Quality control of deodorant by nearinfrared spectroscopy

Significance of the topic

Personal care products require strict quality control to ensure safety, performance and regulatory compliance. Traditional methods for measuring pH, density, viscosity and aluminum content in deodorants are time-consuming and often involve chemical reagents and sample preparation. Near-infrared spectroscopy offers a rapid, reagent-free and non-destructive alternative capable of simultaneous multi-parameter analysis in seconds.

Objectives and overview of the study

This study aimed to develop and validate NIR spectroscopy models for at-line and offline determination of key quality attributes of deodorant formulations. Specifically, it focused on measuring pH, density, viscosity and aluminum content using a single spectral acquisition without any sample preparation.

Applied methodology

The analysis employed transflection-mode NIR measurements over the 1000–2250 nm range. Sixty deodorant samples were scanned with a 1 mm pathlength reflector and a 60 mm transflection vessel. Reference values were obtained by titration for aluminum, a pH meter for acidity, a viscometer for viscosity and a density meter for density. Chemometric models were built and evaluated using OMNIS Software.

Applied instrumentation

• OMNIS NIR Analyzer Solid (1000–2250 nm) with transflection vessel and 1 mm gap reflector
• pH meter
• Viscometer
• Density meter
• OMNIS Software with Quant Development module

Main results and discussion

Calibration models showed strong correlation with reference methods. Key performance metrics included:

• Aluminum content: R2=0.908, SEP≈0.14%
• Density: R2=0.979, SEP≈0.0023 g/mL
• Viscosity: R2=0.941, SEP≈133.7 cP
• pH: R2=0.832, SEP≈0.10

Validation demonstrated reliable predictions for routine quality control, with precision levels suitable for industrial monitoring.

Benefits and practical applications of the method

NIR spectroscopy accelerates QC workflows by delivering results in seconds, eliminates chemical reagents and reduces waste. The method is applicable directly on the production line (at-line) or in QC laboratories, enabling real-time decision making, cost savings and minimized downtime.

Future trends and potential applications

Advances may include integration of NIR with automation and process analytical technology (PAT), application to diverse cosmetic formulations and coupling with machine learning for enhanced predictive power. Real-time monitoring and control strategies are likely to expand, supporting Industry 4.0 objectives.

Conclusion

The validated NIR approach provides a fast, non-destructive and reliable tool for multi-parameter quality control of deodorants. Its implementation can streamline production and QC operations, offering a sustainable alternative to conventional analytical methods.