One of the most practically significant challenges in kratom science is a straightforward one: reliably determining what is actually present in a given sample, and at what concentration. This is not a trivial problem. Kratom alkaloids are structurally similar compounds that can be difficult to distinguish without precise analytical tools. Commercial kratom products have been found to vary substantially from their labelled specifications. The absence of mandatory testing standards in most jurisdictions means that product quality control is highly variable.
This article provides an educational overview of the primary analytical methods used to identify and quantify kratom alkaloids, what each method measures, why it is used, and what published studies have found when applying these methods to commercial products.
Why Analytical Characterisation Is Foundational
Any scientific claim about the effects of a kratom alkaloid is only as reliable as the characterisation of the material used to generate that claim. A study examining the pharmacological effects of mitragynine using a sample that contains variable proportions of other alkaloids, or that contains less mitragynine than assumed, produces findings that cannot be reliably interpreted or replicated.
The same principle applies to commercial products. A product labelled as containing a specific concentration of 7-hydroxymitragynine that actually contains a different concentration represents not just a consumer protection issue but a fundamental uncertainty about what users are actually consuming. Published surveys of commercial kratom products have documented this problem extensively.
High-Performance Liquid Chromatography (HPLC)
HPLC is the most widely used analytical method for kratom alkaloid quantification in both research and quality control settings. It is a separation technique that passes a liquid sample through a column packed with a stationary phase material, separating mixture components based on their differential interaction with the stationary and mobile phases.
How It Works
A kratom extract is dissolved in an appropriate solvent and injected into the HPLC system. The mobile phase, typically a mixture of aqueous buffer and organic solvent, carries the sample through the column. Different alkaloids travel through the column at different rates, emerging (eluting) at different times. A detector at the column outlet measures a signal for each compound as it elutes.
Detection Methods
UV-Vis detection (HPLC-UV) is the most common approach for kratom alkaloids. Mitragynine and its derivatives absorb ultraviolet light at characteristic wavelengths (around 228 and 295 nm), producing a measurable signal proportional to concentration. UV detection is straightforward and relatively inexpensive but cannot definitively confirm molecular identity, two compounds with similar UV absorption and elution times could be confused.
Diode array detection (HPLC-DAD) extends UV detection by recording the full UV-Vis absorption spectrum of each peak, providing an additional layer of identification confidence beyond retention time alone.
Liquid Chromatography-Mass Spectrometry (LC-MS)
LC-MS combines the separation power of liquid chromatography with the identification power of mass spectrometry. After compounds are separated by the LC column, they enter a mass spectrometer that measures their mass-to-charge ratio (m/z), a property that, combined with fragmentation patterns, provides definitive molecular identification.
Why LC-MS Is the Gold Standard
Mass spectrometric detection provides identification confidence that UV detection alone cannot match. Mitragynine and 7-hydroxymitragynine differ by only 16 atomic mass units (a single oxygen atom), a difference that LC-MS can readily resolve and confirm. Tandem mass spectrometry (LC-MS/MS) adds a second round of fragmentation, generating compound-specific fragmentation patterns that serve as molecular fingerprints.
LC-MS methods have been validated for simultaneous quantification of multiple kratom alkaloids including mitragynine, 7-hydroxymitragynine, speciogynine, paynantheine, and speciociliatine in a single analytical run. This multi-alkaloid quantification capability is essential for fully characterising the composition of kratom preparations.
Gas Chromatography-Mass Spectrometry (GC-MS)
GC-MS was used in early kratom alkaloid research before LC-MS methods were developed. It separates compounds in the gas phase (rather than liquid phase) and couples this separation with mass spectrometric detection. Because many kratom alkaloids are thermally labile or not sufficiently volatile for gas-phase analysis without chemical modification, GC-MS typically requires a derivatisation step to make alkaloids amenable to analysis.
GC-MS remains used in some forensic toxicology settings for kratom alkaloid detection in biological samples, but has largely been superseded by LC-MS methods for dedicated kratom product analysis.
Nuclear Magnetic Resonance (NMR) Spectroscopy
NMR spectroscopy probes the magnetic properties of atomic nuclei to determine molecular structure. It is the definitive method for structural confirmation of isolated compounds, when a semi-synthetic process produces a new compound, NMR is used to verify that the correct structure has been produced.
For 7-hydroxymitragynine specifically, NMR spectroscopy was central to confirming its molecular structure when it was first isolated and characterised. Proton NMR (1H NMR) and carbon NMR (13C NMR) provide complementary information about the hydrogen and carbon framework of the molecule. Two-dimensional NMR techniques can resolve the three-dimensional arrangement of atoms, important for confirming the stereochemistry of compounds like kratom alkaloids, which have multiple stereocentres.
NMR is less suitable for routine quantitative analysis of commercial products due to cost, instrument access, and throughput limitations, but it remains the reference method for structural identity confirmation.
What Commercial Product Testing Has Found
Multiple published studies have applied these analytical methods to commercial kratom products, powders, capsules, extracts, and teas, available in the United States and internationally. The findings have been consistent in documenting substantial quality concerns:
- A 2020 study published in Drug Testing and Analysis analysed 57 commercial kratom products and found mitragynine concentrations ranging from undetectable to over 20 mg per gram of product, a more than 20-fold range across products making similar claims
- 7-Hydroxymitragynine concentrations were frequently below labelled amounts; some products with high 7-OH label claims contained negligible detectable 7-OH
- Some commercial products contained undisclosed adulterants, including other plant alkaloids not native to Mitragyna speciosa
- Product-to-product variability within the same brand has been documented, indicating inconsistency in manufacturing rather than just variability between brands
These findings underscore the scientific importance of analytical verification. In a product category lacking mandatory testing requirements, the published research functions as the primary evidence base for understanding actual product composition.
Accreditation and Reference Standards
The reliability of analytical testing is only as good as the quality systems surrounding it. Key quality indicators for laboratory alkaloid testing include:
- ISO/IEC 17025 accreditation: the international standard for testing and calibration laboratory competence, covering both technical requirements and management system requirements
- Validated analytical methods: methods that have been formally demonstrated to be fit for purpose, including assessments of precision, accuracy, linearity, limits of detection and quantification, and selectivity
- Certified reference standards: analytically characterised reference compounds with documented purity and traceability, used to calibrate quantitative measurements
- Chain of custody documentation: records demonstrating sample integrity from collection through analysis
Certified reference standards for mitragynine and 7-hydroxymitragynine are available from accredited suppliers including Cayman Chemical and Sigma-Aldrich, enabling reliable quantitative calibration for research and quality control applications.