Agilent Molecular Spectroscopy Compendium

Significance of Molecular Spectroscopy in Food Analysis

Modern food and agricultural industries require rapid, reliable, and non‐destructive analytical methods to ensure quality, safety, and authenticity. Molecular spectroscopy—particularly mid‐infrared (MIR), UV‐Vis, and fluorescence—offers detailed molecular fingerprints of complex food matrices, enabling the detection of adulteration, compositional analysis, and quantification of key quality traits.

Study Objectives and Overview

• Compile emerging applications of Agilent’s molecular spectroscopy instruments for food testing and safety.
• Demonstrate non‐target and target analyte screening in diverse food matrices.
• Highlight instrument capabilities, sampling interfaces, and software solutions for both laboratory and in situ analyses.
• Present case studies: adulteration detection in edible bird nests and milk, quality trait screening in tomatoes, compositional analysis of dairy powders, flours, sugars, and teas, acrylamide quantification in potato chips, pesticide authentication, phosphate determination, and leaf optical modeling for crop monitoring.

Methodology and Instrumentation

• Instruments:

• Handheld and portable FTIR analyzers (Agilent 4100 ExoScan, 4200 FlexScan, 4500, 5500) equipped with diffuse reflectance, DialPath, and diamond ATR sampling interfaces.
• Benchtop FTIR spectrometers (Cary 630, Cary 660, Cary 610 microscope) using diamond ATR and transmission accessories.
• UV‐Vis spectrophotometer (Cary 60) with concentration application software.
• Fluorescence spectrometer (Cary Eclipse) for sensitive emission measurements.

• Sampling Technologies:

• ATR—single and multi‐reflection diamond for solids, liquids, powders.
• DialPath—fixed‐path transmission for quick liquid analysis.
• Diffuse reflectance—for non‐destructive screening of powders and granules.

• Data Analysis:

• Intuitive MicroLab Mobile FTIR software for on‐board methods, library matching, pass/fail results, and quantification.
• Partial least squares regression (PLSR) and chemometric modeling for trait estimation (Brix, pH, titratable acidity, sugars, acids) and contaminant quantification (urea, whey, hydrogen peroxide).
• Cary 1/3 Concentration Application for UV‐Vis assays of phosphorus and other colorimetric methods.

Main Results and Discussion

• Edible Bird Nest Authentication:
◦ Diffuse reflectance FTIR (4100 ExoScan) identified calcium carbonate, salt, sugars, MSG adulterants via characteristic bands (e.g., 1410, 873 cm⁻¹ for carbonates; 1050, 980, 905 cm⁻¹ for sucrose).
◦ On‐board quantitative methods provided real‐time pass/fail and adulterant identity.
• Tomato Quality Screening:
◦ Handheld 4200 FlexScan FTIR and benchtop Excalibur 3100 enabled PLSR models for Brix, pH, titratable acidity, glucose, fructose, citric acid with R up to 0.92.
◦ Field‐portable analysis reduced sample prep and delivered in situ results.
• Dairy Powder QA/QC:
◦ Cary 630 ATR‐FTIR distinguished milk protein powders (α‐lactalbumin, β‐lactoglobulin, WPI, WPC) via unique amide, carbohydrate, and lipid bands.
◦ Non‐destructive, no‐prep method at receiving dock or production line.
• Flour, Sugar, and Tea Authentication:
◦ ATR‐FTIR spectra library matching identified various flours (gluten‐free, grain types), sugars (glucose, sucrose, lactose, protein‐based sweeteners), and teas (green, black, oolong) within seconds.
• Milk Adulteration Screening and Quantification:
◦ DialPath FTIR screening on 5500/4500 FTIR detected 3–50% dilution.
◦ ATR‐FTIR of chloroform‐extracted dry films quantified whey, urea, synthetic milk, urine, H₂O₂ with SEP <0.5 g/L.
• Pesticide Authentication:
◦ Portable 4500 FTIR with ATR matched banned or counterfeit pesticides (chlordane isomers, aldrin, lindane, campheclor) against spectral libraries in <1 minute.
• Acrylamide in Potato Chips:
◦ Cary 630 ATR‐FTIR method on chip cakes yielded SEP ~75 μg/kg, comparable to LC‐MS/MS reference, enabling rapid on‐site assessment.
• Phosphorus in Hydroponics:
◦ Cary 1 UV‐Vis with concentration application quantified P at 7 mg/L via vanadomolybdate and stannous chloride colorimetry, with minimal interference.
• Leaf Optical Modeling:
◦ Cary 500 spectrophotometer measured leaf reflectance/transmittance of cereals; validated the PROSPECT model accuracy (R² >0.92 for water, >0.78 for chlorophyll) and demonstrated potential for hyperspectral crop monitoring.

Benefits and Practical Applications

• Rapid, solvent‐free methods reduce analysis time (<2 minutes) and costs.
• Portable and handheld instruments enable point‐of‐sample analysis: fields, docks, mobile labs.
• On‐board software allows unskilled operators to obtain reliable qualitative and quantitative results.
• Enhanced supply‐chain integrity: real‐time screening prevents adulterated ingredients from entering production.
• Supports QA/QC, R&D, and regulatory compliance across food, agriculture, and related industries.

Future Trends and Potential Uses

• Integration of mid‐IR spectroscopy with UAV and satellite hyperspectral platforms for large‐scale crop health monitoring.
• Expansion of application libraries and chemometric models for non‐target screening of emerging contaminants and food fraud markers.
• Automation and AI‐driven data analysis for continuous, real‐time quality control in smart manufacturing and precision agriculture.
• Miniaturization and ruggedization of spectrometers for extreme environments (on‐site feedlots, marine aquaculture, remote farming).
• Coupling with chromatography and mass spectrometry for comprehensive multi‐modal food safety assessments.

Conclusion

Agilent’s suite of molecular spectroscopy instruments—handheld, portable, and benchtop FTIR, UV‐Vis, and fluorescence spectrometers—provides a versatile, high‐throughput toolbox for the modern food and agriculture industries. By leveraging turnkey sampling interfaces, intuitive software, and robust chemometric methods, these technologies deliver fast, accurate, and actionable insights into food quality, safety, and authenticity from farm to fork.

References

1. P. M. Santos et al., “Application of handheld and portable infrared spectrometers in bovine milk analysis,” J. Agric. Food Chem., vol. 61, no. 6, pp. 1205–1211, 2013.
2. Agilent Technologies, “Agilent’s FTIR family—lab results, anywhere you want,” Pub. 5991-1405EN, 2012.
3. H. Ayvaz and L. E. Rodriguez-Saona, “Screening acrylamide in potato chips by portable FTIR,” J. Agric. Food Chem., in press.
4. S. Jacquemoud and F. Baret, “PROSPECT: A model of leaf optical properties spectra,” Remote Sens. Environ., vol. 44, pp. 281–292, 1990.
5. F. Baret and T. Fourty, “Estimation of leaf water content and specific leaf weight from reflectance and transmittance measurements,” Agronomie, vol. 17, pp. 455–464, 1997.