Forensic Toxicology

Kostakis, Chris; Harpas, Peter; Stockham, Peter

doi:10.1016/b978-0-12-415806-1.00010-3

Cited by 3 publications

(2 citation statements)

References 161 publications

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“…Chloroform has been routinely used for the initial step in extraction and derivatization for the detection of illicit drugs using GC-MS and LC-MS. [21] In addition to chloroform, successful extractions have been performed with diethyl ether, heptane, toluene and other solvents. [22] Figure S4 displays observed spectra for chloroform and toluene extractions for methadone spiked saliva. Toluene extraction ( Figure S4A) produced a noisy/convoluted spectrum compared to chloroform extraction of methadone at 100 ng/mL ( Figure 3B).…”

Section: Reproducibility Of Psi Saldi-ms For Methadone Detectionmentioning

confidence: 99%

Porous silicon mass spectrometry as an alternative confirmatory assay for compliance testing of methadone

Guinan

Neldner

Stockham

et al. 2016

Drug Testing and Analysis

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Porous silicon based surface-assisted laser desorption ionization mass spectrometry (pSi SALDI-MS) is an analytical technique well suited for high throughput analysis of low molecular weight compounds from biological samples. A potential application of this technology is the compliance monitoring of opioid addiction programmes, where methadone is used as a pharmacological treatment for drugs such as heroin. Here, we present the detection and quantification of methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) from water and clinical samples (saliva, urine, and plasma) from opioid dependent participants using pSi SALDI-MS. A one-step solvent phase extraction using chloroform was developed for the detection of methadone from clinical samples for analysis by pSi SALDI-MS. Liquid chromatography-mass spectrometry (LC-MS) was used as a comparative technique for the quantification of methadone from clinical saliva and plasma samples. In all cases, we obtained a good correlation of pSi SALDI-MS and LC-MS results, suggesting that pSi SALDI-MS may be an alternative procedure for high-throughput screening and quantification for application in opioid compliance testing. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Reproducibility Of Psi Saldi-ms For Methadone Detectionmentioning

confidence: 99%

Porous silicon mass spectrometry as an alternative confirmatory assay for compliance testing of methadone

Guinan

Neldner

Stockham

et al. 2016

Drug Testing and Analysis

View full text Add to dashboard Cite

show abstract

“…Laboratory analysis for drugs of abuse (the second tier) is typically implemented by gas chromatography (GC) or high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (MS/MS). , These methods are extremely precise and reproducible, representing the analytical “gold standard” for confirmatory analysis. ,, However, these methods are slow (often requiring extensive sample processing prior to analysis), must be performed by well-trained technicians, and require use and maintenance of expensive laboratory equipment. Various strategies have been used in an attempt to reduce analysis times, including “dilute-and-shoot” protocols in which the sample is simply diluted and then analyzed by HPLC–MS/MS. , While this circumvents sample processing, these protocols are not ideal for quantifying low concentrations and the methods require chromatographic separation which is often the rate-limiting step in the analysis (30–60 min per sample).…”

mentioning

confidence: 99%

Analysis on the Go: Quantitation of Drugs of Abuse in Dried Urine with Digital Microfluidics and Miniature Mass Spectrometry

et al. 2014

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We report the development of a method coupling microfluidics and a miniature mass spectrometer, applied to quantitation of drugs of abuse in urine. A custom digital microfluidic system was designed to deliver droplets of solvent to dried urine samples and then transport extracted analytes to an array of nanoelectrospray emitters for analysis. Tandem mass spectrometry (MS/MS) detection was performed using a fully autonomous 25 kg instrument. Using the new method, cocaine, benzoylecgonine, and codeine can be quantified from four samples in less than 15 min from (dried) sample to analysis. The figures of merit for the new method suggest that it is suitable for on-site screening; for example, the limit of quantitation (LOQ) for cocaine is 40 ng/mL, which is compatible with the performance criteria for laboratory analyses established by the United Nations Office on Drugs and Crime. More importantly, the LOQ of the new method is superior to the 300 ng/mL cutoff values used by the only other portable analysis systems we are aware of (relying on immunoassays). This work serves as a proof-of-concept for integration of microfluidics with miniature mass spectrometry. The system is attractive for the quantitation of drugs of abuse from urine and, more generally, may be useful for a wide range of applications that would benefit from portable, quantitative, on-site analysis.

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An alternative approach for assessment of liquid chromatography-mass spectrometry matrix effects using auto-sampler programmed co-injection

et al. 2016

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We report the use of auto-sampler programmable functions to co-inject analyte standard solution and matrix extract to assess ion enhancement and suppression (matrix effects) in LC-MS. This is effectively an automated post-extraction addition (APEA) procedure, emulating the manual post-extraction addition (PEA) approach widely adopted for assessment of matrix effects. To verify that APEA was comparable to the conventional PEA approach, matrix effects were determined using both methods for a selection of 31 illicit and pharmaceutical drugs in 10 different human urine extracts. Matrix effects measured using APEA were statistically indistinguishable from manual PEA methodology for 27 of the 31 drugs. Of the four drugs that showed significant differences using the two methods, three differed by less than 2 %, which is within the expected accuracy limits required for matrix effect determinations. The remaining analyte, trimeprazine, was found to degrade in the spiked PEA matrix extract, accounting for the difference between matrix effects measured by the PEA and APEA approaches. APEA enables a single matrix extract to be assessed at multiple analyte concentrations, resulting in a considerable reduction in sample preparation time. In addition, APEA can reduce the quantity of analyte-free sample matrix required for matrix effect assessment, which is an important consideration in certain analytical and bioanalytical fields. This work shows that APEA may be considered as an acceptable alternative to PEA for the assessment of matrix effects in LC-MS method validation and may be applicable to a variety of matrices such as environmental samples.

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Forensic Toxicology

Cited by 3 publications

References 161 publications

Porous silicon mass spectrometry as an alternative confirmatory assay for compliance testing of methadone

Porous silicon mass spectrometry as an alternative confirmatory assay for compliance testing of methadone

Analysis on the Go: Quantitation of Drugs of Abuse in Dried Urine with Digital Microfluidics and Miniature Mass Spectrometry

An alternative approach for assessment of liquid chromatography-mass spectrometry matrix effects using auto-sampler programmed co-injection

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