Narcotics Drugs in Forensics: Analytical Review of Narcotics in Forensics.

1. Introduction

Narcotic substances, opioids and opioid-like substances in particular are one of the greatest forensic and population health issues facing the global community. Conventionally, the word narcotic was used to mean those substances that brought sleep and pain-relieving effects, which were mainly opium derived. But in the current forensic and legal terms, narcotics are widely referred to as being natural, semi-synthetic and synthetic opioids and even some other substances under the control of the central nervous system that can cause depression.

The world drug situation has changed significantly over the past few decades. Although heroin used to reign the illegal opioid markets, the synthetic opioids like fentanyl and its derivatives have become significantly more dangerous since they are highly potent. According to the United Nations Office on Drugs and Crime (UNODC), an impressive percentage of the number of opioid overdose deaths worldwide is caused by synthetic opioids (UNODC World Drug Report, 2023).

Narcotic investigations have a number of dimensions in terms of forensic factors:

• Determination of seized drug material.
• Purity and composition determination.
• In fatality as a result of overdoses, toxicological examination is conducted.
• Drug profiling and source attribution.
• Blood and tissue drug interpretation.
• Scientific findings as presented in a courtroom.
• Forensic narcotic analysis is, therefore, an interpretative and analytical type of analysis.
• Scheduling of Narcotic Drugs.

2. Learning how to classify narcotics is the core of forensic drug examination.

2.1 Natural Opiates

Natural opiates are directly obtained from the opium poppy (Papaver somniferum). The main natural alkaloids are:

Morphine, Codeine and Thebaine

Morphine is available in the market as a painkiller medicine, but it is abused as well because of its euphoric nature. Morphine detection is commonly used in clinical toxicology and in criminal investigations in forensic laboratories.

2.2 Semi-Synthetic Opioids

Semi-synthetic opioids are the modified derivatives of the natural opiates that are chemically modified. These include:

Heroin (diacetylmorphine), Oxycodone and Hydromorphone.

The rapid conversion of heroin to 6-monoacetylmorphine (6-MAM) and morphine occurs in the body. In forensic toxicology, the 6-MAM is regarded as conclusive proof of heroin use. Analytical studies stress the significance of metabolite identification instead of the parent drug only (Maurer, 2010).

2.3 Synthetic Opioids

Synthetic opioids are totally man-made materials. Examples include: Fentanyl, Carfentanil, Methadone and Tramadol.

Fentanyl is between 50-100 times more potent than morphine, and carfentanil is thousands of times more potent. These compounds are very lethal in low concentrations, and as such, they need very sensitive analytical methods to be detected.

The development of fentanyl analogues poses serious forensic implications, due to the fact that simple chemical alterations will result in the formation of new substances, which cannot be detected right away, with the help of traditional screening libraries.

3. Pharmacological Mechanism and Toxicological Implication.

The actions of narcotic drugs are achieved through the connection of the drugs to the opioid receptors (mostly the μ-receptors) in the brain and the spinal cord. This contact decreases the perception of pain and gives rise to euphoria. Nevertheless, too much receptor activation inhibits respiratory centres, causing hypoxia and eventual death in overdose patients.

Determination of the cause of death in cases of narcotic overdose in forensic toxicology entails:

• Determining blood drug levels.
• Assessing co-intoxicants (alcohol, benzodiazepines, etc
• Evaluation of history and tolerance.
• Taking into account postmortem redistribution.

Postmortem redistribution is the redistribution of drugs following death as a result of diffusion of tissue back to blood. This makes it difficult to interpret because the levels in central blood might not indicate the levels at antemortem (Drummer, 2004).

This is why toxicological interpretation should not be judged with scientific care and context-dependent analysis; instead, it relies on rigid numeric values.

4. Analytical Methods of Narcotic Detection in Forensics.  

The forensic science of drug studies relies on the analytical detection and identification of narcotic drugs.  As the drug market is becoming more challenging, with a wave of synthetic analogues going on the market, and because the results must withstand a trial, a multifaceted approach is implemented in the forensic labs.  We make rapid presumptive screening, then verify by means of expensive equipment, and then extract the numbers of all the toxic substances that are present.  All these actions are necessary to maintain the evidence hard, credible, and admissible.  

4.1 Presumptive (Screening) Techniques.  

The initial step we make whenever we run an examination on drug evidence is presumptive tests.  They are to provide us with a rapid hint of what can be found in a sample, in particular, as we go out in the field or as we get a fresh batch into the lab.  

Spotting opioids by colourimetric tests, an example is the classic Marquis, Mecke, and Mandelin reagents.  An example is that the heroin becomes purple in the presence of Marquis reagent due to a chemical reaction of morphine derivatives.  They are cheap and quick but not very specific; any similar compounds will be the same colour, causing the appearance of a false alarm.  

Immunoassays are also standard in modern-day labs.  ELISA and FPIA screening identify drugs through the binding of antibodies containing target molecules.  Their application is very popular in toxicology laboratories for urine and blood samples.  Although they are helpful, cross-reactivity implies that some subject-related compounds may trigger a positive, and hence, we will always require confirmatory work.  

Conclusion—you never rely on presumptive results; these are only the initial hints, which make us enter into more profound examination.  

4.2 The gas chromatography-mass spectrometry (GC-MS):

 The technique is used to detect the concentration of acetone, benzene, and other compounds in the product. To determine the concentration of acetone, benzene, and acetone in the product, the gas chromatography-mass spectrometry (GC-MS) method is utilised.  

The gold standard in the identification of drugs is still GC-MS.  It combines two powerful methods: gas chromatography, which separates compounds based on the volatility of the compound (and their interaction with the column), and mass spectrometry, which identifies the compounds based on the fragment pattern.  

Under GC-MS, each drug in the analysis will have a distinctive mass spectrum, which we compare to known libraries to verify.  We can scrutinise heroin, morphine, codeine, and a large number of other semi-synthetic opioids off the shelf.  

Not everything will go smoothly – some of the synthetic opioids or heat-sensitive substances may decompose when vaporised.  In such situations, we do derivatisation in order to stabilise the molecules.  Nonetheless, GC-MS does not lose its place in the courtroom, as it has long-term validation and provides reproducibility of the findings.  

We are also able to operate quantitative GC-MS versions to determine the purity of drugs that have been seized, which aids in the realisation of trafficking volumes and supply chains.  

4.3 Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) 

The LC-MS/MS has emerged as the new standard in the field of toxicology, particularly with respect to the recent synthetic opioids such as fentanyl analogues.  It does not require the vaporisation of the sample like GC-MS, and as such, we are fine with heat-sensitive or highly polar drugs.  In LC-MS/MS, liquid chromatography separates the compounds according to their polarity.  The tandem mass spectrometer then undergoes repeated rounds of mass filtering, which dramatically increases sensitivity and selectivity, which is crucial when we are targeting ultra-potent opioids which appear in nanograms or even picograms per sample.  

In this method, we can also simultaneously identify numerous narcotics and their metabolites.  It is massive in terms of overdose cases, as we are able to screen not only opioids but also benzodiazepines, antidepressants, and other co-intoxication in a single run.  

Due to the fact that LC-MS/MS is sensitive and reliable, it is slowly replacing GC-MS in routine toxicological quantification.  

4.4 Non-Targeted Screening and High-Resolution Mass Spectrometry (HRMS).  

The influx of new psychoactive drugs, and particularly synthetic opioids, has compelled us to embrace HRMS.  It gives the precise mass values with mind-boggling accuracy, and thus we can recognise unknown compounds even when we do not have a standard available.  

In contrast to specific tests that are aimed at identifying pre-determined substances, HRMS is a non-specific screening.  That allows the labs to return to archived information and detect the emerging narcotics that were not on the initial panels.  HRMS particularly comes in handy to deal with fentanyl analogues, designer opioids or structurally modified weapons that can be used to get around legal limitations.  HRMS focuses our general forensic arsenal by unlocking molecular formulas and fragment patterns because the drug markets continue to evolve rapidly.  

4.5 Spectroscopic Methods in laboratory and field applications.  

Handheld spectroscopic devices are transforming the process of identifying drugs on the street.  Raman and FTIR spectrometers that fit into the palm of the hand allow us to determine substances without making an intrusion into them. Raman is bright as it is able to read through clear packaging, reducing the chance of contamination.  In the meantime, FTIR can provide rapid spectral comparison with drug libraries, useful at the border or a crime scene, to provide an initial attempt. Of course, they are not as sensitive as mass spectrometry; however, they are really quick, portable, and quite convenient in the field.  

4.6 New Nanotechnology-Based and Microfluidic Technologies.  

More recent technology is adding nanomaterials, such as gold nanoparticles. These colourimetric tests change colour when they are affected by certain opioids through surface plasmon resonance.  They are cheap, fast and have the potential for quick checkups.  

There is also an uproar of microfluidic lab-on-a-chip devices.  These micro-sized platforms are one-third sample preparation, separation and detection.  Assuming that they continue to validate themselves, they might transform real-time screening using low volumes of samples.  Although these advances are yet to be tested, they indicate the way forensic analytical science continues to develop.

5. Drug Profiling and Source Attribution.

Drug profiling is a sophisticated forensic method that is applied to establish the source, production, and outlets of illegal narcotics. In contrast to the routine drug identification, which identifies a substance as a chemical, profiling is used to identify chemical signatures, i.e. impurities, by-products, and trace elements, which are produced by certain synthesis methods or by certain precursor materials.

Profiling of impurities is the analysis of chemicals that are left behind in the production of illicit drugs. These contaminants are chemical fingerprints, and on comparison of various seizures, the forensic laboratories can determine the possible connections between batches. Gas chromatography and high-performance liquid chromatography are usually used in order to separate and characterise these trace compounds.

The source attribution is further improved by the use of the isotope ratio mass spectrometry (IRMS) that measures the ratios of the stable isotopes (e.g., carbon and nitrogen), which can be characteristic of geographical and environmental variation in raw materials. It is especially applied when working with heroin and cocaine cases, when the investigator has to deal with plants. Besides, inorganic profiling with methods like inductively coupled plasma mass spectrometry (ICP-MS) can identify trace metals used as catalysts and reagents or as manufacturing equipment. Jointly with statistical techniques like principal component analysis (PCA), the forensic scientists can make objective comparisons on chemical datasets and determine a relationship among drug samples.

Even though drug profiling is very useful in terms of intelligence accessible to formulate seizure linkages and trace trafficking routes, the findings are likely rather than definite. Thus, profiling evidence is normally employed to aid in investigational intelligence and should be cautiously applied in the law.

6. Conclusion

The narcotic drugs pose the most complicated problems in the field of forensic science because of the development of new synthetics, low fatal doses, and interpretative challenges in the cases of overdose. Although the methods such as GC-MS are still fundamental, the new techniques such as LC-MS/MS and HRMS show improved sensitivity that is required in identifying the presence of potent synthetic opioids. The profiling of drugs and sophisticated interpretation of toxicology enhance investigations and criminal justice. Further studies, technological development, and thorough validation will make sure that forensic narcotic analysis will be scientifically sound and legally sound.