An electrochemical aptasensor for methylamphetamine rapid detection by single-on mode based on competition with complementary DNA.

A simple and rapid electrochemical sensing method with high sensitivity and specificity of aptamers was developed for the detection of methylamphetamine (MAMP). A short anti-MAMP thiolated aptamer (Apt) with a methylene blue (MB) probe at 3'-end was immobilized on the surface of a gold electrode (MB-Apt-S/GE). The electrochemical signal appeared when MAMP presenting in the sample solution competed with cDNA for binding with MB-Apt-S. Under optimized conditions, the liner range of this signal-on electrochemical aptasensor for the detection of MAMP achieved from 1.0 to 10.0 nmol/L and 10.0-400 nmol/L. LOD 0.88 nmol/L were obtained. Satisfactory spiked recoveries of saliva and urine were also obtained. In this method, only 5 min were needed to incubate before the square wave voltammetry (SWV) analysis, which was much more rapid than other electrochemical sensors, leading to a bright and broad prospect for the detection of MAMP in biological sample. This method can be used for on-site rapid detection on special occasions, such as drug driving scenes, entertainment venues suspected of drug use, etc.

Recovery incentives program: California's contingency management benefit.

OBJECTIVE: The role of methamphetamine and cocaine use in California's drug poisoning (overdose) crisis has dramatically increased in the past five (5) years and has disproportionately affected American Indian, Alaska Native, and Black Californians. No FDA-approved medications currently exist for the treatment of individuals with stimulant use disorder (StimUD). Outside the Veteran's Administration, the Recovery Incentives Program: California's Contingency Management Benefit is the first large scale implementation of contingency management (CM). CM is the behavioral treatment with the most evidence and largest effect sizes for StimUD. METHODS: The Program uses a CM protocol where participants can receive a maximum of $599 over a six-month period, contingent upon 36 stimulant-negative urine test results. Urine tests are conducted using a set of approved, CLIA-waived, point-of-care urine drug tests (UDTs). To ensure fidelity to the CM protocol and to prevent fraud, waste, and abuse, all aspects of incentive accounting and distribution are managed electronically via a custom-developed software system. Incentive distribution utilizes electronic gift cards. A significant innovation of the project is the conceptualization of the CM Coordinator, a designated and highly trained and supervised individual responsible for all aspects of CM operation in a specific site. RESULTS AND CONCLUSIONS: The California Department of Health Care Services contracted with UCLA to develop and implement a robust evaluation of the Program; goals include evaluating the effectiveness of real-world implementation and facilitating quality improvement. The project will likely significantly impact the use of CM for StimUD nationally and may well reduce stimulant-related drug poisoning deaths.

Analysis of Methamphetamine in Urine by HPLC with Solid-Phase Dispersive Extraction and Solid-Phase Fluorescence Derivatization.

We have developed a fluorescence detection-liquid chromatography (HPLC-FL) method that involves sample pretreatment by solid-phase dispersive extraction (SPDE) and solid-phase fluorescence derivatization for the simple and rapid analysis of methamphetamine (MA) in urine. This method uses a reversed-phase polymeric solid-phase gel to clean up analytes in SPDE, followed by fluorescence derivatization with 9-fluorenylmethyl chloroformate (FMOC) in the solid-phase. The optimal conditions for SPDE and solid-phase fluorescence derivatization were obtained when J-SPEC PEP was used as the solid-phase gel and 0.5 mmol/L FMOC in 50 mmol/L borate buffer solution (pH 10) was used as the fluorescence derivatization reagent. The recovery experiment of MA in urine yielded a clean chromatogram with no interfering peaks, demonstrating the validity of our method; the recoveries were 83.6% when spiked at a low concentration level (100 ng/mL) and 80.7% when spiked at a high concentration level (1000 ng/mL). Compared with the conventional liquid-phase method, the reaction product (FMOC-MA) of solid-phase fluorescence derivatization had higher stability. Reaction rate constants were calculated by changing the temperature conditions, and physicochemical parameters, including activation energy and activation entropy involved in the degradation reaction, were obtained from the Arrhenius plot and analyzed thermodynamically. Taken together, our results suggest that the HPLC-FL method with SPDE and solid-phase fluorescence derivatization for sample pretreatment provides a simple and rapid means of analyzing MA in urine samples.

Combination of quadrupole isotope dilution mass spectrometry with simultaneous derivatization and spray assisted droplet formation-liquid phase microextraction for the determination of methamphetamine in human urine and serum samples by gas chromatography mass spectrometry.

In this study, an analytical method with high accuracy and precision was developed for the determination of methamphetamine in human urine and serum samples by gas chromatography-mass spectrometry (GC-MS). A simultaneous derivatization and spray assisted droplet formation-liquid phase microextraction (SADF-LPME) method was proposed to derivatize and preconcentrate target analyte. Quadruple isotope dilution (ID4) was used to provide high accuracy and precision for methamphetamine determination in the samples. After the optimization studies for the derivatization and microextraction parameters, limit of detection (LOD) and limit of quantitation (LOQ) for the developed SADF-LPME method were found to be 48.0 and 159.9 µg/kg, respectively. Recovery studies were implemented to verify the applicability and accuracy of the developed method for human urine and serum samples. The SADF-LPME method gave low percent recovery results (30.5-61.0%) for the spiked urine and serum samples showing that it failed to minimize or eliminate matrix effects for the analyte. Hence, methamphetamine acetamide-d3 was synthesized and purified in our research laboratory to be used as methamphetamine isotopic analogue in the ID4 method. When the SADF-LPME method was combined with ID4, the percent recovery values for urine and serum samples were calculated as 99.7-100.0% and 99.4-100.2%, respectively. These results demonstrated the applicability and accuracy of the proposed method for urine and serum samples.

Update: Correlation of Fentanyl Positive Drug Screens with other Medications in Patients from Pain, Rehabilitation and Behavioral Programs.

OBJECTIVE: To monitor fentanyl polydrug use over past six years. METHOD: Calculate percent of fentanyl and other drugs positive in urine drug tests. RESULTS: Percent of fentanyl positive drug tests remained unchanged, but increases in fentanyl/methamphetamine and fentanyl/marijuana were observed. CONCLUSIONS: Fentanyl laced illicit drugs remain a major substance abuse problem.

Derivatization-assisted immunoassays: application for group-specific detection of potent methamphetamine and amphetamine enantiomers.

Reliable and feasible tools for detecting (S)-methamphetamine [(S)-MAP] and (S)-amphetamine [(S)-AP] are required for regulating their illicit circulation. Antibodies that react equally to these stimulants are desirable for this purpose, but have been difficult to generate because of the crucial difference between their characteristic structures: i.e., N-methylamino (MAP) and amino (AP) groups. Furthermore, their small molecular masses (Mr < 150) have hampered the generation of high-affinity antibodies. To overcome these problems, we converted (S)-MAP and -AP into their 2-(trimethylsilyl)ethyl carbamate forms, Teoc-(S)-MAP and -AP, respectively, as surrogate analytes. The Teoc-derivatization not only increases their molecular masses, but also masks their structural differences. We generated a novel monoclonal antibody that showed a satisfactory affinity to Teoc-(S)-MAP residues (Kd = 13 nM as the IgG form) and developed a competitive enzyme-linked immunosorbent assay (ELISA) using microplates containing immobilized Teoc-(S)-MAP residues. Almost overlapping dose-response curves were obtained for Teoc-(S)-MAP and -AP, with the limit of detection of 0.078 and 0.10 ng per assay, respectively. A fixed amount of test powder sample (1 mg) was derivatized with Teoc-O-succinimidyl for 5 min, and subjected to ELISA using Teoc-(S)-MAP as the calibration standard. Under this protocol, (S)-MAP and -AP were converted to their Teoc derivatives with 30% and 34% yield, respectively, determined using ELISA as "Teoc-(S)-MAP equivalent," being distinguished from the derivatization products of (R)-MAP, (R)-AP, ephedrine, (S)-methylenedioxymethamphetamine, tyramine, dopamine, and ß-alanine. This ELISA detected as little as 10 µg of (S)-MAP and -AP, and (S)-MAP in urine obtained from (S)-MAP-administered rats. Immunochromatography devices were also developed using gold nanoparticles coated with the monoclonal antibody, with which 0.10 mg of (S)-MAP and -AP was detected by the naked eye. We conclude that the present derivatization-assisted immunoassays may be useful for the detection of (S)-MAP and/or -AP in early stage screening of suspicious substances.

Transmission Of Tuberculosis Among illicit drug use Linkages (TOTAL): A cross-sectional observational study protocol using respondent driven sampling.

People who use illicit drugs (PWUDs) have been identified as a key at-risk group for tuberculosis (TB). Examination of illicit drug use networks has potential to assess the risk of TB exposure and disease progression. Research also is needed to assess mechanisms for accelerated TB transmission in this population. This study aims to 1) assess the rate of TB exposure, risk of disease progression, and disease burden among PWUD; 2) estimate the proportion of active TB cases resulting from recent transmission within this network; and 3) evaluate whether PWUD with TB disease have physiologic characteristics associated with more efficient TB transmission. Our cross-sectional, observational study aims to assess TB transmission through illicit drug use networks, focusing on methamphetamine and Mandrax (methaqualone) use, in a high TB burden setting and identify mechanisms underlying accelerated transmission. We will recruit and enroll 750 PWUD (living with and without HIV) through respondent driven sampling in Worcester, South Africa. Drug use will be measured through self-report and biological measures, with sputum specimens collected to identify TB disease by Xpert Ultra (Cepheid) and mycobacterial culture. We will co-enroll those with microbiologic evidence of TB disease in Aim 2 for molecular and social network study. Whole genome sequencing of Mycobacteria tuberculosis (Mtb) specimens and social contact surveys will be done for those diagnosed with TB. For Aim 3, aerosolized Mtb will be compared in individuals with newly diagnosed TB who do and do not smoke illicit drug. Knowledge from this study will provide the basis for a strategy to interrupt TB transmission in PWUD and provide insight into how this fuels overall community transmission. Results have potential for informing interventions to reduce TB spread applicable to high TB and HIV burden settings. Trial registration: Clinicaltrials.gov Registration Number: NCT041515602. Date of Registration: 5 November 2019.

Fluorescence resonance energy transfer-thermal lens spectrometry (FRET-TLS) as molecular counting of methamphetamine.

A novel and sensitive approach has been presented for the determination of methamphetamine (METH) based on fluorescence resonance energy transfer-thermal lens spectrometry (FRET-TLS). Due to the affinity of fluorescein molecules to the surface of AuNPs through the electrostatic interaction and thereby caused reduction of the distance between fluorescein and AuNPs, the best way for de-excitation of excited fluorescein is FRET. The energy absorbed by fluorescein transferred to AuNPs causes enhancement of the thermal lens effect. The thermal lens of the fluorescence molecule could be enhanced through a proper acceptor. Upon the addition of methamphetamine, the fluorescein molecules are detached from the surface of AuNPs, due to the stronger adsorption of methamphetamine. As a result, the fluorescence of fluorescein recovered, and the thermal lens effect of fluorescein decreased. The mechanism of energy transfer was evaluated by two different methods including time-resolved spectroscopy and thermal lens spectrometry. Under the optimal conditions, the thermal lens signal was linearly proportional to methamphetamine concentration in the range 5 - 80 nM. The limit of detection and limit of quantitation were 1.5 nM and 4.5 nM, respectively. The detection volume and limit of molecules in the detection volume were 960 attoliter and 87 molecules, respectively. The method was successfully applied for the determination of methamphetamine in human blood plasma and urine.

Bupropion and Naltrexone in Methamphetamine Use Disorder.

BACKGROUND: The use of naltrexone plus bupropion to treat methamphetamine use disorder has not been well studied. METHODS: We conducted this multisite, double-blind, two-stage, placebo-controlled trial with the use of a sequential parallel comparison design to evaluate the efficacy and safety of extended-release injectable naltrexone (380 mg every 3 weeks) plus oral extended-release bupropion (450 mg per day) in adults with moderate or severe methamphetamine use disorder. In the first stage of the trial, participants were randomly assigned in a 0.26:0.74 ratio to receive naltrexone-bupropion or matching injectable and oral placebo for 6 weeks. Those in the placebo group who did not have a response in stage 1 underwent rerandomization in stage 2 and were assigned in a 1:1 ratio to receive naltrexone-bupropion or placebo for an additional 6 weeks. Urine samples were obtained from participants twice weekly. The primary outcome was a response, defined as at least three methamphetamine-negative urine samples out of four samples obtained at the end of stage 1 or stage 2, and the weighted average of the responses in the two stages is reported. The treatment effect was defined as the between-group difference in the overall weighted responses. RESULTS: A total of 403 participants were enrolled in stage 1, and 225 in stage 2. In the first stage, 18 of 109 participants (16.5%) in the naltrexone-bupropion group and 10 of 294 (3.4%) in the placebo group had a response. In the second stage, 13 of 114 (11.4%) in the naltrexone-bupropion group and 2 of 111 (1.8%) in the placebo group had a response. The weighted average response across the two stages was 13.6% with naltrexone-bupropion and 2.5% with placebo, for an overall treatment effect of 11.1 percentage points (Wald z-test statistic, 4.53; P<0.001). Adverse events with naltrexone-bupropion included gastrointestinal disorders, tremor, malaise, hyperhidrosis, and anorexia. Serious adverse events occurred in 8 of 223 participants (3.6%) who received naltrexone-bupropion during the trial. CONCLUSIONS: Among adults with methamphetamine use disorder, the response over a period of 12 weeks among participants who received extended-release injectable naltrexone plus oral extended-release bupropion was low but was higher than that among participants who received placebo. (Funded by the National Institute on Drug Abuse and others; ADAPT-2 ClinicalTrials.gov number, NCT03078075.).

Methamphetamine-associated pulseless electrical activity in a young child.

This is a case report of a 19-month-old female who presented to the emergency department in cardiac arrest after methamphetamine exposure. Prior to presentation, she had seizure-like activity and then became unresponsive. On arrival, she had dilated pupils, intermittent clonus, and pulseless electrical activity. She was found to have full thickness circumferential burns of her bilateral lower extremities. She received 12 doses of epinephrine, cardiopulmonary resuscitation, and volume resuscitation after which she had return of spontaneous circulation and was transferred to the intensive care unit on an epinephrine drip. Initial laboratory studies showed a mixed metabolic and respiratory acidosis and hyperglycemia. An initial urine immunoassay for drugs of abuse was negative, however, 5 h later, a second urine immunoassay was positive for amphetamine. The first specimen was also sent for liquid chromatography-mass spectrometry analysis that later returned positive for methamphetamine and amphetamine. In retrospect, the initial urine screen was found to have evidence of amphetamine below the threshold for positivity (500 ng/mL), and the second urine specimen was highly positive, with an amphetamine level of >1450 ng/mL. In this case, what turned out to be a sub-threshold rather than undetectable level was clinically significant, highlighting the challenges of urine screening in cases of suspected poisoning syndromes with atypical presentations. Our case also suggests the possibility of PEA as a presentation of methamphetamine toxicity in a child.

Urinary excretion profile of methiopropamine in mice following intraperitoneal administration: A liquid chromatography-tandem mass spectrometry investigation.

We have considered the urinary excretion profile of methiopropamine (MPA), a thiophene ring-based structural analog of methamphetamine with similar stimulant effects, with the aim of selecting the most appropriate marker(s) of intake that may be useful in forensic analysis. For this purpose, in vitro studies were preliminarily performed on human liver microsomes for tracing the phase I metabolic pathways of MPA, preselecting the best candidates as potential target analytes, and designing the optimal experimental strategy. In vivo studies were then conducted on mice, after the intraperitoneal administration of a 10-mg/kg dose. Urine samples were collected every 3 h in the first 9 h and, subsequently, from 24 to 36 h, and stored at -80°C until further analysis. The measurements were performed using a targeted procedure based on liquid/liquid extraction followed by liquid chromatography-tandem mass spectrometry analysis. Our results show that in the time interval 0-9 h after administration, MPA was extensively oxidized mainly to nor-MPA, oxo-MPA, and two hydroxylated metabolites (ie, hydroxy-aryl-methiopropamine and hydroxy-alkyl-methiopropamine). All phase I metabolites underwent phase II metabolism, with the formation of nor-hydroxy-methiopropamine only in phase II, confirmed by the results obtained after enzymatic hydrolysis with ß-glucuronidase and arylsulfatase. In the time interval 24-36 h after administration, only unchanged MPA and nor-MPA were detected, suggesting that these two markers are those endowed with the highest diagnostic value. The method was validated for these two principal markers, proving to be fit for anti-doping, toxicological, and forensic analyses.

In situ electrosynthesis of a copper-based metal-organic framework as nanosorbent for headspace solid-phase microextraction of methamphetamine in urine with GC-FID analysis.

For the first time, a fiber coating based on copper metal-organic framework was fabricated on an anodized stainless steel wire by an in situ electrosynthesis approach. The fiber was used for the preconcentration and determination of methamphetamine by headspace solid-phase microextraction followed by gas chromatography-flame ionization detection. The electrosynthesis of the fiber coating was performed under a constant potential of - 1.7 V by controlling the electrogeneration of OH- in a solution containing sodium nitrate as the probase, 1,2,4,5-benzenetetracarboxylate acid as the ligand and copper nitrate as the cation source. The coating was characterized using field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The effective parameters on the electrosynthesis, extraction, and desorption processes were thoroughly optimized. Under the optimized conditions, metamphetamine (MAP) was quantified over a linear range of 0.90-1000.0 ng mL-1 with R2 > 0.997. A limit of detection of 0.1 ng mL-1 was achieved, and intra- and inter-day relative standard deviations were found within the range 3.0-4.4% and 2.8-3.9%, respectively. Finally, the method was successfully applied to determination of MAP in urine samples with good recoveries in the range 85.0-102.5%. Graphical abstract Schematic representation of the in-situ electrochemical synthesis of a Cu-based metal-organic framework and its application in a headspace SPME procedure for the measuring methamphetamine in urine samples followed by GC-MS analysis.

On-Site and Quantitative Detection of Trace Methamphetamine in Urine/Serum Samples with a Surface-Enhanced Raman Scattering-Active Microcavity and Rapid Pretreatment Device.

Here, it reports a high-throughput detection method for reliably quantitative analysis of illegal drugs in complex biological samples by means of a surface-enhanced Raman scattering (SERS) active microcavity and rapid pretreatment device. Based on the well-made hemispherical microcavities that regularly distributed on a glass array, the quality-controllable microcavity device is fabricated by the compact self-assembly of core-shell nanopeanuts (CSNPs) onto the inside surface. Both the CSNPs with a quantifiable internal standard signal of crystal violet acetate anchored inside their gap and the well-made microcavity referred to the physical amplification of the microscale groove surface will do well in trace analysis, which will allow us to realize the accurately quantitative SERS analysis of targeted analytes spread on the bottom area of the microcavity array. As an example, 0.8 nM malachite green and 160 ppb methamphetamine (MATM) have been successively detected in a wide range as standard, while even 0.01 ppm MATM mixed in the urine/serum samples has been efficiently tested by the microcavity device equipped with a rapid pretreatment device (manual monolithic column syringe needle). All of the above suggest that the SERS-active microcavity equipped with a rapid pretreatment device has potential in the on-site quick test of trace amounts of illegal drugs in bodily fluid samples or other field analysis of food sanitation, environmental safety, and public health.

Use of Amphetamine-Type Stimulants Among Emergency Department Patients With Untreated Opioid Use Disorder.

STUDY OBJECTIVE: Concurrent use of amphetamine-type stimulants among individuals with opioid use disorder can exacerbate social and medical harms, including overdose risk. The study evaluated rates of amphetamine-type stimulant use among patients with untreated opioid use disorder presenting at emergency departments in Baltimore, MD; New York, NY; Cincinnati, OH; and Seattle, WA. METHODS: Emergency department (ED) patients with untreated opioid use disorder (N=396) and enrolled between February 2017 and January 2019 in a multisite hybrid type III implementation science study were evaluated for concurrent amphetamine-type stimulant use. Individuals with urine tests positive for methamphetamine, amphetamine, or both were compared with amphetamine-type stimulant-negative patients. RESULTS: Overall, 38% of patients (150/396) were amphetamine-type stimulant positive; none reported receiving prescribed amphetamine or methamphetamine medications. Amphetamine-type stimulant-positive versus -negative patients were younger: mean age was 36 years (SD 10 years) versus 40 years (SD 12 years), 69% (104/150) versus 46% (114/246) were white, 65% (98/150) versus 54% (132/246) were unemployed, 67% (101/150) versus 49 (121/246) had unstable housing, 47% (71/150) versus 25% (61/245) reported an incarceration during 1 year before study admission, 60% (77/128) versus 45% (87/195) were hepatitis C positive, 79% (118/150) versus 47% (115/245) reported drug injection during 1 month before the study admission, and 42% (62/149) versus 29% (70/244) presented to the ED for an injury. Lower proportions of amphetamine-type stimulant-positive patients had cocaine-positive urine test results (33% [50/150] versus 52% [129/246]) and reported seeking treatment for substance use problems as a reason for their ED visit (10% [14/148] versus 19% [46/246]). All comparisons were statistically significant at P<.05 with the false discovery rate correction. CONCLUSION: Amphetamine-type stimulant use among ED patients with untreated opioid use disorder was associated with distinct sociodemographic, social, and health factors. Improved ED-based screening, intervention, and referral protocols for patients with opioid use disorder and amphetamine-type stimulant use are needed.

Intoxicaciones por anfetamina y metanfetamina atendidas en los servicios de urgencias: características clínicas y utilidad de la confirmación analítica / Amphetamine and methamphetamine poisonings attended by emergency services: clinical characteristics and the usefulness of laboratory confirmation

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Methamphetamine intoxication and acute kidney injury: A prospective observational case series.

AIM: The effects of methamphetamine intoxication on the kidney are not well reported. We aimed to investigate acute kidney injury (AKI) associated with methamphetamine intoxication, in particular its severity, duration and association with rhabdomyolysis. METHODS: This is a prospective observational series of methamphetamine-intoxicated patients presenting to an Emergency Department. Patients self-reporting recent methamphetamine use, with a positive urine drug screen and an elevated creatinine, were eligible for the study. Urinary neutrophil gelatinase-associated lipocalin (NGAL) was measured, and serum creatinine, creatine kinase and cystatin C concentrations were performed on arrival and at several time points until discharge from hospital. Demographic and clinical data were obtained from the medical records. RESULTS: There were 634 presentations with methamphetamine intoxication over a 10-month period, with 73/595(12%) cases having an elevated serum creatinine concentration on arrival. Fifty presentations in 48 patients were included in the study. Most patients (85%) were male with a median age of 32 years. The median serum creatinine concentration on presentation was 125 µmol/L (IQR:113-135 µmol/L) with 45 (90%) presentations meeting diagnostic criteria for AKI. Concurrent rhabdomyolysis occurred in 22 (44%) presentations with a median CK of 2695 U/L (IQR:1598-5060 U/L). Cystatin C was elevated (> 0.98 mg/L) in 18 cases. An elevated NGAL concentration (>150 µg/L) was present in five (10%) cases. No patients required dialysis. The median length of stay was 19 hours (IQR 14-24 hours). CONCLUSION: AKI is common in methamphetamine intoxication. The kidney injury is relatively mild and short-lived, resolving with crystalloid therapy.

Optoplasmonic Hybrid Materials for Trace Detection of Methamphetamine in Biological Fluids through SERS.

Optoplasmonic materials comprising both photonic and plasmonic elements are of particular interest for the development of substrates for surface-enhanced Raman spectroscopy (SERS). In this work, a layer of analyte-carrying dielectric nano/microspheres is placed on top of a monolayer of gold nanoparticles to enhance the intensity of the electric (E-) field localization and to enrich the analyte close to the electromagnetic hot spots. Numerical simulations of the hybrid structure confirm an increased and spatially expanded E-field enhancement at the interface. Due to a decreasing filling fraction with increasing size of the dielectric spheres, simulations predict a saturated SERS enhancement for dielectric microspheres with a diameter larger than 4 µm, which is confirmed by experimental SERS measurements. The dielectric microsphere can be functionalized with surface ligands that facilitate the binding of target molecules in solution. The deposition of the analyte-loaded microspheres on the self-assembled gold nanoparticle ensures a high local concentration of analytes in the electromagnetic "hot" surface. The performance of the optoplasmonic SERS approach for detecting methamphetamine in saliva and urine is tested, and the detection of analytes at nanomolar (nM) concentrations is demonstrated.

Sensitive imprinted optical sensor based on mesoporous structure and green nanoparticles for the detection of methamphetamine in plasma and urine.

Methamphetamine (MA), a psychoactive substance with many medicinal applications in different countries, has destructive impacts on the nervous system and brain and can lead to addiction. The optimal system for MA determination must be able to measure the tiny amount of MA in complex matrixes accurately. In the current work, a simple and biocompatible sensitive optical probe was developed based on molecularly imprinted polymers (MIPs) technique and by using green CQDs and mesoporous structured imprinting microspheres (SiO2@CQDs@ms-MIPs). CQDs (ФF = 33%) were synthesized via the hydrothermal method using natural chewing gum as carbon source. SiO2 nanoparticles were used as the backup substrate for the placement of CQDs. In spite of biocompatibility, porosity and having high specific area are the unique features of SiO2 nanoparticles. When MA is present, the fluorescence response of MIPs enhances. This is caused by the passivation and adjustment of active clusters that are present on the surface of CQDs. By this optical sensor, the favorable linear dynamic range (5.0-250 µM) and the detection limit (1.6 µM) were obtained. The applicability of the advanced sensor was studied in real samples such as human urine and human blood plasma. Acceptable results were obtained and recovery amounts were in the 92-110% interval.

LC-MS/MS method for the quantification of new psychoactive substances and evaluation of their urinary detection in humans for doping control analysis.

The constant legal adaptation of new psychoactive substances (NPS), challenges their evaluation in different fields. In sports, NPS are prohibited in competition with a reporting limit (RL) of 50 ng/mL for the parent compound or a metabolite. However, there is a lack of comprehensive methodologies and excretion studies for monitoring NPS. This work aims to develop an analytical methodology for the NPS quantification and to evaluate the suitability of monitoring the urinary parent stimulants after NPS misuse. A method for the quantification of 14 common NPS was developed and validated. The method was found to be linear in the range 1-1000 ng/mL, and was shown to be accurate and precise. A lowest limit of quantification (LLOQ) of 1 ng/mL was established for all analytes except for benzylpiperazine (5 ng/mL). The method was able to confirm the identity of the analytes at the LLOQ for most NPS. The methodology was applied to the quantification of the parent compound in urine samples collected from an observational study where several healthy volunteers (n ≥ 6 per drug) ingested active doses of mephedrone (MEPH), methylone (MDMC), 2,5-dimetoxy-4-ethylphenetylamine (2C-E), or 6-(2-aminopropyl)benzofuran (6-APB). It was observed that for MDMC and 6-APB, the quantification of the urinary parent drug at the current RL is a proper strategy for detecting their misuse. However, this strategy seems to be insufficient for evaluating MEPH and 2C-E misuse. Monitoring the most abundant metabolite of MEPH (4'-carboxy-MEPH) and the reduction of the RL to 10 ng/mL for the 2C-E evaluation are proposed.