Content determination of explosive precursors and narcotic salts using 35Cl-nuclear magnetic resonance

Sammanfattning: Explosive precursors and narcotic salts are chemicals contributing to an undesirabledevelopment of the Swedish society, both in terms of criminal activities and harm to the environment. Reducing the illegal use of these chemicals is important in the work towards a safer society. National Forensic Centre (NFC) is the state agency responsible for forensic investigations for the Swedish Police Authority. The Drug Analysis and ChemistryTechnology section at NFC were both in need for an accurate quantification method to determine the content of Cl in narcotic salts and explosive precursors. Nuclear magnetic resonance (NMR) spectroscopy was assessed to be suitable since a recently published article had shown applicability of 35Cl NMR on narcotic salts. The aim of the method was to find the most appropriate parameter settings for the compounds of interest, including operating frequency, 90° pulse length, number of scans, relaxation time, and relaxation delay. To ensure a reliable and accurate method, the following validation parameters were studied; linearity, limit of detection (LOD), limit of quantification (LOQ), intermediate precision, trueness, repeatability, and ruggedness. Dimethyl sulfoxide (d6-DMSO) was chosen as the preferredsolvent for the Drug Analysis section since it is a common solvent for their 1H-NMR analysis. For explosive precursors results showed advantages of using deuterium oxide (D!O) as solvent, considering accuracy, solubility and shorter analysis time.Concluding, the chosen criteria of signal-to-noise (S/N) ratio >6 resulted in an LOQ of around 0.15g/L, though this was dependent upon the number of scans utilized. Successful pulse length experiments determined exact 90° pulse lengths for each sample and solvent combination. The longitudinal relaxation time T1 was also successfully determined, and since it was multiplied with five to ensure complete relaxation to stable state the relaxation delay D1was assumed as an insignificant parameter for the determination of chloride. Quantification was based upon the pulse-length based concentration determination (PULCON) using an external standard. The ruggedness can be studied additionally by another experienced operator (since trueness was strongly dependent upon the preparation of the external standard solution). The method displayed good linearity over the mass range normally utilized in such quantifications. The conclusion drawn in the thesis is that the method shows great promise but additional analyzes are still required before implementation at NFC