Spectrophotometric cocaine determination in a biphasic medium employing flow-batch sequential injection analysis

Area of Science:

• Analytical Chemistry
• Forensic Science

Background:

• Cocaine quantification is vital for Brazilian Federal Police to determine drug origin and traffic routes.
• Variable cocaine concentrations pose lethal risks due to potential overdose.
• Conventional methods like Gas Chromatography (GC-FID, GC-MS) are costly and not universally available in police labs.

Purpose of the Study:

• Develop a cost-effective flow-system procedure for cocaine determination.
• Utilize spectrophotometry with cobalt thiocyanate for cocaine analysis.
• Provide an accessible analytical method for police laboratories.

Main Methods:

• A flow-system procedure employing sequential injection analysis.
• Spectrophotometric detection using cobalt thiocyanate as a complexing reagent.
• An optic fiber sensor recorded absorbance at 630 nm.

Main Results:

• The method achieved detection and quantification limits of 29.4 mg L(-1) and 98 mg L(-1), respectively.
• A relative standard deviation of 4.9% was observed for solutions at 400 mg L(-1).
• The analytical throughput reached 12 determinations per hour with stable baselines.

Conclusions:

• A novel, cost-effective spectrophotometric method for cocaine quantification was successfully developed.
• This flow-system procedure offers a viable alternative to expensive chromatographic techniques for forensic applications.
• The method provides reliable and efficient cocaine analysis for law enforcement laboratories.