A versatile SERS platform based on conductive MOF-enforced carbon paper for rapidly and sensitively monitoring diazepam in aquatic products

Herein, a versatile surface enhanced Raman scattering (SERS) platform was firstly constructed by integrating conductive metal organic framework (CMOF) with controlled electrodeposition of Au nanoparticles (Au NPs) on flexible carbon paper (CP-CMOF@Au) for sensitively recognizing diazepam (DZP) in aquatic products. The CMOF not only provided a pre-concentration effect for boosting sensitivity, but also dramatically improved the intrinsic electrical conductivity contributing to homogeneous distribution of Au NPs and forming SERS-active "hot spot" with superior stability and reproducibility. Based on CP-CMOF@Au chip, DZP can be sensitively detected with low limit of detection of 0.64 ng mL-1 and wide linear detection range from 0.001 to 10 μg mL-1. Also, DZP in aquatic products can be collected and recognized using multiple approaches (drip coating, soaking and wiping) with excellent reusability and satisfactory recovery of 85.8-103.3%. This method would provide an ingenious SERS strategy for rapidly monitoring DZP in aquatic products with good practical applicability.

Rapid determination of eight benzodiazepines in suspected counterfeit pharmaceuticals using surface-enhanced Raman scattering with handheld Raman spectrometers

The excessive prescription of benzodiazepines is putting more people at risk of dependence on these drugs and is exacerbating the fatal overdose toll of opioids. A rapid and sensitive SERS method has been developed for trace detection of select benzodiazepines in low-dosage suspect counterfeit tablets, capsules, and injectable solutions using two different portable handheld Raman spectrometers equipped with either a 785-nm laser or a 1064-nm laser. A total of 169 samples and blanks were examined using five handheld Raman spectrometers, which provided data set of 729 examinations. The extraction/SERS procedures yielded true positive rates above 90% for alprazolam, diazepam, and midazolam using the 1064-nm device and yielded true positive rates above 95% for alprazolam, clonazepam, diazepam, estazolam, midazolam, and temazepam using the 785-nm device; however, the extraction/SERS procedures yielded true positive rates below 60% for lorazepam and triazolam. The minimum concentration (C_min ) of the benzodiazepine standards that reproducibly yielded a positive match ranged from 1 to 10 μg/ml using the 1064-nm laser device and from 0.5 to 50 μg/ml using the 785-nm laser device. For the analysis of authentic and suspect counterfeit tablets containing these benzodiazepines, the measured C_min ranged between 10 and 15 µg per tablet or capsule for 1064-nm laser device and 1-100 µg per tablet or capsule for 785-nm laser device. The developed methods are simple, rapid, and ideal for screening suspect benzodiazepine-containing pharmaceutical products at satellite laboratories located within or near international mail facilities and express courier hubs.

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.