Liquid-liquid microextraction without phase separation in a multicommuted flow system for diltiazem determination in...

Area of Science:

• Analytical Chemistry
• Pharmaceutical Analysis

Background:

• Accurate quantification of anti-hypertensive drugs like diltiazem is crucial for therapeutic monitoring.
• Traditional methods for drug analysis often involve large solvent volumes and complex procedures.

Purpose of the Study:

• To develop a rapid and efficient liquid-liquid microextraction method for diltiazem determination.
• To implement the method in a multicommuted flow system for enhanced automation and reduced solvent consumption.

Main Methods:

• Liquid-liquid microextraction without phase segmentation using ion pair formation with bromothymol blue.
• Detection via fiber-optics spectrophotometry in a flow system.
• Optimization of parameters including pH and reagent concentrations.

Main Results:

• A linear response for diltiazem was observed in the range of 9–120 μmol L⁻¹, with a low detection limit of 0.9 μmol L⁻¹.
• The method demonstrated high precision (CV=0.6%), a sampling rate of 78 determinations per hour, and an extraction efficiency of 61%.
• Significant reduction in chloroform consumption (50 μL vs. 10 mL) and waste volume (380 μL) was achieved.

Conclusions:

• The developed method offers a sensitive, rapid, and environmentally friendly approach for diltiazem analysis.
• The multicommuted flow system coupled with microextraction is effective for pharmaceutical sample analysis.
• Results align with reference methods, validating its applicability in quality control.