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Questions and Answers
Match the color changes with the corresponding reagent: Marquis' reagent for opium alkaloids
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
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
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
Match the color changes with the corresponding reagent: Mandelin's reagent for methadone
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Match the color changes with the corresponding reagent: Dragendorff reagent for alkaloids
Match the color changes with the corresponding reagent: Dragendorff reagent for alkaloids
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Match the reagent with the correct initial and resulting colors for detecting opium alkaloids:
Match the reagent with the correct initial and resulting colors for detecting opium alkaloids:
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Associate the reagent with the corresponding initial and resulting colors for identifying hallucinogens:
Associate the reagent with the corresponding initial and resulting colors for identifying hallucinogens:
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Match the reagent with the correct initial and resulting colors for detecting cannabinoids:
Match the reagent with the correct initial and resulting colors for detecting cannabinoids:
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Associate the reagent with the corresponding initial and resulting colors for identifying methadone:
Associate the reagent with the corresponding initial and resulting colors for identifying methadone:
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Match the reagent with the correct initial and resulting colors for detecting alkaloids like cocaine and heroin:
Match the reagent with the correct initial and resulting colors for detecting alkaloids like cocaine and heroin:
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Match the reagent with the substances it can detect:
Match the reagent with the substances it can detect:
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Match the reagent with its primary usage in drug detection:
Match the reagent with its primary usage in drug detection:
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Match the color produced under ultraviolet light with the corresponding reagent-substance combination:
Match the color produced under ultraviolet light with the corresponding reagent-substance combination:
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Match the metals that Dragendorff's reagent can detect:
Match the metals that Dragendorff's reagent can detect:
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Match the limitation in drug detection with the corresponding reagent:
Match the limitation in drug detection with the corresponding reagent:
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Match the reagent with the substances it is used to detect:
Match the reagent with the substances it is used to detect:
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Match the reagent with the color change it produces upon reaction:
Match the reagent with the color change it produces upon reaction:
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Match the reagent with its components:
Match the reagent with its components:
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Match the reagent with its primary usage:
Match the reagent with its primary usage:
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Match the reagent with its application field:
Match the reagent with its application field:
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Match the reagent with its color spot test application:
Match the reagent with its color spot test application:
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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.
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Description
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.
