The peculiarity of using the scientific method in forensic science is the impossibility of applying it to past events. It is impossible to use experiment, observation, deduction, and prediction, among the characteristics of the traditional scientific method (Saferstein & Roy, 2020). In other words, forensic science uses a slightly modified method to obtain an objective perception of past events. It includes the observation of the findings found on the crime scene, the results of the autopsy, and the comparison of the anamnestic data (Saferstein & Roy, 2020). The forensic scientist should learn whether the suspect or the witness lies or tells the truth using the scientific method, which is essential in articulating the conclusions.
The scientific method is critical when the forensic scientist has to conduct a qualitative and quantitative analysis of a suspected illegal drug sample. The concluding expert opinion that the sample contains heroin with a purity of 60% is obtained after the protocol is filled. Forensic scientist needs to separate all compounds in the samples they receive to measure the amount of the drug (Saferstein & Roy, 2020). Two types of tests allow forensic scientists to determine the presence of heroin in the substance: presumptive and confirmatory (Saferstein & Roy, 2020). The presumptive test allows one to assume that the illegal component might be present in the substance, but the results are not completely precise (Harper et al., 2017). The confirmatory test allows more detailed results, which can be obtained only in the laboratory using infrared spectroscopy or Gas Chromatograph-Mass Spectrometry (Harper et al., 2017). These methods feature the combination of qualitative and quantitative evaluation of the substance that are critical components of the investigation.
It is possible to state that the protocol of the scientific evaluation allows the specialist to measure the sample based on the necessary criteria. First, the forensic scientist would use the presumptive test in the field of crime to state that there is the possibility of heroin in the substance. Then, they would use the confirmatory test in the laboratory to separate the illegal drug from the substance and to give precise conclusions about the amount of heroin.
Forensic scientists glean the most critical characteristics from the drug sample while conducting qualitative and quantitative analyses. For example, the quantitative analysis allows them to state the precise amount of the drug in the sample, which influences the decision of the legal persecutor. Qualitative research gives information about the type of substance in the sample. Sometimes, several drugs are combined in one substance sample, which is impossible to understand without laboratory testing.
As it was already mentioned, there are several types of testing that forensic scientists use. Among them are screening and confirmation tests. The screening technique is the first step in the analysis that allows the forensic scientist to determine the presence of the drug, while the confirmation test aims at proving the results obtained from the first test (Alhefeiti et al., 2021). Both techniques have their benefits and limitations that determine their practical use. Screening test allows the scientist to select various types of drugs, but these results are superficial (Alhefeiti et al., 2021). The confirmation test has a higher sensitivity to the elements (Alhefeiti et al., 2021). In all cases, forensic scientists usually use both techniques to prove their hypothesis.
It is possible to illustrate the methods that are widely used in forensic science with the following lines from the article by Harper et al.:
The best methods for point-of-care drug testing are handheld infrared spectroscopy, Raman spectroscopy, and ion mobility spectrometry; mass spectrometry is the current gold standard in forensic drug analysis. It would be prudent for agencies or clinics that can obtain the funding to contact the companies that produce these devices to discuss possible usage in a harm reduction setting. Lower tech options, such as spot/color tests and immunoassays, are limited but affordable and easy to use (Harper et al., 2017, p. 52). This excerpt shows a certain degree of variations in the options available for forensic scientists depending on the laboratory opportunities they have. Qualitative and quantitative elements are still necessary in all cases. The comparatively significant number of tests available to forensic scientists allows them to choose the best solution in every case to achieve objective results.
It is vital to remember that the opinions that forensic scientists express are subject to scrutiny through the judicial process. Therefore, they need to pay much attention to the details that might seem insignificant at first sight. Forensic scientists should use a combination of analytical procedures when identifying a white powder containing heroin with a purity of 60% to ensure that accurate and reliable scientific results are obtained. The recommended method combines CI MS (Chemical Ionization and Mass Spectrometry) and EI (Electron Ionization) testing (Alhefeiti et al., 2021). This solution has a significantly higher level of precision compared to other techniques. Therefore, its use in forensic practice is justified from the perspective of the scientific method.
A forensic scientist would defend their scientific conclusions and opinions in a court of law using the objective results of the investigation. In all cases, forensic scientists should prepare for the court and have all the necessary data to prove their conclusions. There is a standard lab protocol that all forensic scientists should follow, and they must present it in court. The answer should be ethical, logical, and based on objective results to professionally defend the position of the forensic scientist.
References
Alhefeiti, M. A., Barker, J., & Shah, I. (2021). Roadside drug testing approaches. Molecules, 26(11), 3291. Web.
Harper, L., Powell, J., & Pijl, E. M. (2017). An overview of forensic drug testing methods and their suitability for harm reduction point-of-care services. Harm Reduction Journal, 14(1), 52. Web.
Saferstein, R., & Roy, T. (2020). Criminalistics: An introduction to forensic science. Pearson Education.