This Colombian metrology paper describes the development and certification of INM-040-1, a pulverized lyophilized cannabis leaf CRM for arsenic, cadmium, and lead. The study is a laboratory quality-assurance tool, not an environmental occurrence survey.
Key numbers
Certified values for INM-040-1 (Table 5; mg/kg = µg/g dry weight; expanded uncertainty k=1.97, approximately 95% CI): [VERIFY table check]
| Analyte | Certified value | Expanded uncertainty |
|---|---|---|
| total arsenic (tAs) | 0.344 mg/kg | ± 0.030 mg/kg |
| cadmium (Cd) | 0.335 mg/kg | ± 0.045 mg/kg |
| lead (Pb) | 0.655 mg/kg | ± 0.055 mg/kg |
These values are specific to the Colombian cannabis leaf material used to prepare the CRM. They reflect the contamination level of the source plant tissue and are not intended as occurrence estimates for retail cannabis. The CRM was validated against NIST SRM 1515 (apple leaves), 1573a (tomato leaves), 3232 (kelp powder), 3254 (hemp seed), and 1575a (pine needles).
Methods (brief)
Combined ICP-MS, GF-AAS (cadmium, lead), and HG-AAS (arsenic); homogeneity and stability testing per ISO Guide 35; certified values assigned by interlaboratory consensus; expanded uncertainty at k=1.97.
Evidence fitness
This paper is a metrological tool for laboratory method validation for cannabis leaf analysis. It provides no occurrence data for retail cannabis flower. The CRM certified values indicate that the specific Colombian leaf material contains detectable arsenic, cadmium, and lead at concentrations in the range seen in other cannabis plant studies, but the material was selected and prepared to serve as a matrix reference, not to represent typical market contamination. Cannabis leaves are not the same matrix as inflorescences; leaf and inflorescence concentrations differ in some studies. This source is catalogued here as analytical context.
Limitations
Not an occurrence survey. CRM matrix is cannabis leaves, not inflorescences. Colombian-grown material under unstated soil conditions.
Related evidence
Update history
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