Position of chromatographic techniques in screening for detection of drugs or poisons in clinical and forensic toxicology and/or doping control

Author(s):  
Hans H. Maurer

AbstractThis paper reviews chromatographic screening procedures for simultaneous detection of several drug classes relevant to clinical and forensic toxicology or doping control in urine or blood using gas chromatography-mass spectrometry (GC-MS), liquid chromatography coupled with a diode-array detector (LC-DAD) or a mass spectrometer (LC-MS). The pros and cons of the different techniques and procedures are discussed leading to the following conclusions and perspectives. GC-MS, especially in the electron ionization full-scan mode, is still the method of choice for comprehensive screening providing best separation power, specificity and universality, although requiring derivatization. LC-DAD is also often used for screening, but its separation power and its specificity are still inferior to those of GC-MS. Finally, LC-MS has shown to be an ideal supplement, especially for the detection of more polar, thermolabile and/or low-dose drugs, especially in blood plasma. It may become the gold standard in clinical and forensic toxicology and doping control if, at a later date, the costs of the apparatus will be markedly reduced, the current disadvantages like irreproducibility of fragmentation, reduction of ionization by matrix, etc. will be overcome, and finally if one of the increasing number of quite different techniques will become the apparatus standard.

2020 ◽  
Vol 71 (1) ◽  
pp. 48-55 ◽  
Author(s):  
Reza Mohammadzaheri ◽  
Mehdi Ansari Dogaheh ◽  
Maryam Kazemipour ◽  
Kambiz Soltaninejad

AbstractDiazinon poisoning is an important issue in occupational, clinical, and forensic toxicology. While sensitive and specific enough to analyse diazinon in biological samples, current methods are time-consuming and too expensive for routine analysis. The aim of this study was therefore to design and validate a simple dispersive liquid-liquid microextraction (DLLME) for the preparation of urine samples to be analysed for diazinon with high performance liquid chromatography with diode-array detector (HPLC-DAD) to establish diazinon exposure and poisoning. To do that, we first identified critical parameters (type and volume of extraction and disperser solvents, pH, surfactant, and salt concentrations) in preliminary experiments and then used central composite design to determine the best experimental conditions for DLLME-HPLC-DAD. For DLLME they were 800 µL of methanol (disperser solvent) and 310 µL of toluene (extraction solvent) injected to the urine sample rapidly via a syringe. The sample was injected into a HPLC-DAD (C18 column, 250×4.6 mm, 5 μm), and the mobile phase was a mixture of acetonitrile and buffer (63:37 v/v, pH 3.2; flow rate: 1 mL/ min). Standard calibration curves for diazinon were linear with the concentration range of 0.5–4 µg/mL, yielding a regression equation Y=0.254X+0.006 with a correlation coefficient of 0.993. The limit of detection and limit of quantification for diazinon were 0.15 µg/mL and 0.45 µg/mL, respectively. The proposed method was accurate, precise, sensitive, and linear over a wide range of diazinon concentrations in urine samples. This method can be employed for diazinon analysis in routine clinical and forensic toxicology settings.


Author(s):  
Ahmad Shekari ◽  
Rooholah Valipour ◽  
Mehrdad Setareh ◽  
Kambiz Soltaninejad

Background: Methadone abuse and dependence has been reported as a growing concern in some countries. In present study, a rapid, simple, easy and sensitive method for determination of methadone in human urine samples for use in clinical and forensic toxicology and drug screening laboratories was developed and validated. Methods: We determined methadone in urine sampled by gas chromatography/mass spectrometry (GC/MS) and used ultrasound assisted liquid-liquid extraction (UALLE) method for the extraction and preconcentration of methadone before analysis. Results: The limit of detection was 2.1 ng/mL and the limit of quantification 7 ng/mL. Correlation coefficient was 0.9984 for the methadone calibration curve in linear range from 7 to 10,000 ng/mL. The method is accurate and precise. Recovery was in the range of  81.3 % to 97.4 % and enrichment factor was 8.7. The method was successfully applied for determining methadone in clinical and postmortem urine samples. Conclusions: The present method is a rapid, simple, easy and sensitive procedure and can be used in clinical and forensic toxicology laboratories as routine method for qualitative and quantitative analysis of methadone.  


1994 ◽  
Vol 40 (2) ◽  
pp. 216-220 ◽  
Author(s):  
A H Wu ◽  
D Ostheimer ◽  
M Cremese ◽  
E Forte ◽  
D Hill

Abstract Interference by substances coeluting with targeted drugs is a general problem for gas chromatographic/mass spectrometric analysis of urine. To characterize these interferences, we examined human urine samples containing benzoylecgonine and fluconazole, and other drug combinations including deuterated internal standards that coelute (ISd,c) with target drugs, by selected-ion monitoring (SIM) and full-scan mass spectrometry. We show that, by SIM analysis, detecting the presence of an interferent is dependent on the specific IS used for the assay. When an ISd,c is used, the presence of another coeluting substance (interferent) suggests that the intensity of IS ions is substantially diminished, because the interferent affects both the ISd,c and target drug. When a noncoeluting IS (ISnc) is used, the interferent cannot be discerned unless it coincidently contains one or more of the ions monitored for either the target drug or ISnc. Under full-scan analysis, a coeluting interferent is directly discernable by examining the total ion gas chromatogram.


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