Tag: Marijuana

Marijuana Detector


Forensic Chemist Detects Marijuana-Use Based on Sweat Test

Photo by Maurício Eugênio on Pexels.com

Forensic chemist Jan Halámek is proving that our own perspiration not only gives away how drunk we are – but if we are high, too.

Through new research, published in December’s edition of ACS Sensors, the Halámek lab has captured the ability to detect a person’s marijuana-use based on contents in a small skin secretion that can be taken from fingerprints or any other sweat glands.


This discovery builds on the lab’s concept for a roadside testing kit to be used by law enforcement. In November, Halámek introduced a prototype for a color-changing test strip that detects blood alcohol content (BAC) based on ethanol levels in sweat.

“Currently there is a zero-tolerance policy when it comes to marijuana use and operating machinery,” said Halámek, an assistant professor of chemistry at the University at Albany. “While many states are moving to various stages of legalization, the focus is mostly on possession and in-home use. There are no reliable roadside devices being used to test for marijuana-impaired driving.”

“What makes the use of sweat as a biometric unique is that it is non-invasive. No blood needs to be drawn for a sample,” Halámek added. “Our test can be done instantaneously, on the side of the road, which eliminates any possibility of tampering.”

How It Works


Similar to the alcohol test strip, Halámek’s analysis to detect marijuana relies on a color change. However, instead of ethanol levels in the sweat sample, this test reacts to tetrahydrocannabinol (THC). THC is the main psychoactive component found in marijuana plants and its extracted forms including liquids (THC oils) and edibles (brownies, cookies, gummies, etc.) 


The analysis works by using an antibody that quantifies the THC metabolite.  When less of a color change is observed, this means a higher amount of THC metabolite is present in the sweat sample.

To put their discovery to the test, Halámek, along with his team of UAlbany graduate students, surveyed eight volunteers on their recent marijuana use. Four were users; four were non-users. The group then provided their fingerprints on a plastic wrap that was cut out and subject to analysis.

Results showed a clear difference in observed color change between the two groups.


“While drugs are a new topic for the Halámek lab, it is something we plan to continue diving into,” Halámek said. “Much of the fundamentals are the same as our previous research in terms of the collection, extraction, and use of sweat as a biometric.”

The Halámek Lab


Along with its roadside testing kit research, the Halámek lab has published a number of other groundbreaking forensics discoveries. In 2017, his team released a concept paper for a sweat-based authentication to unlock mobile and wearable devices. The lab has also released numerous studies on the use of physical crime scene evidence, such as fingerprints or blood residue, to quickly identify key characteristics of culprits.


Halámek joined UAlbany in 2013 and has been funded through numerous fellowships and a three-year grant from the Department of Justice and National Institute of Justice to develop non-invasive sensing concepts.

You can learn more about Halámek by visiting his research website and expert page.

Marijuana Use in E-Cigarettes Increases Among Youth

Photo by Kimzy Nanney

A study published today online in the Journal of the American Medical Association (JAMA) found marijuana use in electronic cigarettes has been increasing among U.S. middle and high school students from 2017 to 2018.

In the observational study, Hongying “Daisy” Dai, Ph.D., associate professor, University of Nebraska Medical Center College of Public Health used the National Youth Tobacco Survey to analyze responses from 38,000 students, grades 6-12. Dr. Dai, who has been studying e-cigarette use for five years, said e-cigarettes recently have increased very quickly among adolescents.

Among all students, the proportion who reported ever using marijuana in an e-cigarette increased from 11.1% in 2017 to 14.7% in 2018. The increases were seen among some demographic groups, including adolescents age 13 to 17 and Caucasian and Hispanic students.


“These statistics are very concerning as marijuana use in adolescence could lead to adverse effects in brain development, mental health and academic performance,” said Dr. Dai, a biostatistician. “Our other concern is e-cigarette use has also been related to severe respiratory diseases.

As of Nov. 20, Dr. Dai noted there had been 2,290 vaping-related lung injury cases and 47 deaths. About 77% of the cases were in people with a history of vaping products containing THC, the mind-altering ingredient found in the cannabis plant.

In 2018, the number of students using marijuana in e-cigarettes included:

  • 42.7% of students who ever used e-cigarettes;
  • 53.5% of current e-cigarette users; and
  • 71.6% of multiple tobacco product users. 

Dr. Dai said the increase in marijuana use in e-cigarettes could be attributable to:

  • the increase of “pod mod” e-cigarette products – small, easy-to-conceal devices that aerosolize liquid solutions containing nicotine, flavoring and other contents;
  • access to marijuana through informal sources such as friends, family members and illicit dealers; and
  • reduced perception among adolescents of the harms of marijuana use.

“Parents really need to raise their awareness about vaping. E-cigarette products look much like school supplies, so it’s hard for parents to know if their child is using e-cigarettes,” she said. “Even for me, it’s hard to distinguish between school supplies and e-cigarette products.”


She said a limitation of the study is that the information was self-reported. She added that studies about the short- and long-term health effects of using marijuana in e-cigarettes need to be done.

The study was supported by the National Cancer Institute and U.S. Food and Drug Administration Center for Tobacco Products.

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