Rapid Analysis of Sugars Using Discrete Analyzers

Significance of the topic

Automated discrete photometric analyzers enable fast, reliable enzymatic quantification of common sugars (glucose, fructose, sucrose, lactose) across a wide variety of liquid matrices such as fruit juices, wines, musts and fermentation samples. Rapid sugar profiling supports process control, raw material inspection, quality assurance and label claim verification. The combination of enzymatic specificity, low reagent consumption and walk-away automation addresses routine laboratory needs for throughput, reproducibility and cost-efficiency.

Objectives and overview of the study

This work evaluated Thermo Scientific discrete analyzers (Gallery, Gallery Plus and Arena) and ready-to-use enzymatic reagent kits for routine sugar analysis. Objectives were to demonstrate method performance (linearity, precision), compare results with reference techniques (HPLC and FTIR), summarize operational features (throughput, automation) and outline practical advantages for routine laboratory implementation.

Materials and methods

Enzymatic reagent kits are supplied as ready-to-use liquid vials optimized for discrete analyzer dispensing and reaction volumes. Kits cover individual analytes and combinations: D-Glucose; D-Fructose; D-Glucose + D-Fructose; D-Glucose + D-Fructose + Sucrose; Sucrose (reported as Total Glucose); and Lactose (measured via glucose). Typical assay conditions: incubation at 37 °C, endpoint or kinetic measurement of NAD(P)H absorbance at 340 nm with a 600 nm side wavelength for verification, and an automated pre-dilution default of 1:50 to reduce matrix effects. Reagents are bar-coded and support automated calibration routines and reagent tracking. Linearity calibration routines use automated dilutions to add calibration points when needed.

Used instrumentation

• Thermo Scientific Gallery analyzer (discrete photometric analyzer).
• Thermo Scientific Gallery Plus analyzer (higher throughput variant).
• Thermo Scientific Arena analyzer (platform compatibility noted).
• Measurement optics: primary 340 nm photometric reading with 600 nm reference wavelength.

Main results and discussion

Method comparison and analytical performance:

• Method comparison versus HPLC and FTIR: correlation coefficients (r2) of 0.984 or better across studies comparing discrete analyzer results with HPLC and FTIR for glucose, fructose, sucrose and combination methods. Regression slopes were close to unity and small intercepts indicate good agreement across a broad concentration range.
• Linearity: methods showed broad linear ranges enabled by automated pre- and post-dilutions. Lactose linearity data (water-based standards) demonstrated excellent agreement between theoretical and measured concentrations.
• Precision: within-run coefficients of variation (CV) typically around 1%, improving at higher concentrations; total precision generally under 2% with within-run CVs as low as ~0.5% for D-glucose in favorable conditions.
• Measuring ranges (summarized): D-Glucose 0.1–160 g/L; D-Fructose 0.7–200 g/L; D-Glucose + D-Fructose 0.4–200 g/L; D-Glucose + D-Fructose + Sucrose 0.24–200 g/L; Sucrose (Total Glucose) 0.1–100 g/L; Lactose (Glucose) 0.05–15 g/L.
• Throughput and speed: analyzer throughput depends on model — approximately 200 photometric tests/hour for Gallery and up to 350 photometric tests/hour for Gallery Plus. The Gallery Plus can perform about 77 combined D-Glucose + D-Fructose + Sucrose tests per hour, with first results available in under 20 minutes for that assay.

Benefits and practical applications

Key operational advantages identified:

• Ready-to-use reagents and automated calibrations reduce manual handling, operator time and potential for pipetting errors.
• Discrete cell technology enables multiple assays on the same sample without method changeover, saving time and sample volume.
• Low reagent volumes and optimized kit sizes reduce cost per test; bar-coded vials and on-board reagent tracking improve traceability and inventory control.
• Automated dilutions and temperature-controlled reactions minimize matrix effects and improve method robustness across diverse sample types.
• Good agreement with HPLC and FTIR supports use of discrete analyzers as reliable routine alternatives or complementary tools in laboratories performing sugar analyses.

Future trends and potential applications

Trends and opportunities for discrete enzymatic sugar analysis include:

• Further expansion of multiplexed assays to increase the number of carbohydrate targets measured per sample without added workflow complexity.
• Integration with laboratory information management systems (LIMS) for improved data traceability and automated reporting in regulated environments.
• Miniaturization and reagent optimization to lower costs further and reduce waste, aligning with green chemistry goals.
• Combining discrete enzymatic results with spectroscopic or chromatographic techniques for orthogonal confirmation in high-value samples (e.g., regulatory or labeling disputes).
• Application growth beyond food and beverage (e.g., bioprocess monitoring, fermentation control in biotech) where rapid sugar monitoring supports process optimization.

Conclusion

Discrete photometric analyzers with ready-to-use enzymatic kits provide accurate, precise and high-throughput solutions for routine sugar analysis in complex liquid matrices. The methods exhibit wide linear ranges, strong correlation with HPLC and FTIR reference methods, low within-run and total imprecision, and operational advantages such as walk-away automation, reagent traceability and reduced cost per test. These attributes make discrete analyzers attractive for QA/QC, process monitoring and routine laboratory workflows requiring frequent sugar determinations.

References

1. Bergmeyer HU. Methods of Enzymatic Analysis. Verlag Chemie/Academic Press; 1974.
2. Jacobson JL. Introduction to Wine Laboratory Practices and Procedures. Springer; 2006.
3. International Organization of Vine and Wine. Compendium of International Methods of Analysis: Reducing substances, Method OIV-MA-AS311-01A.
4. Association of Official Analytical Chemists. Official Methods of Analysis: Glucose and Fructose in wine, AOAC Method 985.09 (enzymatic).