Electrochemical Detection of Morphine in Untreated Human Capillary Whole Blood

Abstract

Disposable single-use electrochemical sensor strips were used for quantitative detection of small concentrations of morphine in untreated capillary whole blood. Single-walled carbon nanotube (SWCNT) networks were fabricated on a polymer substrate to produce flexible, reproducible sensor strips with integrated reference and counter electrodes, compatible with industrial-scale processes. A thin Nafion coating was used on top of the sensors to enable direct electrochemical detection in whole blood. These sensors were shown to detect clinically relevant concentrations of morphine both in buffer and in whole blood samples. Small 38 μL finger-prick blood samples were spiked with 2 μL of morphine solution of several concentrations and measured without precipitation of proteins or any other further pretreatment. A linear range of 0.5–10 μM was achieved in both matrices and a detection limit of 0.48 μM in buffer. In addition, to demonstrate the applicability of the sensor in a point-of-care device, single-determination measurements were done with capillary samples from three subjects. An average recovery of 60% was found, suggesting that the sensor only measures the free, unbound fraction of the drug. An interference study with other opioids and possible interferents showed the selectivity of the sensor. This study clearly indicates that these Nafion/SWCNT sensor strips show great promise as a point-of-care rapid test for morphine in blood.

Design of Electrochemically Reduced Graphene Oxide/Titanium Disulfide Nanocomposite Sensor for Selective Determination of Ascorbic Acid

“…Notably, tiny amperage responses of Cys (7.5%) and DA (8.9%) are observed as compared to AA, indicating its negligible interference effect. Since the maximum tolerance level of the interferents is taken to be 100-fold higher than AA, it can give rise to an approximately ±10% relative error and thus not have any influence during the determination of AA . The appearance of a small peak followed by the steady response of Cys can be a result of diffusion in the electrochemical system .…”

“…Since the maximum tolerance level of the interferents is taken to be 100-fold higher than AA, it can give rise to an approximately ±10% relative error and thus not have any influence during the determination of AA. 65 The appearance of a small peak followed by the steady response of Cys can be a result of diffusion in the electrochemical system. 66 Previously, Wu et al 67 reported that generation of the tiny response of Cys can be attributed to the surface complexes formed between the active oxygencontaining groups of erGO, especially the aldehyde groups and the N-terminal Cys.…”

Introduction of an electrochemical point‐of‐care assay for quantitative determination of paracetamol in finger‐prick capillary whole blood samples

“…5 Moreover, electrochemical test strips enable analysis of small complex biological samples, such as whole blood, with minimal 6 or no sample treatment. 7 Recently, we described the production of single-walled carbon nanotube/Nafion-based test strips (SWCNT/Nafion) with industrial high throughput methods.…”

“…Paracetamol can be readily detected with electrochemical methods 4 and it is well suited to point‐of‐care (POC) analysis, given the availability of inexpensive and easy‐to‐use portable potentiostats 5 . Moreover, electrochemical test strips enable analysis of small complex biological samples, such as whole blood, with minimal 6 or no sample treatment 7 . Recently, we described the production of single‐walled carbon nanotube/Nafion‐based test strips (SWCNT/Nafion) with industrial high throughput methods.…”

Voltammetric Determination of 3-Methylmorphine Using Glassy Carbon Electrode Modified with rGO and Bismuth Film

“…Over the past few decades, researchers from different fields have shown an increasingly growing interest in the determination of drugs present in clinical, environmental and pharmaceutical samples with a view to tackling the problems related to drug intoxication and wastewater contamination as well as ensuring the quality control of pharmaceutical products [ 1 ]. This has resulted in the development of several techniques with accurate tools targeted at the qualitative (simple yes/no analysis) and/or quantitative determination of drugs at trace levels in different samples (including urine, serum and water).…”