Chromatography, Detection, and Software Tools to Aid in the Exploration of Delta-8 THC Distillates

Importance of the Topic

Delta-8-tetrahydrocannabinol (Δ8-THC) derived from hemp-sourced CBD has surged in popularity amid unclear regulations and growing consumer demand. This synthetic conversion process can generate multiple byproducts and isomers, raising safety and labeling concerns. Comprehensive analytical methods are therefore critical to ensure product quality and consumer safety.

Objectives and Study Overview

The application brief aimed to:

• Characterize known and unknown cannabinoids in Δ8-THC distillates.
• Demonstrate the combined use of HPLC-PDA, single-quadrupole MS, and Empower™ software tools for peak identification.
• Highlight approaches to detect co-eluting compounds and isomeric species.

Methodology and Used Instrumentation

High-performance liquid chromatography (HPLC) coupled with photodiode array detection (PDA) and single-quadrupole mass spectrometry (MS) was used. Key instruments and software included:

• ACQUITY UPLC PDA Detector
• ACQUITY QDa Mass Detector
• Empower Chromatography Data System

A standard mixture of neutral cannabinoids was separated at 228 nm. Distillate samples (1 µg/mL injection) were analyzed to detect both targeted and unknown peaks.

Main Results and Discussion

Chromatographic separation of ten neutral cannabinoids resolved several Δ9-THC isomers alongside Δ8-THC. In distillate samples, Δ8-THC accounted for 66 % area. Multiple unknown peaks exhibited UV spectra similar to Δ8-THC and a base MS ion at m/z 315, suggesting structural isomers.
Library searching with PDA spectral libraries proposed (6aR,9S)-Δ10-THC and (6aR,9R)-Δ10-THC as best matches for unknown peaks eluting at 6.151 min and 6.530 min. Spectral contrast (match angles), retention time alignment, and peak purity analysis confirmed co-elution in some cases. In-source fragmentation experiments (cone voltages 15 V vs 45 V) generated diagnostic fragments (m/z 259, 193, 135, 123) consistent with authentic Δ10-THC standards, enhancing structural confirmation.

Benefits and Practical Applications

Key advantages of the combined approach:

• Enhanced confidence through dual PDA and MS detection.
• PDA spectral libraries allow isomer discrimination via retention time and spectral matching.
• Peak purity plots reveal co-eluting impurities.
• In-source fragmentation provides additional structural insight without tandem MS.

Future Trends and Opportunities

As novel cannabinoid analogues emerge, expanded spectral libraries including acid and neutral forms will be essential. Advances in high-resolution MS and software-driven chemometric tools may further resolve complex isomeric mixtures. Integration of orthogonal detection techniques and automation in data processing will streamline routine quality control and forensic analyses.

Conclusion

This work demonstrates that HPLC-PDA-MS coupled with Empower software effectively identifies known and unknown cannabinoids in Δ8-THC distillates. PDA library searching, peak purity evaluation, and in-source fragmentation collectively enhance confidence in isomer assignment and ensure comprehensive profiling of consumer products.

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