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The effect of tea catechins on the forensic identification of urine: Urine camouflage to evade drug tests
Fumi Momota1, Takehiko Nakazono2, Brian Waters3
1Forensic Science Laboratory, Fukuoka Prefectural Police Headquarters, Japan; Department of Forensic Medicine, Faculty of Medicine, Fukuoka University, Japan.
Background:
We encountered a urine sample suspected of being mixed with tea, submitted by a suspect attempting to camouflage illegal drugs. Although urine should turn reddish-pink during a urea test with p-Dimethylaminocinnamaldehyde (DAC), this suspect's sample exhibited a blue coloration when tested with DAC.
Aim:
Our aim was to examine the influence and mechanism of green tea on various urine identification tests.
Results:
Our examination revealed that DAC forms a compound with the urea in urine, resulting in a reddish pink coloration with a molecular weight of 217. However, it has been reported that DAC binds to polyphenols such as catechin. In the case of catechin, DAC binds to the C8 position, forming a compound that exhibits the highest absorption at 640 nm and appears blue. we investigated the effect of urine from volunteers who had consumed a large amount of catechin on the urea test with DAC. Additionally, we carried out quantitative analysis of catechin in urine by LC-MS/MS after enzymatic treatment with β-glucuronidase. The concentration of urinary excreted catechin reached its peak approximately 3 to 4 h after ingestion. During the DAC test, urine samples collected 3 to 4 h after catechin ingestion displayed a bluish pink color, but not the blue color observed in the original suspect sample.
Conclusion:
This study investigated the impact of catechin on urine tests, revealing that a blue color in the DAC test indicates a high likelihood of camouflage by the suspect.
