Screening/spot test of narcotics

Narcotics are the substances used to treat moderate to severe pain. They could be natural like opiates such as morphine, codeine etc., synthetic like fentanyl, methadone etc., and semi-synthetic like oxycodone, hydrocodone etc. These drugs act as pain relievers, induces the state of stupor or sleep, and increase the physical dependence on them. In forensic autopsy case, the forensic pathologist may require a complete toxicological investigation for different poisons including stimulants. In India, Forensic Science Laboratories run by Government under the Home ministry usually carry out this. The samples must be analysed by the forensic toxicologist/chemists/scientist. This article deals with the screening/spot test for narcotics. It attempts to simplify the standard procedures in a step-wise manner, which can be of handy reference for the forensic toxicologist. © This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Introduction
Narcotics, the word is borrowed from the Greek word 'narkōtikós', which means lethargic or stuporous. The expression narcotic is generally used to refer to a class of drugs that are analgesics, central nervous system depressants and produces insensibility or stupor. Narcotics commonly termed as Opioids, usually produces analgesia, mood swings, physiological dependence, heavy tolerance and a hedonic or rewarding effect, which contributes to compulsive use of the drug by the abuser. The effects caused by narcotics include euphoria, drowsiness, respiratory, depression, constipation, constricted pupils. Narcotics majorly attacks the Central Nervous System and Peripheral Nervous System and usually found in these areas as well as in the Gastrointestinal Tract. Such drugs act by binding to opioid receptors in the body, as narcotics mediate both the psychoactive and somatic effects of opioids, though they do not cross the blood-brain barrier, but can shift other opioids from binding to the respective receptors. Forensic Scientists/Toxicologists have a hard time in searching appropriate tests to analyse samples of narcotics in medicolegal cases, autopsies, and even for academic purposes. [1][2][3][4][5][6][7][8][9] In India, The Narcotic Drugs and Psychotropic Substance (NDPS) Act, 1985 covers all kinds of activities related to narcotic substances. Bare act reads as follows: "An Act to consolidate and amend the law relating to narcotic drugs, to make stringent provisions for the control and regulation of operations relating to narcotic drugs and psychotropic substances [to provide for the forfeiture of property derived from, or used in, illicit traffic in narcotic drugs and psychotropic substances, to implement the provisions of the International Conventions on Narcotic Drugs and Psychotropic Substances] and for matters connected therewith." 10 In simplified terms, the act states that possessing, manufacturing, production, selling, transportation, purchasing, inter-state importing and exporting, or using cannabis is punishable with rigorous imprisonment attracting ten years of jail or fine extending up to one lakh rupees.
We have tried to set out standard procedures for screening/spot test for narcotics that are easily available and useful for the forensic science laboratory.

Marquis test
29. Preparation of Solutions 1. Ferric chloride solution: 10 g of ferric chloride is dissolved in 100 ml distilled water. 2. Folin-Ciocalteau reagent: Dissolve 100 g of sodium tungstate and 25 g of sodium molybdate in 800 ml of purified water in a 1.5-l flask. Add 50 ml of concentrated orthophosphoric acid and 100 ml of concentrated hydrochloric acid and reflux for 10 hours. Cool, add 150 g of lithium sulfate, 50 ml of purified water and 0.5 ml of elemental bromine, and allow to stand for 2 hours. Boil for 15 minutes to remove excess bromine, cool, filter if necessary, and dilute to 1 litre with purified water. This solution is yellow and should be stable for 4 months if stored at 4 • C. 3. Froehde's reagent: 1 g of molybdic acid or sodium molybdate is dissolved in 100 ml of hot concentrated sulphuric acid. 4. Lie bermann's reagent: 1 gm of sodium or potassium nitrite is dissolved in 10 ml of sulphuric acid with cooling and swirling to absorb the brown fumes. 5. Mandelin's reagent: 1 g of ammonium vanadate is dissolved in 1.5 ml of water and dilute to 100 ml with concentrated sulphuric acid. 6. Marquis reagent: 100 ml of concentrated sulphuric acid is mixed with 1 ml of formaldehyde solution.

Source of Funding
None.

Conflict of Interest
None.