Sample Preparation

Patricia Atkins is a Senior Applications Scientist with SPEX CertiPrep and a member of both the AOAC and ASTM committees for cannabis.

Articles

Here we continue the discussion of energy and elements used in atomic spectroscopy by looking at one of the most commonly used analytical techniques in the elemental analytical laboratory—inductively coupled plasma-atomic emission spectroscopy (ICP-AES).

Energy and Elements, Part II: A Closer Look at ICP

This article addresses the US Department of Agriculture’s hemp testing rules and what laboratories should know regarding hemp testing. The author provides a short tutorial for laboratories and includes a section how laboratory information management systems (LIMS) can help.

Delineating the Nuts and Bolts of the USDA’s Hemp Testing Rules

This article outlines why multiple testing modes are important, what to look for in third party test providers, and how a cultivator can evaluate these potential providers both at the outset and in an ongoing manner for accuracy and reliability.

Cannabis Cultivation Quality Assurance 2.0:  Starting Clear, Staying Clean

Brian C. Smith, PhD, is Founder, CEO, and Chief Technical Officer of Big Sur Scientific. He is the inventor of the BSS series of patented mid-infrared based cannabis analyzers. Dr. Smith has done pioneering research and published numerous peer-reviewed papers on the application of mid-infrared spectroscopy to cannabis analysis, and sits on the editorial board of Cannabis Science and Technology. He has worked as a laboratory director for a cannabis extractor, as an analytical chemist for Waters Associates and PerkinElmer, and as an analytical instrument salesperson. He has more than 30 years of experience in chemical analysis and has written three books on the subject. Dr. Smith earned his PhD on physical chemistry from Dartmouth College. Direct correspondence to: 

In part I of this series on statistical concepts related to cannabis analysis, we introduce the normal distribution, standard deviation, and how to calculate precision and accuracy.

Statistics for Cannabis Analysis, Part I: Standard Deviation and Its Relationship to Accuracy and Precision

The inter-laboratory variation problem still exists, which means laboratory certification is necessary, but not sufficient to guarantee your samples are analyzed properly. Here, Smith offers suggestions to help improve the situation.

Laboratory Accreditation: Is It Enough to Guarantee Your Samples Are Analyzed Correctly?

Why the USDA’s requirements on what part of the plant to sample and how to obtain samples from the field are rife with problems and how to solve them.

Hemp Testing Insanity IV:  Problems with the USDA’s Hemp Sampling Rules

This work describes an inductively coupled plasma-mass spectrometry method for the analysis of various heavy metals in cannabis sativa plant material.

The Big Four Heavy Metals in Cannabis: Sample Preparation and Analysis via ICP-MS

In this interview, Jeffrey Williams the CEO of Exum Instruments discusses the details of how laser ablation laser ionization-time of flight-mass spectrometer (LALI-TOF-MS) is set to solve some of the many of the issues involved in sample preparation for the cannabis industry.

Sample Prep for Cannabis Made Easier

Here a scientifically based representative sampling plan for hemp grows is presented, detailing how to collect composite samples, how many to collect, and how to analyze them.

A Proposed Representative Sampling Plan for Hemp Grows

Laboratories are challenged with highly regulated and difficult sample schematics, sample preparation, extraction, and testing procedures that try to ensure accuracy and precision of testing. Accuracy in analytical testing starts at the very beginning with sampling and sample preparation prior to testing.