Photometric Determination of Iron in Pharmaceutical Formulations Using Double-Beam Direct Injection Flow Detector

Area of Science:

• Analytical Chemistry
• Spectrophotometry
• Flow Injection Analysis

Background:

• Accurate determination of iron in pharmaceuticals is crucial for quality control.
• Existing methods may be time-consuming or require large sample volumes.
• Development of automated, efficient analytical techniques is an ongoing need.

Purpose of the Study:

• To introduce a novel flow-through, double-beam, photometric detector with direct injection (double-DID) for pharmaceutical iron analysis.
• To establish and validate an automated analytical procedure for total iron determination.
• To assess the performance and applicability of the developed method in real-world pharmaceutical samples.

Main Methods:

• Utilized a double-DID photometric detector with paired LED diodes and a log ratio precision amplifier.
• Integrated the detector with solenoid micro-pumps for precise reagent and sample handling.
• Determined total iron as Fe(II) using 1,10-phenanthroline complexation and photometric detection.
• Optimized analytical conditions and validated the method according to standard procedures.

Main Results:

• Achieved a linear calibration range of 1-30 mg L^-1 with a limit of detection (LOD) of 0.5 mg L^-1.
• Demonstrated high throughput (90 samples/hour) and excellent repeatability (R.S.D. = 2%).
• Showcased minimal reagent and sample consumption (20 μL each) and low waste generation (approx. 540 µL/analysis).
• Obtained results consistent with manual UV-Vis spectrophotometry and manufacturer claims.

Conclusions:

• The proposed automated flow system provides a stable, sensitive, and efficient method for iron determination in pharmaceuticals.
• The double-DID detector offers advantages in terms of automation, reduced reagent consumption, and waste generation.
• The method is suitable for routine quality control analysis of iron in pharmaceutical products.