Analysis of Food Preservatives Using the Agilent 1290 Infinity II LC

Significance of the topic

The reliable quantification of food preservatives is essential for ensuring product safety and regulatory compliance. Conventional HPLC methods are robust but often time-consuming and solvent-intensive. Ultra-high-performance liquid chromatography (UHPLC) addresses these limitations by enabling faster separations, higher resolution, and reduced solvent and sample consumption.

Objectives and overview of the study

This work demonstrates the transfer of a standard HPLC method for seven common food preservatives to UHPLC using the Agilent 1290 Infinity II LC system. Key goals included:

• Minimizing analysis time while maintaining chromatographic performance
• Reducing solvent and sample usage
• Comparing precision, linearity, detection limits, and resolution between HPLC and UHPLC configurations

Methodology and instrumentation used

The analytical system consisted of:

• Agilent 1290 Infinity II High-Speed Pump
• Agilent 1290 Infinity II Multisampler
• Multicolumn Thermostat
• Diode Array Detector (Max-Light cell)

Software: Agilent OpenLAB CDS ChemStation Edition C.01.07.
Mobile phases: A) Water with 20 mM ammonium formate (pH 4.4), B) Acetonitrile.
Columns and conditions:

1. HPLC: ZORBAX SB-C18, 4.6×150 mm, 5 μm; 17 min cycle; 1 mL/min; 5 μL injection; 40 °C.
2. UHPLC (speed): ZORBAX RRHT SB-C18, 4.6×50 mm, 1.8 μm; 5.5–10.5 min cycle; 1 mL/min; 5 μL injection; 40 °C.
3. UHPLC (ultrafast): ZORBAX RRHD SB-C18, 2.1×50 mm, 1.8 μm; 1–2 min cycle; 1.5 mL/min; 1.25 μL injection; 40 °C.

Main results and discussion

• Time savings: Cycle time reduced from 27 min (HPLC) to 10.5 min (UHPLC, 4.6×50 mm) and to 2 min (UHPLC, 2.1×50 mm), corresponding to >60% and >90% reductions.
• Solvent usage: Nearly 90% reduction with the fastest UHPLC method.
• Sample volume: 75% lower injection volume in the ultrafast UHPLC.
• Precision: Retention time RSD below 0.1% and area RSD below 0.5% across all methods.
• Linearity: Correlation coefficients >0.9999 for six of seven preservatives in all configurations.
• Detection limits: Comparable LOD/LOQ in fast UHPLC; five preservatives exhibited improved sensitivity compared to HPLC.
• Resolution: Baseline separation maintained despite faster gradients and smaller column dimensions.

Benefits and practical applications

• High-throughput quality control in food, beverage, and cosmetic testing laboratories.
• Cost savings through reduced solvent consumption and faster sample throughput.
• Smaller sample volumes enable conservation of standards and limited or precious samples.
• Regulatory compliance supported by excellent precision, linearity, and detection performance.

Future trends and applications

Emerging directions include integration of UHPLC with high-resolution mass spectrometry for broadened compound coverage, development of sub-1 μm particle columns for even faster separations, and greener analytical protocols emphasizing minimal solvent use and on-line sample preparation.

Conclusion

The transfer from HPLC to UHPLC on the Agilent 1290 Infinity II LC system achieved dramatic reductions in analysis time, solvent, and sample consumption while preserving or enhancing chromatographic performance. This approach supports efficient, sensitive, and environmentally responsible analysis of common food preservatives.

References

1. Gratzfeld-Huesgen A, Schuster R. HPLC for Food Analysis. Agilent Technologies Primer; 2001.