Comparison of SPELEC RAMAN and standard Raman microscopes

Importance of the Topic

Raman spectroscopy coupled with electrochemistry enables in-depth molecular analysis crucial for materials science, energy research, and quality control. Traditional confocal Raman microscopes offer high spatial resolution but may misrepresent heterogeneous samples due to their small spot size. SPELEC RAMAN addresses these limitations by using a larger laser spot, integrated spectroelectrochemical capabilities, and a compact, portable design.

Objectives and Study Overview

This study compares a standard confocal Raman microscope with the SPELEC RAMAN instrument in measuring single-walled carbon nanotubes (SWCNTs). The goal is to evaluate sampling representativeness, measurement reproducibility, laser power handling, and overall operational versatility.

Methodology

SWCNT samples were analyzed at four distinct positions using a standard Raman microscope and then characterized in bulk with a single measurement using SPELEC RAMAN. The intensity ratio between D and G bands (ID/IG) was calculated for each spectrum to assess sample homogeneity and reproducibility. Additional tests evaluated laser power distribution and probe adaptability to various electrochemical cells.

Used Instrumentation

• SPELEC RAMAN instrument (785 nm laser, integrated potentiostat/galvanostat, spectrometer covering 35–3000 cm⁻¹)
• Raman Probe with 190 µm spot diameter and 8 mm focal distance
• Raman spectroelectrochemical cells for screen-printed and conventional electrodes
• DropView SPELEC software for synchronized electrochemical and spectroscopic data acquisition and analysis
• Standard confocal Raman microscope (spot sizes 0.5–10 µm)

Key Results and Discussion

• Standard microscope measurements yielded ID/IG ratios of 0.679, 0.843, 0.837, and 0.448 (average 0.702; RSD 26.44%), indicating sampling variability.
• SPELEC RAMAN produced a single measurement with ID/IG = 0.701, matching the microscope average. Four replicates on SPELEC RAMAN gave an average ID/IG = 0.718 with RSD 1.97%, demonstrating high reproducibility.
• The larger focal area allowed safe use of higher laser power without sample damage.
• Universal fiber connectors and modular cell design supported flexible integration across different setups and compatibility with existing microscopes.
• Compact size (25 × 24 × 11 cm) and integrated hardware/software simplified operando measurements in standard lab environments and gloveboxes.

Benefits and Practical Applications of the Method

• Representative bulk analysis from a single acquisition reduces time and cost.
• High reproducibility enhances data reliability and confidence.
• All-in-one spectroelectrochemical design eliminates additional hardware or software requirements.
• Portable instrumentation broadens on-site and in-situ analytical capabilities.

Future Trends and Potential Applications

Advances in customizable probes and cell configurations will enable targeted studies in catalysis, batteries, and biomedical sensors. Integration with automated workflows and remote monitoring platforms may facilitate real-time industrial quality control. Combining Raman spectroelectrochemistry with complementary spectroscopic techniques could deepen mechanistic insights and expand analytical scope.

Conclusion

SPELEC RAMAN outperforms traditional Raman microscopy by delivering representative, reproducible, and versatile spectroelectrochemical measurements with minimal setup complexity. Its portable form factor and intuitive software streamline advanced analytical workflows across diverse research and industrial settings.

Reference

• Application Note AN-RA-002: The carbon battle characterization of screen-printed carbon electrodes with SPELEC RAMAN
• Application Note AN-RA-003: In situ, fast and sensitive: Electrochemical-SERS with screen-printed electrodes
• Application Note AN-RA-005: Characterization of single-walled carbon nanotubes by Raman spectroelectrochemistry
• Application Note AN-RA-006: New strategies for obtaining the SERS effect in organic solvents
• Application Note AN-RA-007: Enhancement of Raman intensity for the detection of fentanyl
• Application Note AN-RA-008: Easy detection of enzymes with the electrochemical-SERS effect