Verify samples quickly - Using reference samples and automated workflows

Significance of the topic

The application note describes a routine but impactful use of Fourier-transform infrared (FTIR) spectroscopy: spectral comparison of unknown samples against known reference materials for identity verification and quality control. Rapid, reproducible spectral matching is critical in incoming materials inspection, forensic identification, intellectual property verification, and routine QC in production environments. Automated, standardized workflows reduce operator variability and increase laboratory throughput while preserving traceability of decisions.

Objectives and overview of the study

The document demonstrates how the OMNIC Paradigm software implements a QCheck correlation-based comparison and how users can convert a recorded spectral processing history into an automated workflow. The example shown uses a polystyrene reference to verify a plastic sample, illustrating visual overlay, numerical correlation scoring, and an automated workflow that repeats measurements, exports results, and manages background collection to streamline batch analysis.

Methodology

• Spectral comparison metric: Correlation score (0–100), where higher values indicate closer spectral similarity; scores ≥95 are typically considered strong matches in many laboratories.
• QCheck function: Computes correlation between a sample spectrum and one or more reference spectra. Users can restrict spectral regions, adjust resolution, vary signal averaging, and set pass/fail thresholds to match application needs.
• Workflow generation: The OMNIC Paradigm software converts the spectral processing history (record of data acquisition, QCheck execution, and report generation) into an automated sequence of steps (tiles). Users can insert loops (Repeat tiles), background collection strategies, export steps, and exit conditions to support batch processing.
• Example workflow elements: Single background measurement reused for subsequent samples, a repeat loop for up to 20 samples, an export tile to append results to a text file (readable in Excel), and an exit tile to stop early if fewer samples remain.

Instrumentation used

The note references use of Thermo Fisher Scientific hardware and software components. Key instrumentation and software elements mentioned are:

• FTIR spectrometer platform: Nicolet Summit (with integrated touchscreen).
• Sampling accessory: Everest Diamond ATR (installed in the Nicolet Summit).
• Software: OMNIC Paradigm (includes QCheck and workflow capabilities).

These components enable ATR sampling, spectral acquisition, on-instrument interaction, and automated data processing and reporting.

Main results and discussion

• Visual overlay of sample and polystyrene reference showed strong agreement in band positions and intensities; QCheck calculated a correlation of 99.81 for the example, indicating a very close match.
• QCheck offers flexibility to tailor the comparison: limiting spectral regions improves sensitivity to relevant differences; adjusting resolution and averaging balances spectral detail against signal-to-noise and throughput; defining a pass/fail correlation threshold enforces QC criteria.
• Automated workflows capture the exact sequence of processing steps, promoting reproducibility and enabling batch analysis without repetitive manual intervention. Workflows also standardize reporting and export formats for downstream record-keeping.
• Reusing a single background spectrum across multiple sample runs was presented as a time-saving strategy when instrument and environmental stability permit, but users should consider potential bias if background conditions change.

Benefits and practical applications of the method

• Fast verification of material identity for incoming inspection and production QC, with quantitative correlation scores that facilitate objective pass/fail decisions.
• Forensic and intellectual property contexts benefit from documented, reproducible spectral comparisons and report generation.
• Automated workflows reduce operator-dependent variability, increase sample throughput, and create audit-ready exports compatible with spreadsheet review.
• Customization options (spectral regions, resolution, averaging) allow tailoring to diverse sample matrices and detection of subtle chemical differences (contaminants, copolymers, additives).

Future trends and potential uses

• Integration with laboratory information management systems (LIMS) and cloud-based data platforms to centralize spectral libraries, audit trails, and automated decision-making.
• Machine learning augmentation of spectral matching that goes beyond linear correlation metrics to identify systematic deviations, classify mixtures, or predict composition percentages.
• Standardized, validated workflows for regulated environments (pharmaceuticals, forensics) to meet audit and accreditation requirements while preserving analytic flexibility.
• Expanded automation: robotics for sample handling combined with FTIR workflows to fully automate high-throughput QC lines.

Conclusion

The application note illustrates a practical implementation of FTIR-based identity verification using a correlation metric (QCheck) combined with automated workflows (OMNIC Paradigm). The approach delivers rapid, reproducible pass/fail decisions suitable for QC, forensic, and IP verification contexts. Workflow automation and configurable comparison parameters improve consistency and throughput, while instrument choices (ATR accessory, touchscreen-enabled spectrometer) facilitate routine use. Laboratories should balance throughput strategies (e.g., shared backgrounds) with control measures to avoid introducing bias.

References

• Thermo Fisher Scientific. 2019. Using reference samples and automated workflows. Application Note FL53203_E.