Determination Of Opiates Research Articles

Determination of opiates in urine samples using a composite of covalent organic framework and polypyrrole as a sorbent for microextraction in a packed syringe combined with HPLC/UV

This study aimed to develop microextraction in a packed syringe (MEPS) method for the determination of the three opiates in urine samples. Covalent organic framework-polypyrrole- cetyltrimethylammonium bromide (COF-PPy-CTAB) nanocomposite, as an appropriate and highly efficient adsorbent, was synthesized and applied to the MEPS process. The analytes were separated and extracted on the solid phase surface of the adsorbent through π stacking, hydrophobic, and host-guest interaction and then eluted by a desorbing solvent. After synthesizing the composite and using it in the syringe as a substrate for analyte adsorption, the parameters affecting the extraction of the analytes were optimized and the calibration curve was obtained according to the optimum conditions. The results were linear in the concentration range of 0.5–1000 μg L − 1 with a coefficient of determination greater than 0.9945. The limits of detection and quantification were obtained in the range of (0.1–1.0) and (0.5–5.0) μg L‒1, respectively. The precision of the work was obtained for a syringe in a day and between days and also syringe to syringe in the range of 4.4–6.1%, 6.5–8.1%, and 7.8–10.1%, respectively. The preconcentration factors of 17, 20, and 16 were obtained for codeine, papaverine, and naltrexone, respectively. Relative recoveries of the drugs from urine samples were in acceptable range of 94.4–100.6% for codeine, 99.3–103.1% for papaverine and 95.0–98.9% for naltrexone.

Determination of opiates in whole blood using microextraction by packed sorbent and gas chromatography-tandem mass spectrometry

In Portugal, and worldwide, the abuse of psychoactive substances is increasing, with a significant incidence of deaths related to their consumption. Opiates are one of the most prevalent group of substances in that context, and they are responsible for a significant impact of the mentioned harms. Therefore, it becomes necessary to equip labs with faster and effective methods to identify and quantify these substances. This work describes the development and validation of a novel analytical method for the simultaneous determination of morphine, codeine and 6-monoacetylmorphine in blood samples by gas chromatography-tandem mass spectrometry (GC–MS/MS), using microextraction by packed sorbent (MEPS) for sample preparation. Before the MEPS procedure, a precipitation step with acetonitrile was performed. The MEPS parameters were optimized using the fractional factorial planning (2k-1) and surface response methodology. The final optimized conditions were: number of strokes (20), amount of formic acid in the washing solution (3.36%), number of washes of the sorbent (1), amount of ammonium hydroxide in the elution solution (2.36%) and number of elution cycles (11). After the extraction procedure, the analytes were derivatized with MSTFA with 5% TMS. Using a sample volume of 250 μL, the method was validated according to internationally accepted standards. The method proved to be linear in the range of 5-1000 ng/mL with coefficients of determination greater than 0.99 for all analytes. Intra-and inter-day precision and accuracy were in accordance with the above-mentioned criteria, presenting coefficients of variation ≤15% and relative errors within a range of ± 15% of the theoretical concentration. The absolute recoveries ranged from 6 to 23%. The validated method was applied to the analysis of real samples, being an advantageous tool for the detection of those substances in blood. This is the first time that GCMS/MS with MEPS was used for the determination of these compounds in biological fluids.

QuEChERS sample preparation prior to LC-MS/MS determination of opiates, amphetamines, and cocaine metabolites in whole blood.

Modern LC-MS/MS instruments have sensitivity and scanning velocity high enough to analyze many different compounds in single runs. Consequently, the sample preparation procedure has become the bottleneck for developing efficient, rapid, and cheap multi-compound methods. Here, we examined one-step sample preparation based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) salts to set up and validate a LC-MS/MS method for the simultaneous determination of 35 drugs of abuse and their metabolites in whole blood. Despite large differences in physicochemical properties, this simplified QuEChERS extraction method yielded satisfactory recoveries (until 96%) for the 35 molecules. The amounts of QuEChERS salts had no influence on extraction yield. Chromatographic separation was obtained in less than 6 min. LLOD and LLOQ were 3 and 5 ng/mL, respectively. The procedure was successfully validated and then applied to 253 cases of driving under the influence of drugs (DUID), collected over a 6-month period.

Determination of Opiates in Whole Blood and Vitreous Humor: A Study of the Matrix Effect and an Experimental Design to Optimize Conditions for the Enzymatic Hydrolysis of Glucuronides

Undoubtedly, whole blood and vitreous humor have been biological samples of great importance in forensic toxicology. The determination of opiates and their metabolites has been essential for better interpretation of toxicological findings. This report describes the application of experimental design and response surface methodology to optimize conditions for enzymatic hydrolysis of morphine-3-glucuronide and morphine-6-glucuronide. The analytes (free morphine, 6-acetylmorphine and codeine) were extracted from the samples using solid-phase extraction on mixed-mode cartridges, followed by derivatization to their trimethylsilyl derivatives. The extracts were analysed by gas chromatography-mass spectrometry with electron ionization and full scan mode. The method was validated for both specimens (whole blood and vitreous humor). A significant matrix effect was found by applying the F-test. Different recovery values were also found (82% on average for whole blood and 100% on average for vitreous humor). The calibration curves were linear for all analytes in the concentration range of 10-1,500 ng/mL. The limits of detection ranged from 2.0 to 5.0 ng/mL. The method was applied to a case in which a victim presented with a previous history of opiate use.

Determination of opiates and cocaine in hair using automated enzyme immunoassay screening methodologies followed by gas chromatographic–mass spectrometric (GC–MS) confirmation

The objective of this study was to develop a two-step strategy for analysis of opiates and cocaine in hair samples involving an immunological screening procedure followed by confirmation of results using gas chromatography–mass spectrometry (GC–MS). A semi-quantitative automated competitive enzyme-linked immunosorbent assay (ELISA) methodology using Oral Fluid Micro-Plate Enzyme Immunoassays (Orasure Technologies, Inc.) was developed and validated. Applicability was proven by analysis of authentic head hair samples from drug users ( n = 103) and from opiate associated fatalities ( n = 21). The optimum cutoff values for the ELISA tests were 0.1 ng cocaine-equivalents/mg hair and 0.05 ng morphine-equivalents/mg hair using a 50 mg hair sample. Both ELISA tests had a sensitivity of 100%, the specificity was 66% for cocaine-equivalents and 42% for morphine-equivalents. The intraassay precision was 11% for the cocaine and 3% for the opiates ELISA, while interassay precision was 12% for the cocaine and 4% for the opiates ELISA test. The actual analyte concentrations in the hair samples were determined using GC–MS and were between 0.04 and 5.20 ng/mg for heroin (HER), between 0.04 and 30.01 ng/mg for 6-monoacetylmorphine (MAM), between 0.03 and 11.87 ng/mg for morphine (MOR), between 0.02 and 1.84 ng/mg for codeine (COD), between 0.02 and 2.48 ng/mg for acetylcodeine (AC), between 0.01 and 21.37 ng/mg for cocaine (COC), between 0.03 and 10.51 ng/mg for benzoylecgonine (BE) and between 0.05 and 1.26 ng/mg for cocaethylene (CE). The automated ELISA tests were proven to be valid screening procedures for the detection of cocaine and opiates in hair as confirmed by GC–MS. Screening methods provide rapid and inexpensive automated pre-test procedures to detect drugs in hair or other matrices. For forensic purposes screening therefore represents an ideal complement to routinely applied GC–MS procedures.

Retention Time Locking in the Determination of Narcotic Drugs by Chromatography and Chromatography–Mass Spectrometry

The use of retention time locking (RTL) in the development of unified procedures for the detection and quantitative determination of drugs in biological fluids was considered. With consideration for the use of RTL, a chromatographic procedure with flame-ionization and mass-selective detection was developed for the detection and quantitative determination of opiates and their synthetic analogs; phenylalkylamine derivatives; cocaine; ketamine; and other narcotic drugs, their derivatives, and metabolites in urine. The analytical ranges for chromatography–mass spectrometry were 0.05–1000 and 0.005–1000 μg/mL under the conditions of total ion current (TIC) scanning and selected ion monitoring (SIM), respectively. With flame-ionization detection (GC–FID), the analytical range was 0.5–1000 μg/mL.

Determination of opiates in postmortem bone and bone marrow

Bone and bone marrow of a fatally poisoned heroin addict were analyzed by FPIA and GC-FID, immediately after death. A piece of the bone from the above case was buried for 1 year and analyzed by the same procedure. Morphine was detected in all specimens at concentrations of 195, 340 and 155 ng/g for bone marrow, bone and buried bone, respectively. A loss of 54.4% of morphine concentration was observed during 1-year burial. Such findings have potential forensic value in cases of skeletonized remains.

Determination of opiates and cocaine in hair as trimethylsilyl derivatives using gas chromatography-tandem mass spectrometry.

An analytical method for the determination of heroin, 6-monoacetylmorphine, morphine, codeine, cocaine, benzoylecgonine, and cocaethylene in human hair using gas chromatography-tandem mass spectrometry is presented. The analytes were extracted from finely cut hair with methanol at 56 degrees C for 18 h in the presence of nalorphine as the internal standard. After the incubation, methanol was evaporated to dryness, and all the analytes, except heroin, cocaine, and cocaethylene, were converted to their trimethylsilyl derivatives. The reaction products were identified and quantitated using product ions formed from the parent ions by collision-induced dissociation in the ion-trap mass spectrometer. This method provided excellent sensitivity and specificity for analytes at the concentrations usually found in the keratin matrix.

Determination of opiates in hair. Effects of extraction methods on recovery and on stability of analytes

In order to evaluate (i) the recovery of extraction of opiates from authentic hair samples and (ii) the extent of hydrolysis of acetylated opiates (6-acetylmorphine, acetylcodeine) occurring during sample preparation, three different methods of extraction commonly used for opiates have been compared. To this purpose a sample consisting of a pool of hair collected from several heroin overdose cases has been submitted alternately to (A) digestion in 2 M NaOH at 80 °C for 1 h ( n = 5), (B) incubation in 0.1 M HCl at 45 °C for 18 h ( n = 5) and (C) incubation in methanol at 37 °C for 18 h ( n = 5). After pH adjustment of the different incubation media to 7–8, analytes have been isolated by means of SPE using Bond Elut certify columns and derivatized with MSTFA. Analyses have been performed by either GC-MS in the selected ion monitoring mode or, omitting SPE, by radioimmunoassay. The extent of hydrolysis of 6-acetylmorphine to morphine and of acetylcodeine to codeine have been determined by submitting blank hair samples spiked with the acetylated analytes to the different extraction methods and measuring the amount of morphine and codeine formed. Both the recovery of extraction of the total morphine fraction (6-acetylmorphine + morphine) and the rate of hydrolysis of 6-acetylmorphine were found to be in the order: A > B > C. Similar results were obtained for the total codeine fraction (acetylcodeine + codeine). These results clearly indicate that: (i) the concentration of opiates measured in hair depends on the extraction method used; (ii) ratios between different analytes (e.g. 6-acetylmorphine vs. morphine) may reflect the rate of hydrolysis during sample preparation rather than different types of exposure to opiates.

Determination of opiates in urine by capillary electrophoresis

A method for the separation of a mixture of opiates comprising pholcodine, 6-monoacetylmorphine, morphine, heroin, codeine and dihydrocodeine by capillary electrophoresis using a running buffer of 100 mM disodium hydrogenphosphate at pH 6 is described. The characteristics of an analytical method based on this separation for the determination of these drugs following extraction from urine and using levallorphan as internal standard are reported. Detection limits in the region of 10 ng cm −3 are achieved when using electrokinetic injection. A comparison is made of the sensitivity and reproducibility of electrokinetic and hydrodynamic injection for these drugs. Data are presented to show the results obtained when the proposed method is applied to urine spiked with all the above opiates and also to urine from a subject following consumption of dihydrocodeine and pholcodine. The concentrations found are compared with those obtained by LC.

Comparison of quantitative results of drugs in human hair by [formula omitted

Until the first determination of opiates in human hair by GC MS in 1985, radioimmunological results of hair examinations met with opposition. Since then, further GC MS methods have been developed that have led not only to considerably increased sensitivity, but can also be used in hair analysis for screening purposes and can detect substances for which RIA kits are not available. In the present study different extraction methods were used along with two GC MS processes which back-up each other. These methods include the enzymatic dissolution of the hair, incubation with a buffer solution followed by a solid-phase extraction and incubation with methanol without a further extraction. The GC MS examination for heroin, cocaine, hashish and selected pharmaceuticals was carried out after derivatization with pentafluoropropionic acid anhydride or pentafluoro-1-propanol. Because of the higher sensitivity and versatility of GC MS , two GC MS processes were used to confirm each other instead of backing-up radioimmunological measurements with GC MS .

Determination of opiates and other basic drugs by high-performance liquid chromatography with electrochemical detection

A procedure is described for the extraction and determination of morphine (M), hydromorphone (HM), codeine (C) and metoclopramide (MCP) present in human plasma. The drugs are separated by reversed-phase liquid chromatography and detected amperometrically at a glassy carbon electrode. The method provides high sensitivity and selectivity and has been used successfully in bioavailability studies.

On-line electrochemical reagent production for detection in liquid chromatography and continuous flow systems

The on-line electrochemical production of bromine as a reagent for detection in liquid chromatography is studied. For detection, the excess of bromine after reaction with an analyte in the column effluent is measured amperometrically. Phenolic ethers are used as model compounds. The relations between generating current, reaction time, rate constant, signal and noise are investigated. Rate constants were measured in batch experiments with rotating ring-disk electrodes. Lower and upper limits of detection are predicted. Under favourable conditions, detection limits are shown to be in the subnanogram range. The optimal generating current, with respect to sensitivity and selectivity, is discussed in detail. The determination of opiates (morphine, codeine, noscapine and papaverine) is used an example of the efficacy of the method.

Determination of opiates in biological samples by glass capillary gas chromatography with electron-capture detection

A gas chromatographic method for the simultaneous determination of morphine, 6-acetylmorphine and codeine in human plasma or blood has been developed. The samples are buffered to pH 9 and extracted on silica columns, cleaned by extraction and finally acylated with pentafluropropionic anhydride. The derivatives formed are separated on a glass capillary column with falling glass needle injection and electron-capture detection. The choice of the extraction conditions and the preparation of suitable capillary columns are discussed.

Comparison of Results for Quantitative Determination of Morphine by Radioimmunoassay, Enzyme Immunoassay, and Spectrofluorometry

The quantitative results (accuracy and precision) for determination of opiates by radioimmunoassay (RIA), enzyme immunoassay (EMIT), and spectrofluorometry on split samples are compared. A variety of physiological samples were studied, including random urine from a methadone maintenance clinic and postmortem urine, blood, bile, brain, and lung tissue from heroin-induced or heroin-related deaths. The opiate concentrations detected by the two immunoassay methods were in good agreement with each other in the absence of interfering substances which are believed to react with the antimorphine antibodies. The immunoassay results were in agreement within the relative standard deviation with the fluorometry results in 55% of the urine samples and 80% of the blood samples. The immunological methods are superior to fluorometry for quantitation of morphine in urine samples due to quenching interferences in fluorometry from urine. They were comparable to fluorometry for quantitation of morphine in blood samples.

Separation and determination of opiates and diluents in illicit narcotic mixtures

A semi-automated method for the separation and determination of opiates in illicit narcotic preparations is described. The procedure involves resolution of the mixtures on SE-Sephadex ion-exchanger, continuous ultraviolet monitoring of the column effluent and colorimetric assay of lactose and mannitol. Peak elution volumes ( V e ) for compounds of forensic importance are presented. The differences in V e 's for the most commonly encountered opiates and diluents are great enough to permit identification and determination with ease. Examples of analyses of contraband preparations are also discussed.