furthermore styphnic and picric acid form electron-donor-acceptor 
charge-transfer (CT) complexes. Some of them are colored complexes. 
Organic aromatic molecules that have one or two hydroxy groups and several 
electron attracting substituents that can cause the hydroxy group to 
function as an acid can be used as an electron acceptor in CT complexes. 
Polycyclic aromatic molecules without or with electron releasing 
substituents such as alkyl and alkoxy can form a CT colored complex with 
the previously defined aromatic acids. CT reactions are usually 
accomplished in molar ratio. 
Picric acid and styphnic acid are phenolic organic acids, and they form CT 
colored complexes with the following polycyclic aromatic compounds: 
Anthracene--Ruby red 
Chrysene--Orange red 
Pyrene--Dark Red 
Benz(a)anthracene--Dark red 
Azulene--Brown Violet 
CT complexes formed with anthracene and its ether derivatives such as 
dimethyl and diethyl ethers of the following dihydroxy anthracenes: 1,2; 
1,5; 1,8; 1,9; 2,3; 2,6; 2,7; 9,10 are preferred and a CT complex of 
picric acid and anthracene is especially preferred. 
When, for example, the picrate CT complex reacts with heroin in anhydrous 
conditions yellow ammonium picrate salt is immediately formed. 
Thus the above acids which are similar in properties, reactions and the 
characterizing yellow salts which they form with heroin can be used in 
many ways as described hereinafter with regard to picric acid, it being 
understood that reagents using styphnic acid are similarly prepared. 
The invention can therefore be carried out with regard to the use of the 
second reagent in the following various ways: 
1. Dissolving heroin in a slightly acidic (hydrochloric acid, phosphoric 
acid) aqueous solution and adding a few drops of aqueous solution of 
picric acid, a heavy yellow precipitate is formed, which is the 
hydrophobic heroin picrate salt. 
2. Picric acid is slightly colored in organic solvent, such as benzene, 
chloroform, and dichloromethane. By adding a few drops of such a solution 
of a suspect substance on a filter paper, an intense yellow lemon salt is 
formed with slightly colored background. 
3. A suspect substance is put on a paper impregnated with picric acid and a 
few drops of anthracene solution (from a dropper, prepackaged canister or 
dispenser) are added which stain the paper with red color except the area 
where there is heroic which turns an intense yellow color. 
4. Using paper impregnated with anthracene and anhydrous organic solution 
of picric acid, a few drops of the solution placed on a sample of the 
suspect material placed on the reagent impregnated paper to give the 
desired color reaction. 
5. Using paper impregnated with picric acid-anthracene ct complex, a few 
drops of solvent are placed on a sample of the suspected material placed 
on the reagent impregnated paper to give an intense yellow color with red 
background. 
In an especially preferred embodiment of the present invention said first 
reagent is incorporated in a multilayer analytical element comprising an 
intermediate layer of absorbent substrate impregnated with said reagent, a 
bottom water-impermeable support layer and an upper hydrophobic protecting 
layer permeable to heroin dissolved in an organic solvent and impermeable 
to organic insoluble compounds. 
The support layer is preferably polyethylene (Benchkote) [manufactured by 
Whatman of England]. It has the following characteristics: 
1. It prevents humidity from penetrating into the back side of the 
analytical layer due to the polyethylene support and backing layer 
provided therein; and 
2. It prevents cross contamination by the use of the kit. 
The hydrophobic blocking layer is a hydrophobic special glue with the 
following characteristics: 
1. Keeps any humidity from the analytical layer; 
2. Sticks the suspected substance to the analytical element; and 
3. Prevents passage of organic insoluble compounds while being pemeable to 
heroin using an organic solvent such as methylene chloride and chloroform, 
thus reducing the chances of obtaining a false positive to a minimum. 
The preferred glues area: 
1. 4550 - SB-R (3M Co. U.S.A.); 
2. 4910-NF-dissolved in 1,1,1-TCE (3M Co. U.S.A.). 
This preferred multilayer analytical element consists of a sheet of 
cellulose porous matrix in which the analytical layer is between the 
support and the blocking layer. The suspected substance is placed on the 
surface of the solid phase blocking layer. By applying dichloromethane on 
the surface it diffuses into the matrix of the analytical layer and in so 
doing dissolves the component reagents dispersed therein. When the dry 
reagent has dissolved, it reacts with the suspected compound to generate a 
colored product on the surface of the multilayer analytical element. 
The performance of the reagents when impregnated in a porous cellulosic 
matrix are improved by silanizing the filter papers. Silanizing reagents 
block the hydroxy groups of the cellulose. The filter paper becomes highly 
hydrophobic (water repellent). The improvements are: 
1. Reagents placed on the filter paper are not sensitive to moisture at 
all; 
2. The contrast of the colored reaction and the sensitivity of the reagents 
based on picric acid when placed on filter paper are improved. 
3. The above-mentioned hydrophobic glues can also be applied as a blocking 
layer to silanized filter paper impregnated with a first reagent based on 
picric acid. 
The preferred silanizing reagents are; 
1. Dimethyldichlorosilane; 
2. Trimethylchlorosilane; and 
3. Dimethylchlorosilane. 
The reagents are simply poured on the surface of the paper and air dried. 
Both said first and said second reagents can alternatively be packaged in 
separate aerosol containers and dispensers in combination with a 
propellant selected from compressed air, a fluorohydrocarbon, a 
chloro-fluorohydrocarbon, CO.sub.2 gas, nitrous oxide or N.sub.2 gas 
although simple pump (without propellant) dispensers can also be used. 
The concentration of the reagent in organic solvent can range from about 
0.1% by weight/volume up to 3% and it is preferred that sufficient reagent 
be present in the solution so that one spray application will dispense 
sufficient reagent to bring out the characteristic color reaction with the 
heroin street drug. 
However, as indicated hereinbefore, in an especially preferred embodiment 
of the present invention both said first and said second reagents are 
incorporated in a multilayer analytical element comprising an intermediate 
layer of absorbent substrate impregnated with said reagent, a bottom 
water-impermeable support layer and an upper hydrophobic protecting layer 
permeable to heroin or cocaine dissolved in an organic solvent and 
impermeable to organic insoluble compounds, in which the absorbent 
substrates are preferably silanized cellulosic matrices. 
As discussed hereinbefor if there is no color reaction with said first 
reagent the invention provides for applying to the same sample or to a 
second sample, a second reagent comprising a volatile base for forming the 
corresponding free bases from heroin street drug and then applying once 
again the first reagent, or applying to a second sample a second 
alternative reagent selected from picric acid, styphnic acid and 
derivatives thereof for forming a hydrophobic yellow colored heroin salt. 
The above possible sequential tests and presumptive results thereof are 
illustrated in the following flow chart.

While the invention will now be described in connection with certain 
preferred embodiments in the following examples so that aspects thereof 
may be more fully understood and appreciated, it is not intended to limit 
the invention to these particular embodiments. On the contrary, it is 
intended to cover all alternatives, modifications and equivalents as may 
be included within the scope of the invention as defined by the appended 
claims. Thus, the following examples which include preferred embodiments 
will serve to illustrate the practice of this invention, it being 
understood that the particulars shown are by way of example and for 
purposes of illustrative discussion of preferred embodiments of the 
present invention only and are presented in the cause of providing what is 
believed to be the most useful and readily understood description of 
formulation procedures as well as of the principles and conceptual aspects 
of the invention. 
EXAMPLE 1 
A few miligrams of material suspected as heroin street drug are placed on 
filter paper. A few drops of 5% Bromophenol blue in chloroform are added. 
A violet color is formed with yellow background thus establishing a strong 
presumption that the tested sample is indeed heroin. 
EXAMPLE 2 
First impregnation stage: 
Filter paper (Benchkote) was impregnated by dipping into a solution 
containing 1% bromophenol blue in dichloromethane. Following impregnation, 
the paper was dried at 60.degree. C. for few minutes. 
Second impregnation stage; 
The dry impregnated paper from the first stage was then impregnated by 
spreading a viscous solution of 30% glue (4550-B-R-fsu) in dichloromethane 
on the impregnated paper. 
Test: A few miligrams of a suspected heroin street drug are placed on the 
glue surface. Adding 2-3 drops of dichloromethane results in the staining 
of the paper in violet color with yellow background, thus presumptively 
identifying the sample as heroin. 
EXAMPLE 3 
The procedure of example 2 was repeated preparing a multilayer analytical 
element with bromochlorophenol blue as reagent and 4910-NF(3.mu.) as the 
glue. Wetting of the suspected material with dichloromethane results in 
the staining of the paper with a violet color with yellow background. 
EXAMPLE 4 
The procedure of example 2 was repeated preparing a multilayer analytical 
element with bromocresol green as reagent and 4910-NF(3.mu.) glue. Wetting 
of the suspected material with dichloromethane results in the staining of 
the paper with a green color with yellow background. 
EXAMPLE 5 
The procedure of example 2 was repeated. However the filter paper was first 
silanized with dimethylchlorosilan. The thus treated analytical element 
also produced a violet color with yellow background, but with less 
sensitivity to humidity. 
EXAMPLE 6 
The impregnation steps of example 2 are repeated. A few miligrams of 
suspected cocaine base ("crack") are placed on the glue surface. Adding 
2-3 drops of dichloromethane results in the staining of the paper in blue 
color with yellow background. 
EXAMPLE 7 
The procedure of example 3 was repeated. Wetting of the suspected cocaine 
base with dichloromethane results in the staining of the paper with a blue 
color with yellow background. 
To later vertify cocaine, the Scott test, in which cobalt thiocyanate 
reagent in 1:1 water: glycerine solution forms characteristic blue 
precipitate with cocaine, L.J. Scott, Specific Field Test for Cocaine, 
Microgram VI, 179 (1983),is used. 
EXAMPLE 8 
If there is no color reaction in samples tested according to examples 1-5 
then there is applied a few drops of 0.01% methylamine in chloroform on 
the same sample. Once again applying a few drops of 0.5% Bromophenol blue 
in dichloromethane results in the formation of a violet color with faint 
blue background which is indicative for heroin samples while no violet 
color reaction is indicative of non-heroin samples. 
EXAMPLE 9 
The procedure of examples 1-5 are repeated. If there is no reaction, there 
is applied on the same sample of suspected heroin street drug a few drops 
of diethylamine in dichloromethane which results in the formation of a 
violet color with blue background when the sample is in fact heroin and no 
violet color when the sample is not heroin. 
EXAMPLE 10 
The procedure of example 6 was repeated. If there is no reaction there is 
applied a few drops 0.01% of ammonia in chloroform on the same suspected 
cocaine sample. If there forms a blue color that does not disappear, it is 
indication of a salt of an organic base, and the possibility that the 
sample is cocaine cannot be dismissed and must be further verified in the 
lab. 
EXAMPLE 11 
The procedure of example 1 was repeated. If there is no color, a few 
miligrams of suspected heroin street drug are placed on a filter paper. A 
few drops of 3% picric acid in chloroform are added. If a yellow color is 
formed with slightly colored background, it is an indication that the 
sample is a salt of an organic base and therefor might be pure heroin 
requiring further laboratory testing. On the other hand a negative result 
also with this reagent is confirmation that the tested sample is not 
heroin 
EXAMPLE 12 
The procedure of example 1 was repeated. If there is no reaction a few 
drops of 0.5% picric acid-anthracene red complex in dichloromethane 
(wherein picric acid and the anthracene derivative are present in 1:1 
molar ratio) are added. If a yellow color with red background is formed, 
it is indication for a salt of an organic base with the same presumptions 
and conclusions as in the previous example. 
It will be evident to those skilled in the art that the invention is not 
limited to the details of the foregoing illustrative examples and that the 
present invention may be embodied in other specific forms without 
departing from the essential attributes thereof, and it is therefore 
desired that the present embodiments and examples be considered in all 
respects as illustrative and not restrictive, reference being made to the 
appended claims, rather than to the foregoing description, and all changes 
which come within the meaning and range of equivalency of the claims are 
therefore intended to be embraced therein.