Measurement of Impurities in Ethanol Using UV-Vis Spectrophotometer

Importance of the topic

Ethanol demand for disinfection has risen sharply due to public health concerns. Ensuring its purity is critical when ethanol is used in medical and industrial settings. Monitoring low level impurities safeguards product quality and compliance with pharmacopoeial standards.

Objectives and overview of the study

This study demonstrates a spectrophotometric method to quantify nonvolatile impurities in ethanol following criteria of the Japanese, European, and US Pharmacopoeias. It aims to automate pass fail evaluation of absorbance within defined ultraviolet ranges.

Methodology and instrumentation

Analyses were performed on a Shimadzu UV-1900i UV-Vis spectrophotometer with LabSolutions UV-Vis software. A 5 cm path length square cell and water blank were used. Spectra were scanned from 235 to 340 nm at 0.5 nm intervals at medium speed and 1 nm slit width. Automated spectral evaluation functions applied point pick and maximum value criteria.

Main results and discussion

The absorbance of anhydrous ethanol met all pharmacopoeial limits not greater than 0.40 at 240 nm 0.30 between 250–260 nm and 0.10 between 270–340 nm. Spectra were smooth with no observable peaks or shoulders. Pass fail judgments were generated automatically with failed samples clearly flagged by red evaluation lines.

Benefits and practical applications

Automated spectral evaluation significantly reduces operator time and minimizes human error. The method ensures rapid reproducible compliance testing for ethanol purity in pharmaceutical and industrial laboratories.

Future trends and applications

Further integration of advanced software algorithms and artificial intelligence may enhance detection of trace impurities. Expansion of automated spectrophotometric workflows across other solvents and pharmaceutical analyses is anticipated.

Conclusion

The UV-1900i combined with LabSolutions UV-Vis delivers an efficient reliable approach for ethanol impurity assessment in line with international pharmacopoeias improving throughput and data integrity.

Reference

• Japanese Pharmacopoeia European Pharmacopoeia United States Pharmacopeia
• Shimadzu UV-1900i UV-Vis Spectrophotometer Operation Manual