High speed analysis of DNPH-Aldehyde

Significance of the Topic

The accurate and rapid quantification of volatile carbonyl compounds is crucial across environmental monitoring, indoor air quality assessment, food safety evaluation and clinical diagnostics. These reactive aldehydes and ketones can pose health risks at trace levels, requiring sensitive, robust analytical protocols to ensure reliable data in regulatory, research and quality‐control settings.

Aim and Overview of the Study

This application note describes the development of a high‐speed reversed‐phase liquid chromatography (LC) method for the simultaneous analysis of thirteen DNPH‐derivatized carbonyl compounds. Leveraging Shimadzu’s Shim-pack XR-ODS column and Prominence-i LC-2030C 3D Plus system, the study aims to achieve baseline separation and quantitation within a 15-minute run.

Methodology and Instrumentation

This method employs derivatization of target analytes with 2,4-dinitrophenylhydrazine (DNPH) to improve stability and UV absorbance at 360 nm. Key instrumental details include:

• LC System: Prominence-i (LC-2030C 3D Plus)
• Column: Shim-pack XR-ODS, 75 mm × 4.6 mm I.D., 2.2 µm (P/N 228-41607-93)
• Mobile Phase A: Water/THF (8 / 2, v/v)
• Mobile Phase B: Acetonitrile with gradient from 20% to 60% B over 15 min
• Flow Rate: 1.5 mL/min
• Column Temperature: 40 °C
• Detection: UV at 360 nm
• Injection Volume: 10 µL

Results and Discussion

The optimized gradient achieved complete separation of all thirteen DNPH derivatives in under 15 minutes. Major analytes included formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, crotonaldehyde, 2-butanone, methacrolein, n-butyraldehyde, benzaldehyde, valeraldehyde, m-tolualdehyde and hexanaldehyde. The method demonstrated:

• Sharp peak shapes with resolution >1.5 for adjacent analytes
• Linear calibration (R² > 0.999) over typical environmental and industrial concentration ranges
• Reproducible retention times (%RSD < 0.5%) and peak areas (%RSD < 2%)

Benefits and Practical Applications

This LC–UV approach offers several advantages:

• High throughput suitable for large sample batches in QA/QC laboratories
• Robustness against matrix interferences owing to DNPH derivatization
• Cost-effective instrumentation, avoiding the need for mass spectrometry
• Wide applicability to environmental, food and clinical sample types after simple sample preparation

Future Trends and Opportunities

Emerging developments may further enhance carbonyl analysis workflows:

• Integration with tandem mass spectrometry for increased selectivity and sensitivity
• Automated on-line derivatization and sampling for real-time monitoring
• Microcolumn and UHPLC formats to reduce solvent consumption and analysis time
• Advanced data processing with machine learning to streamline peak identification and quantitation

Conclusion

The presented Shim-pack XR-ODS method on the Prominence-i LC-2030C 3D Plus delivers a fast, reliable and user-friendly solution for simultaneous analysis of DNPH-derivatized carbonyls. Its combination of speed, resolution and quantitative performance makes it well suited for environmental, industrial and research laboratories.

Reference

• Shimadzu Corporation. High speed analysis of DNPH-Aldehydes using Shim-pack XR-ODS and Prominence-i LC-2030C 3D Plus. First Edition: September 2022, ERAS-1000-0366.