21 Questions
Match the color changes with the corresponding reagent: Marquis' reagent for opium alkaloids
White > green > turquoise = Initial color change Brownish black = Resulting color
Match the color changes with the corresponding reagent: Ehrlich's reagent for hallucinogens
Orange-red = Initial color change Pink-purple = Resulting color
Match the color changes with the corresponding reagent: Duquenois-Levine's reagent for cannabinoids
Violet = Initial color change Pink = Resulting color
Match the color changes with the corresponding reagent: Mandelin's reagent for methadone
Blue = Initial color change Green = Resulting color
Match the color changes with the corresponding reagent: Dragendorff reagent for alkaloids
Orange-brown = Initial color change Reddish brown = Resulting color
Match the reagent with the correct initial and resulting colors for detecting opium alkaloids:
Marquis' Reagent = Orange Ehrlich's Reagent = Yellow Duquenois-Levine's Reagent = Light yellow Mandelin's Reagent = No reaction
Associate the reagent with the corresponding initial and resulting colors for identifying hallucinogens:
Marquis' Reagent = Purple Ehrlich's Reagent = Violet Duquenois-Levine's Reagent = Yellow Mandelin's Reagent = Pale yellow
Match the reagent with the correct initial and resulting colors for detecting cannabinoids:
Marquis' Reagent = Brown Ehrlich's Reagent = Red Duquenois-Levine's Reagent = Light yellow Mandelin's Reagent = No reaction
Associate the reagent with the corresponding initial and resulting colors for identifying methadone:
Marquis' Reagent = Orange-brown Ehrlich's Reagent = Violet Duquenois-Levine's Reagent = Yellow-green Mandelin's Reagent = No reaction
Match the reagent with the correct initial and resulting colors for detecting alkaloids like cocaine and heroin:
Marquis' Reagent = Purple Ehrlich's Reagent = Violet Duquenois-Levine's Reagent = Yellow Dragendorff Reagent = Yellow-green
Match the reagent with the substances it can detect:
Ehrlich's reagent = Indoles and tryptamines Marquis' reagent = Opiates and opioids Duquenois-Levine's reagent = Cannabinoids Mandelin's reagent = Phenethylamines
Match the reagent with its primary usage in drug detection:
Ehrlich's reagent = Identifying hallucinogens Marquis' reagent = Detecting opium alkaloids Duquenois-Levine's reagent = Testing for cannabinoids Mandelin's reagent = Detecting phenethylamines
Match the color produced under ultraviolet light with the corresponding reagent-substance combination:
Yellow-green fluorescence - MDMA (ecstasy) = Mandelin's reagent Purple color - Tryptamines = Ehrlich's reagent Brown color - Opiates = Marquis' reagent Blue color - Cannabinoids = Duquenois-Levine's reagent
Match the metals that Dragendorff's reagent can detect:
Gold, aluminum, copper = Dragendorff's reagent Silver, iron, nickel = Marquis' reagent Lead, zinc, tin = Duquenois-Levine's reagent Platinum, mercury, palladium = Mandelin's reagent
Match the limitation in drug detection with the corresponding reagent:
Cannot reliably distinguish different types of opioids without additional testing = Dragendorff's reagent Limited use in detecting specific types of alkaloids like cocaine and heroin = Duquenois-Levine's reagent Does not provide conclusive identification of all hallucinogens = Ehrlich's reagent Limited effectiveness in differentiating between various phenethylamines = Mandelin's reagent
Match the reagent with the substances it is used to detect:
Ehrlich's Reagent = Amines like heroin, cocaine, morphine Marquis' Reagent = Phenolic compounds like THC, MDMA Duquenois-Levine's Reagent = Cannabinoids like THC, CBD Mandelin's Reagent = Hallucinogens
Match the reagent with the color change it produces upon reaction:
Ehrlich's Reagent = Purple or red Marquis' Reagent = Greenish-blue fluorescence under long-wave ultraviolet light Duquenois-Levine's Reagent = Reddish-purple Mandelin's Reagent = Color change not specified
Match the reagent with its components:
Ehrlich's Reagent = Methylene blue Marquis' Reagent = Chloroantimony trioxide and monobromoglucose Duquenois-Levine's Reagent = Concentrated sulfuric acid and vanillin Mandelin's Reagent = Components not specified
Match the reagent with its primary usage:
Ehrlich's Reagent = Detecting amines Marquis' Reagent = Detecting phenolic compounds Duquenois-Levine's Reagent = Detecting cannabinoids Mandelin's Reagent = Usage not specified
Match the reagent with its application field:
Ehrlich's Reagent = Detecting amines in substances like heroin, cocaine, morphine Marquis' Reagent = Detecting phenolic compounds in pharmaceuticals and illegal drugs like THC, MDMA Duquenois-Levine's Reagent = Detecting cannabinoids like THC, CBD Mandelin's Reagent = Application field not specified
Match the reagent with its color spot test application:
Ehrlich's Reagent = Turns purple or red when detecting amines Marquis' Reagent = Produces greenish-blue fluorescence under long-wave ultraviolet light when detecting phenolic compounds Duquenois-Levine's Reagent = Results in a reddish-purple color change when detecting cannabinoids Mandelin's Reagent = Color spot test application not specified
Study Notes
Color Spot Tests
Color spot tests have become increasingly popular in forensic science laboratories due to their simplicity and speed in identifying various illicit drugs. These tests involve the application of a chemical reagent onto an impure sample or solid substance, which allows for the detection of specific compounds based on their color change. In this article, we will focus on five color spot tests: the Marquis' reagent for opium alkaloids, Ehrlich's reagent for hallucinogens, Duquenois-Levine's reagent for cannabinoids, Mandelin's reagent for methadone, and Dragendorff reagent for alkaloids.
Marquis' reagent for Opium Alkaloids
The Marquis reagent is a spot test for alkaloids that was first developed in 1896. It consists of a mixture of potassium iodobismuthate (III) and potassium nitrate, which turns blue when it reacts with opioids like morphine or codeine. The initial color change is white > green > turquoise, indicating opiate presence. The resulting color is typically brownish black after heating.
Ehrlich's Reagent for Hallucinogens
Ehrlich's reagent is used to detect primary amines found in hallucinogenic compounds such as LSD. When applied to an LSD sample, it produces an orange-red color. After exposure to iodine vapor, the same sample will produce a pink-purple color due to the formation of the p-dimethylamino-benzaldehyde complex. Both these colors indicate the presence of LSD.
Duquenois-Levine's Reagent for Cannabinoids
The Duquenois-Levine reagent was developed to detect cannabinoids, primarily THC. It consists of vanillin, acetaldehyde, concentrated hydrochloric acid, and chloroform. Upon application to a marijuana sample, it exhibits a light yellow color. After adding concentrated hydrochloric acid, the mixture may turn blue-violet if cannabinoids are present. Additionally, chloroform should extract the color from the mixture, showing a purple color in the organic layer, further confirming the presence of cannabinoids.
Mandelin's Reagent for Methadone
Mandelin's reagent is used to identify methadone, a synthetic opioid. When applied to a methadone sample, it initially shows no reaction. However, upon addition of concentrated hydrochloric acid, a reddish-brown color appears. If the sample contains methadone, the color will deepen to dark red-brown, but if not, it will remain pale yellow.
Dragendorff Reagent for Alkaloids
Dragendorff's reagent is another spot test used to detect alkaloids, including cocaine and heroin. When applied to a sample containing these drugs, it first shows a yellow-green color. Then, after heating the mixture, it develops a bright yellow-orange color. For pure samples, the initial yellow-green color becomes deeper, ranging from gold to orange-red, while for impure samples, it remains yellow-green.
In conclusion, color spot tests have played a critical role in detecting various illicit drugs. By understanding the specific color changes associated with each reagent, forensic scientists can quickly identify and classify different drug types, helping to combat drug-related crimes and protect public health.
Learn about the popular and effective color spot tests used in forensic science laboratories to identify illicit drugs such as opium alkaloids, hallucinogens, cannabinoids, and alkaloids. Explore the specific reagents used, color changes observed, and their significance in drug detection and classification.
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