Analysis of Formaldehyde Using Post-Column Derivatization with Acetylacetone

Significance of the Topic

Formaldehyde is widely used in resin products and cosmetics preservatives but poses health risks and is strictly regulated in many regions.

Objectives and Overview of the Study

This study aimed to implement a reliable ultra high performance liquid chromatography procedure with post-column derivatization using acetylacetone for selective detection of trace formaldehyde in cosmetic samples.

Methodology and Instrumentation

The analysis employed a Shimadzu Nexera XR system equipped with:

• Autosampler SIL-40C XR
• Column oven CTO-40C
• Degassing unit DGU-403
• Chemical reaction chamber CRB-40 connected to reaction and cooling coils
• Pump LC-40B XR
• PDA detector SPD-M40 set at 414 nm

Separation used a Shim-pack GIST C18-AQ column (150 mm x 4.6 mm, 5 µm) with 6 mmol/L phosphate buffer at pH 2.1. Mobile phase flow was 1.0 mL per minute at 30 °C. Post-column reagent of acetylacetone and ammonium acetate was delivered at 0.5 mL per minute and reacted at 90 °C.

Main Results and Discussion

Calibration curves were linear (r2>0.9999) in the 0.05 to 1.0 mg/L range. Standard solutions in water and water/THF mixtures yielded sharp peaks without distortion. Cosmetic samples including skin lotion, shampoo and hair conditioner showed formaldehyde levels below the 0.05 mg/L quantitation limit. Spiked recovery tests demonstrated 97 to 102 percent recovery, confirming accuracy and matrix tolerance.

Benefits and Practical Applications of the Method

• Selective detection via derivatization reduces interference from sample impurities
• Low detection limit suitable for regulatory compliance testing
• Robust peak shapes in highly aqueous mobile phases
• Applicable to a variety of cosmetic matrices

Future Trends and Potential Applications

Anticipated developments include integration with mass spectrometry for structural confirmation, miniaturization of reaction systems, green analytical approaches and real-time online monitoring in manufacturing environments. Enhanced derivatization reagents may further improve sensitivity and selectivity.

Conclusion

The described HPLC post-column derivatization method offers a reliable, sensitive and selective approach for trace formaldehyde determination in cosmetic products complying with global regulations.

References

• Pharmaceutical Society of Japan Methods of Analysis in Health Science 2015
• Ministry of Health and Welfare Notification No 331 Japan 2000
• Regulation EC No 1223/2009 Annex III