High-performance liquid chromatographic determination of morphine in biological samples: an overview of separation methods and detection techniques

Boron-cluster-based porous BCN material modified electrode for electrochemical determination of morphine in serum

Porous highly boron-doped BCN (p-BCN) was produced by using a boron cluster salt (closo-[B₁₂H₁₂]^2-) as the boron-based precursor and SiO₂ as a hard template. The synthesized p-BCN was used in an electrochemical sensor for the ultrasensitive and highly selective detection of morphine (MOP). The optimal conditions for MOP detection were determined by optimizing the experimental conditions. Under these optimal conditions, the p-BCN-based sensor exhibited excellent MOP detection performance (working potential of 0.2 V). Specifically, it showed a detection range of 0.05 to 200 μM and a detection limit of 17.8 nM. Notably, the p-BCN-based electrochemical sensor was successfully applied to the determination of MOP in human blood, and the results showed satisfactory recovery and accuracy. Therefore, this sensor can be used as an effective platform for the detection of MOP in human blood samples.

Dual Naked-Eye and Optical Chemosensor for Morphine Detection in Biological Real Samples Based on Cr(III) Metal-Organic Framework Nanoparticles

The analytical detection and quantification of abuse drugs such as morphine (MOR) in biological samples are vital missions and remains to attract challenges for forensic toxicology, law enforcement, world antidoping organization, and social health fields. MOR, a benchmark analgesic drug known as "pain killer", is one of the powerful opioid medications for relieving pain, and overdose of MOR is toxic. In this article, novel promising chromium metal-organic framework nanoparticles [Cr(III)-MOF-NPs] were produced via facile synthesis and characterized using high-resolution transmission electron microscopy, field-emission scanning electron microscopy/energy-dispersive X-ray spectroscopy, mass spectrometry, X-ray photoelectron spectroscopy, elemental analysis, UV-vis, Fourier transform infrared, and thermogravimetry/differential scanning calorimetry, as well as photoluminescence (PL) investigation and magnetic properties. The PL study results revealed that the Cr(III)-MOF-NPs exhibited an emission band at 593 nm. The Cr(III)-MOF-NPs could be used in fast, selective, and sensitive MOR detection and quantification. Under the optimum experimental conditions, with the addition of MOR, a blueshift from 593 to 566 nm occurred with a remarkable PL intensity enhancement, and the color changed from brown to yellow (visually/naked-eye detection). The Cr(III)-MOF-NPs optical chemosensor exhibited a stable response for MOR in a concentration range between 0.1 and 350 nM. The detection and quantification limits were 0.167 and 0.443 nM, respectively, with a correlation coefficient (r 2) of 0.96. The developed PL chemosensor showed high selectivity for MOR over other competing interfering matrices. Moreover, the ultrasensitive chemosensor was extensively used for the determination of MOR spiked in different real samples (serum and urine samples) with acceptable recoveries and satisfactory results.

Determination of Morphine in Human Urine by the Novel Competitive Fluorescence Immunoassay

A competitive fluorescence immunoassay for the identification and quantification of morphine has been developed on the basis of hapten-coated plate format. Hapten was prepared through covalent conjugating a morphine derivative with albumin bovine. In the immunoassay, the hapten was inoculated on a 96-well plate and then bound with monoclonal antibodies labeled with a signal indicating dye, fluorescein isothiocyanate (FITC). Unbound FITC-antibodies were rinsed off from the plate. The fluorescein intensity decreases in the presence of morphine molecules due to the competitively binding to antibodies against hapten. The intensity is inversely correlated with the concentration of morphine. In quantitative analysis for urine samples, we obtained a linearity range of 0.2 μg/mL∼2.5 μg/mL, along with a detection limit of c.a. 1 ng/mL. The fluorescence immunoassay shows low cross-reactivity (below 10%) to 6-acetylmorphine, 3-acetylmorphine, and heroine. The developed method produced comparable results to the standard GC-MS/MS method. In conclusion, a rapid and efficient screening tool for morphine in clinical human urine has been established.

Bioorthogonal Reaction-Mediated ELISA Using Peroxide Test Strip as Signal Readout for Point-of-Care Testing

This work demonstrates a highly sensitive peroxide test strip (PTS)-based enzyme-linked immunosorbent assay (ELISA) for both qualitative and quantitative detection of drugs of abuse (morphine) and disease biomarkers (interleukin-6 and HIV-1 capsid antigen p24). This color-based PTS is a commercially available product with advantages of low cost, easy operation, and portability, and it is an ideal signal readout strategy in ELISA to simplify the immunoassay procedures and enable point-of-care testing (POCT). In addition, we introduce the bioorthogonal reaction that can effectively amplify the signal by controlling the cycles of bioorthogonal reaction to achieve the desirable sensitivity depending on different analytes. The limit of detection is 0.2 ng/mL for morphine, 3.98 pg/mL for interleukin-6, and 11.6 pg/mL for detection of HIV-capsid antigen (p24). This PTS-ELISA applies to both the qualitative and quantitative detection of IL-6 and p24 in clinical serum samples with good accuracy, which provides a promising tool for the POCT in clinical diagnosis.

Chemiluminescence and electrochemiluminescence detection of controlled drugs

We review the determination of various controlled drugs (opioids, tranquilizers, stimulants, and hallucinogens) using flow-analysis methodologies (flow injection analysis, high performance liquid chromatography, capillary electrophoresis, and microfluidic devices) with chemiluminescence and electrochemiluminescence reagents such as luminol, diaryloxalates, tris(2,2'-bipyridine)ruthenium(II), permanganate, manganese(IV), and sulfite, for industrial, clinical, pharmaceutical, and forensic science applications.

Determination of morphine in the plasma of addicts in using Zeolite Y extraction following high-performance liquid chromatography

BACKGROUND

The measurement of morphine in biological samples has become a routine in many clinical and forensic toxicology laboratories. A high-performance liquid chromatography (HPLC) method was developed for the determination of morphine in plasma.

METHODS

Samples were extracted using Zeolite Y column followed by reversed phase HPLC with fluorescence detection. This method was based on an ex-calibration procedure and was linear between 20 and 200 ng/ml of morphine. Blood from 10 male opiate addicts were obtained from Rosbeh Hospital. All of the male smoked opiate (heroin, opium) and cigarettes.

RESULTS

The mean total level 5 h after the last abuse was 152.4 ng/ml and 37.6 ng/ml at 10-15 h. The method was reliable for morphine determination in blood even after 5 half-lives after the last abuse.

CONCLUSIONS

This method is simple and rapid and may be useful for routine monitoring of plasma morphine concentration.

Amperometric detection of morphine at a Prussian blue-modified indium tin oxide electrode

In this work, the electrocatalytic oxidation of morphine (MO) at an optically transparent indium tin oxide (ITO) electrode modified by an electrodeposited Prussian blue (PB) thin film is first demonstrated, and the amperometric detection of MO was then investigated. Experimental results showed that the thin film on the ITO surface, confined to the PB/Berlin green (BG) redox pair, can serve as an excellent mediator which facilitates electron transfer and considerably lowers the overpotential required, as compared to a bare ITO electrode. Thus, PB can be regarded as a promising artificial peroxidase for MO. The rate of such an electrocatalytic reaction is pH dependent with the highest value at pH 5. By potential-step excitation from 0.55 to 0.70 V, a linear calibration curve, displaying the relationship between steady-state currents and MO concentrations (ranging from 0.09 to 1.0 mM), was obtained. The detection sensitivity is about 16.8 microA/cm2 mM. Most importantly, the method described herein can readily discriminate MO analogs lacking the phenolic -OH group, such as codeine, and can thus benefit the specific recognition of MO.

Determination of morphine by high-performance liquid chromatography with electrochemical detection: application to human and rabbit pharmacokinetic studies

A rapid, sensitive, precise and accurate high-performance liquid chromatographic assay with coulometric electrochemical detection was developed for the determination of morphine in human, rabbit, pig and dog plasma. It includes a one-step extraction procedure with hexane-isoamyl alcohol (1:1, v/v) at pH 8.9 (adjusted with phosphoric acid) and reversed-phase liquid chromatography on a microPorasil column. The mobile phase was composed of 5 mM sodium acetate buffer (pH 3.75)-acetonitrile (25:75, v/v). A flow-rate of 1.2 ml/min at 20 degrees C was used. The working potentials for the electrochemical detector were +0.20 V for detector cell 1, +0.55 V for detector cell 2 and +0.75 V for the guard cell. The limit of detection of morphine was 100 pg/ml of plasma. Repeatability, precision and accuracy were also determined concomitantly. The calibration graphs were linear in the concentration range 0.25-250 ng/ml with correlation coefficients of 0.998+/-0.01 and with a minimum intercept of 0.05+/-0.08. The precision in plasma was acceptable, with coefficients of variation less than 11%. The absolute recoveries of morphine and nalbuphine (internal standard) were between 86 and 89% and independent of morphine concentration. Pharmacokinetics after oral morphine [MST Continus (morphine sulphate tablets) 30 mg, Bard Pharmaceutical, Cambridge, UK] in humans revealed a one-compartment first-order absorption model with one absorption phase and one elimination phase. The absorption and elimination half-lives were 2.46 and 1.80 h, respectively. Pharmacokinetics after intravenous morphine (3 mg/kg) in rabbits showed a linear two-compartment open model with one distribution phase and one elimination phase. The distribution and elimination half-lives were 0.5 and 33.8 h, respectively.

Determination of morphine in urine by solid-phase immunoextraction and high-performance liquid chromatography with electrochemical detection

The analysis of morphine in biological fluids is of vital interest in monitoring opiate abuse and in drug abuse research. Although methods for analysis of morphine and its metabolites are well established, studies are still being carried out to improve sample preparation procedures as well as detection levels of morphine in biological samples. In this study, morphine-specific immunosorbents were developed to concentrate morphine prior to HPLC analysis. Urine (0.1 ml) was diluted 10-fold with phosphate-buffered saline, pH 7.4 (PBS), loaded onto a solid-phase immunoextraction column and washed with 15 ml PBS followed by elution with 2 ml of elution buffer (40% ethanol in PBS, pH 4). The eluted fraction was analysed for morphine by HPLC-electrochemical detection using a cyanopropyl (CN) analytical column with 25% acetonitrile in phosphate buffer-sodium lauryl sulphate, pH 2.4 as the mobile phase. Duration of the extraction procedure was approximately 40 min. Calibration graphs were linear from 100 ng ml-1 to 500 ng ml-1 in urine. The inter-assay R.S.D. was < 10% and the recovery of morphine from urine was > 98%. Immunocolumns demonstrated remarkably high specificity towards morphine showing minimal binding with other opiate metabolites such as codeine, normorphine, norcodeine, morphine-3-glucuronide, morphine-6-glucuronide.

Determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide in human serum by solid-phase extraction and liquid chromatography-mass spectrometry with electrospray ionisation

A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of morphine and two of its metabolites, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), in serum is described. The compounds are extracted from serum using Sep-Pak light C18 solid-phase extraction cartridges, separated on an ODS C18 analytical column (100 x 4.6 mm I.D.) and detected by electrospray ionisation mass spectrometry. The separation was achieved by running a linear gradient from 4 to 70% acetonitrile with formic acid added as modifier. The flow-rate in the column was 1.0 ml/min. After the column, the eluate was subjected to a 1:50 split, with 20 microliters/min delivered to the mass spectrometer and 980 microliters/min delivered to waste. The compounds were detected in the mass spectrometer by selected-ion monitoring for m/z 286.2 for morphine and 462.2 for M3G and M6G. The spray voltage was 2.4 kV and the sampling cone was set at 40 V. The compounds have been quantified in serum over a concentration range of 2.9-60 nmol/l (0.84-17 ng/ml) for morphine, 11-1080 nmol/l (5.0-500 ng/ml) for M3G and 4.3-220 nmol/l (2.0-100 ng/ml) for M6G using external standardisation. Intra-assay and inter-assay precision were in the range of 2.4-9.0% for all compounds. The major advantage with the present LC-MS method was the shorter analysis time, 10 min per sample compared to 45 min per sample with our previous LC method with dual detectors. The LC-MS method has proved to have both the selectivity and sensitivity needed for pharmacokinetic studies.

Rapid and highly automated determination of morphine and morphine glucuronides in plasma by on-line solid-phase extraction and column liquid chromatography

A high-performance liquid chromatography (HPLC) method has been developed for the determination of morphine and its main metabolites, morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G), in plasma or cerebrospinal fluid. Samples were extracted using on-line solid-phase extraction followed by reversed-phase HPLC with fluorescence detection. Recoveries of 20 ng morphine and morphine glucuronides in plasma were over 95%. The limit of detection using 400 microliters of a biological matrix was 0.85, 3.4 and 1.0 ng/ml of M-3-G, M-6-G and morphine, respectively. Inter- and intra-day assay precision was better than 10%. The main advantages of the present described method are increased recoveries (> 95%) and a high degree of automation allowing a high speed in routine analysis. The time required for the fully automated analysis of one sample was less than 26 min.

Reversed-phase high-performance liquid chromatography--photodiode-array analysis of alkaloid drugs of forensic interest

A reversed-phase high-performance liquid chromatography-photodiode-array method for the analysis of 23 drugs of forensic interest is presented. The separation method development was based on mobile-phase optimisation, temperature control and use of three ODS stationary phases. Multiwavelength detection and quantitation was performed at 225, 232, 239, 254, 275 and 289 nm. Absorbance rationing proved to be very helpful for the identification of these drugs. Recognition of the analysed compounds was achieved by means of correlation of retention time and absorbance ratios. The method was directly applied to the analysis of illicit heroin and cocaine samples and to the analysis of pharmaceutical preparations containing codeine.

An amperometric opiate assay

Current techniques for the detection and measurement of diacetylmorphine (heroin), morphine and their principal metabolite morphine-3-glucuronide (M3G) are based mainly on chromatography or immunoassay. No enzymatic method for the detection of these compounds has yet been reported. Two novel microbial enzymes have been isolated and characterized in this laboratory: an acetylmorphine carboxyesterase (heroin esterase) and a morphine dehydrogenase (MDH). These highly specific enzymes have been incorporated in an amperometric assay for heroin and morphine using phenazine methosulphate as a mediator. The assay gives a rapid and sensitive response to heroin and morphine, with a detection limit for morphine of 6.8 micrograms ml-1 (23.7 microM).

High-performance liquid chromatographic method for the quantitative determination of butorphanol, hydroxybutorphanol, and norbutorphanol in human urine using fluorescence detection

A sensitive, quantitative reversed-phase high-performance liquid chromatographic method has been established for the simultaneous determination of butorphanol, a synthetic opioid, and its metabolites, hydroxybutorphanol and norbutorphanol, in human urine samples. The method involved extraction of butorphanol, hydroxybutorphanol, and norbutorphanol from urine (1.0 ml), buffered with 0.1 ml of 1.0 M ammonium acetate (pH 6.0), onto 1-ml Cyano Bond Elut columns. The eluent was evaporated under nitrogen and low heat, and reconstituted with the HPLC mobile phase, acetonitrile-methanol-water (20:10:70, v/v/v), containing 10 mM ammonium acetate and 10 mM TMAH (pH 5.0). The samples were chromatographed on a reversed-phase octyl 5-microns column. The analysis was accomplished by detection of the fluorescence of the three analytes, at excitation and emission wavelengths of 200 nm and 325 nm, respectively. The retention times for hydroxybutorphanol, norbutorphanol, the internal standard, and butorphanol were 5.5, 9.0, 13.0, and 23.4 min respectively. The validated quantitation range of the method was 1-100 ng/ml for butorphanol and hydroxybutorphanol, and 2-200 ng/ml for norbutorphanol in urine. The observed recoveries for butorphanol, hydroxybutorphanol, and norbutorphanol were 93%, 72%, and 50%, respectively. Standard curve correlation coefficients of 0.995 or greater were obtained during validation experiments and analysis of study samples. The method was applied on study samples from a clinical study of butorphanol, providing a pharmacokinetic profiling of butorphanol.

Determination of morphine-3-glucuronide in human urine by capillary zone electrophoresis and micellar electrokinetic capillary chromatography

Attempts to determine morphine-3-glucuronide (MO3G) by high-performance capillary electrophoresis and micellar electrokinetic capillary chromatography are reported. Using direct injection of urine, it was possible to achieve a limit of detection of about 20 micrograms/ml, which is poor compared with high-performance liquid chromatography and immunoassays. However, employing sample extraction with C8 cartridges, the presence of MO3G in urines that tested positive for opioids using a commercial enzyme-multiplied immunoassay technique could be successfully confirmed. The limit of detection with unambiguous identification of MO3G via spectral analysis was about 1 microgram/ml.

Evaluation of a method for simultaneous quantification of codeine, dihydrocodeine, morphine, and 6-monoacetylmorphine in serum, blood, and postmortem blood

A solid-phase extraction and gas chromatographic-mass spectrometric method for the simultaneous determination of codeine, dihydrocodeine, morphine, and 6-monoacetylmorphine in serum, blood or postmortem blood is described. The extraction technique allows the determination of free or total morphine (morphine plus morphine glucuronide). Experiments with spiked blood samples resulted in recoveries of 96.4% +/- 4.2% for codeine, 95.8% +/- 5.1% for dihydrocodeine, 90.3% +/- 7.8% for 6-monoacetylmorphine and 92.5% +/- 8.1% for morphine. Excellent linearity was obtained over the range 1-1500 ng/mL. The detection limit for all analytes is less than 1 ng/mL.

Simultaneous measurement of extracellular morphine and serotonin in brain tissue and CSF by microdialysis in awake rats

In this report, we describe an HPLC with electrochemical detection assay for the simultaneous measurement of levels of morphine, serotonin, 5-hydroxyindole-3-acetic acid, and homovanillic acid in dialysates of various brain areas and CSF in the awake rat. Morphine could be detected in the dialysates after a single intraperitoneal injection, with doses as low as 1.0 mg/kg. The time course of extracellular morphine content in the lateral hypothalamus, striatum, cerebellum, periaqueductal gray, and dorsal horn of the spinal cord and in CSF, from the ventricles and cisterna magna, was similar. We detected morphine in the first 15-min sample, and levels peaked 45-60 min after injection. Maximal dialysate levels, however, varied with the type of dialysis probe used and the area sampled. The most efficient in vivo recovery was in CSF dialysates from the cisterna magna, presumably because of minimal tissue interference with the dialysis probe. For this reason, the cisterna is an ideal region for sampling CSF. Morphine had no significant effect on the extracellular concentrations of serotonin in any of the areas studied and did not modify or only slightly increased levels of tissue metabolites; however, morphine markedly increased the CSF levels of 5-hydroxyindole-3-acetic acid and homovanillic acid. Because microdialysis in freely moving animals permits assessment of the behavioral effects of morphine while continuously monitoring the drug levels in discrete brain regions, this approach will greatly facilitate future studies of the neurochemical basis of morphine's effects in the brain.

High-performance liquid chromatographic determination of morphine, morphine-3-glucuronide, morphine-6-glucuronide and codeine in biological samples using multi-wavelength forward optical detection

An isocratic high-performance liquid chromatographic method has been developed for the determination of morphine, morphine-3-glucuronide, morphine-6-glucuronide and codeine in plasma, urine and cerebrospinal fluid. The use of an efficient solid-phase extraction procedure together with a forward optical scanning detector allows a detection limit of 500 pg/ml. The method was evaluated by examination of biological samples taken from newborn infants following the intravenous administration of morphine sulfate.

Simple method for the determination of morphine and its active glucuronide metabolite in human plasma by high-performance liquid chromatography with electrochemical detection

A simple method for the simultaneous determination of morphine and its pharmacologically active metabolite morphine-6-glucuronide in 0.5 ml human plasma is described. It is based on the method of Svensson [J. Chromatogr., 230 (1982) 427 and 375 (1986) 174], but uses only one solid-phase extraction cartridge prior to chromatography and only a 20-microliter injection volume. Mean recoveries of 90 and 85% for morphine and morphine-6-glucuronide, respectively, were obtained, the limit of detection being 2 nmol/l (at a signal-to-noise ratio of 3.0).

Determination of morphine and 6-acetylmorphine in plasma by high-performance liquid chromatography with fluorescence detection

A method is described for the simultaneous determination of morphine and 6-acetylmorphine in small volumes of human plasma by normal-phase high-performance liquid chromatography using solid-phase extraction, dansyl derivatisation and fluorescence detection. The lower limits of quantitation in a 0.1-ml plasma sample are 10 ng/ml for morphine and 25 ng/ml for 6-acetylmorphine. The method has been applied to determine concentrations of morphine and 6-acetylmorphine in plasma samples from premature babies administered an intravenous infusion of diamorphine.

Direct injection high-performance liquid chromatographic assay of morphine with electrochemical detection, a polymeric column and an alkaline eluent

A simple method is described for the direct determination of morphine in untreated plasma or serum, using reversed-phase high-performance liquid chromatography with amperometric electrochemical detection. A basic eluent [0.05 mol/l phosphate buffer-isopropanol-tetrahydrofuran (88:10:2) (pH 9.5)] allows both reversed-phase chromatography of morphine under ionization control conditions and its detectability at an unprotected thin-layer glassy carbon electrode at a potential of 350 mV (vs. an Ag/AgCl reference electrode). In addition, the alkaline mobile phase promotes the ionization of serum proteins, which, being poorly retained by the hydrophobic column packing [poly(styrene-divinylbenzene) copolymer], elute early in the chromatogram, leaving a clean baseline. Up to 50 microliters of simply filtered plasma can be injected. The absolute limit of detection is 0.75 ng on-column. No interferences were observed from more than 80 opiate and non-opiate drugs. The intra- and inter-assay relative standard deviations (n = 5) were 3.2 and 6.6%, respectively, at a morphine concentration of 100 ng/ml in plasma and 0.09 and 4.2%, respectively, at the level of 500 ng/ml.