Extraction and analysis of clonazepam and 7-aminoclonazepam in whole blood using a dual internal standard methodology

Hackett, Jeffery; Elian, Albert A.

doi:10.1016/j.forsciint.2006.05.040

Cited by 10 publications

(6 citation statements)

References 12 publications

(16 reference statements)

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“…The extraction efficiency of QC by our method is higher in comparison to other published methods [6,12,21,22]. A review of these four studies with respect to the accuracy of benzodiazepine determination shows accuracies of 81-114% [6], 85-115% [12], 88-114% [21], and 83-93% [22]. Similar results of accuracy in the range of 92-112% have been reported with a mixed-mode SPE [23].…”

Section: Validation Of Methodssupporting

confidence: 76%

“…The developed method has been compared with previously described methods suitable for the determination of benzodiazepines in plasma or whole blood after SPE. The extraction efficiency of QC by our method is higher in comparison to other published methods [6,12,21,22]. A review of these four studies with respect to the accuracy of benzodiazepine determination shows accuracies of 81-114% [6], 85-115% [12], 88-114% [21], and 83-93% [22].…”

Section: Validation Of Methodsmentioning

confidence: 79%

“…Existing SPE procedures for benzodiazepines cover a broad range of sorbents (apolar, ion‐exchange, and polymeric sorbents or a combination of different sorbents) and allow the development of extraction procedures for specific needs . The sorbents used include silica‐based phases with bonded C1 , C2 , C18 , and phenyl ligands. A polymeric column, with a mixed‐mode cation‐exchange sorbent for determination of midazolam and its main metabolite , and a hydrophilic–lipophilic balanced polymeric column have also been used for sample preparation before HPLC or LC‐MS/MS analysis of benzodiazepines .…”

Section: Introductionmentioning

confidence: 99%

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Mixed‐mode SPE for a multi‐residue analysis of benzodiazepines in whole blood using rapid GC with negative‐ion chemical ionization MS

Karlonas

Padarauskas

Ramanavičius

et al. 2013

J of Separation Science

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A sensitive and selective method for simultaneous quantitation of 15 benzodiazepines in human whole blood using rapid GC with negative-ion chemical ionization MS is proposed. A mixed-mode cation-exchange polymeric sorbent was used for SPE. Different extraction solvents or mixtures of solvents of different compositions for elution of the adsorbed analytes, and washing steps for eliminating interferences in the column were tested. Analytes were eluted from the column using 5% v/v NH4 OH in methanol. A derivatization step using different silylation reagents, time, and temperature was tested. Extracts from SPE were silylated by a mixture of N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide, acetonitrile, ethyl acetate, and subjected to gas chromatographic analysis. The LODs of 15 benzodiazepines in whole blood samples ranged from 0.24-0.62 ng mL(-1). The RSDs of samples used for three different quality control concentration levels were lower than 7.0%, and the accuracy ranged from 89.5 to 110.5%. The results show that the developed method is accurate, sensitive, selective, and very fast. Finally, the applicability of this method for determination of trace concentrations of several benzodiazepines in real blood samples has been demonstrated.

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Section: Validation Of Methodssupporting

confidence: 76%

Section: Validation Of Methodsmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mixed‐mode SPE for a multi‐residue analysis of benzodiazepines in whole blood using rapid GC with negative‐ion chemical ionization MS

Karlonas

Padarauskas

Ramanavičius

et al. 2013

J of Separation Science

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“…Overdoses of these drugs can cause acute symptoms; therefore, it is desirable to monitor their concentrations in the biological fluids . Various chromatographic methods have been employed to detect and to separate benzodiazepines from each other and other components in extracts such as HPLC , GC , UHPLC , and CE .…”

Section: Introductionmentioning

confidence: 99%

Surfactant-assisted dispersive liquid-liquid microextraction of nitrazepam and lorazepam from plasma and urine samples followed by high-performance liquid chromatography with UV analysis

et al. 2015

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Surfactant-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with UV detection has been developed for the simultaneous preconcentration and determination of lorazepam and nitrazepam in biological fluids. In this study, an ionic surfactant (cetyltrimethyl ammonium bromide) was used as an emulsifier. The predominant parameters affecting extraction efficiency such as the type and volume of extraction solvent, the type and concentration of surfactant, sample pH, and the concentration of salt added to the sample were investigated and opted. Under the optimum conditions (extraction solvent and its volume, 1-octanol, 70 μL; surfactant and its concentration, 1 mL of ultra-pure water containing 2 mmol L cetyltrimethyl ammonium bromide; sample pH = 9 and salt content of 10% NaCl w/v), the preconcentration factors were obtained in the range of 202-241 and 246-265 for nitrazepam and lorazepam, respectively. The limits of quantification for both drugs were 5 μg L in water sample and 10 μg L in biological fluids with R values higher than 0.993. The suitability of the proposed method was successfully confirmed by the extraction and determination of the target drugs in human urine and plasma samples in the range of microgram per liter.

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“…These methods often had a limit of quantitation (LOQ) of single or even sub-nanograms per milliliter; however, forensic laboratories without access to this novel technology may be many years away from the practical application of such methods. Other published methods used more common instrumentation but still required specialized equipment (43), involved solid-phase extraction (SPE), which used large volumes of solvents (44), or analyzed few compounds from the drug class (45,46) and therefore required separate procedures if multiple benzodiazepines were involved in a particular case analysis.…”

Section: Introductionmentioning

confidence: 99%

Quantitation of Benzodiazepines in Whole Blood by Electron Impact-Gas Chromatography-Mass Spectrometry

Tiscione

Shan

Alford

et al. 2008

Journal of Analytical Toxicology

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Benzodiazepines are frequently encountered in forensic toxicology. A literature search was conducted to find a simple method using electron impact-gas chromatography-mass spectrometry (EI-GC-MS) to examine whole blood specimens for the most commonly encountered benzodiazepines in the United States. A recently published method was identified in the literature search and used as a starting point for development of a new procedure to be used for routine analysis of forensic toxicology case samples. The procedure was then developed and validated as a rapid and efficient method for the screening and quantitation of benzodiazepines in blood using liquid-liquid extraction and EI-GC-MS in selective ion monitoring mode. Materials and instrumentation common to most forensic toxicology laboratories were utilized while obtaining LODs from 5 to 50 ng/mL and LOQs of 50 ng/mL or less using 1 mL of sample. Target compounds were chosen based on availability and common use in the United States and include diazepam, desalkylflurazepam, nordiazepam, midazolam, oxazepam, temazepam, lorazepam, clonazepam, and alprazolam (relative elution order). The linear range (r2 > 0.990) was validated from 50 to 1000 ng/mL for all analytes. The CV of replicate analyses at both 50 and 200 ng/mL was less than 4%. Quantitative accuracy was within +/- 16% at 50 ng/mL and within +/- 7% at 200 ng/mL. The validated method provides an efficient procedure for the quantitation of a broad range of the most common benzodiazepines in blood at meaningful limits of detection and quantitation using standard laboratory equipment and a small amount of sample.

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Extraction and analysis of clonazepam and 7-aminoclonazepam in whole blood using a dual internal standard methodology

Cited by 10 publications

References 12 publications

Mixed‐mode SPE for a multi‐residue analysis of benzodiazepines in whole blood using rapid GC with negative‐ion chemical ionization MS

Mixed‐mode SPE for a multi‐residue analysis of benzodiazepines in whole blood using rapid GC with negative‐ion chemical ionization MS

Surfactant-assisted dispersive liquid-liquid microextraction of nitrazepam and lorazepam from plasma and urine samples followed by high-performance liquid chromatography with UV analysis

Quantitation of Benzodiazepines in Whole Blood by Electron Impact-Gas Chromatography-Mass Spectrometry

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