Trends in quality in the analytical laboratory. II. Analytical method validation and quality assurance

Taverniers, Isabel; Loose, Marc De; Bockstaele, Erik Van

doi:10.1016/j.trac.2004.04.001

Cited by 772 publications

(501 citation statements)

References 36 publications

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“…Each analyte exhibited good linearity with correlation coefficient (r 2 ) > 0.99 in the studied range. The limits of detection, calculated on the basis of signalto-noise ratio of 3 (S/N = 3) [45] ranged between 0.12 and 0.17 g/L. The precision of analytical method was investigated using six replicate experiments with 300 mL standard solution containing each the PAEs 1.0 g/L, and the relative standard deviation (R.S.D.)…”

Section: Analytical Performancementioning

confidence: 99%

Analysis of phthalates via HPLC-UV in environmental water samples after concentration by solid-phase extraction using ionic liquid mixed hemimicelles

Cai

Shi

et al. 2008

Talanta

154

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Ionic liquid mixed hemimicelles-based solid-phase extraction for the preconcentration of five phthalates in environmental water sample was investigated in this paper. A comparative study on the use of room temperature ionic liquids (RTILs) 1-hexyl-3-methylimidazolium bromide ([C 6 mim]Br) and 1-dodecyl-3-methylimidazolium bromide ([C 12 mim]Br)-coated silica as sorbents was presented. Owing to having bigger adsorption amounts for analytes [C 12 mim], Br-coated silica was selected as SPE material and the five analytes di-ethyl-phthalate (DEP), di-n-propyl-phthalate (DnPP), di-n-butyl-phthalate (DnBP), di-cyclohexyl-phthalate (DcHP) and di-(2-ethylhexyl)-phthalate (DEHP) can be quantitatively extracted under optimal conditions. The analytes retained on the cartridge were desorbed completely with 3 mL methanol (pH 2). Predominant factors influencing the extraction efficiency, such as RTILs concentration, pH value, ionic strength and breakthrough volume were discussed. The proposed method had been applied to determining the five phthalates in four environmental water samples and concentration factor of 600 was achieved easily. Detection limits obtained ranged between 0.12 and 0.17 g/L. The accuracy of this method was evaluated by recovery measurement on spiked samples, and good recovery results (85-107%) with relative standard deviation (R.S.D.) of below 6% were achieved.

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Section: Analytical Performancementioning

confidence: 99%

Analysis of phthalates via HPLC-UV in environmental water samples after concentration by solid-phase extraction using ionic liquid mixed hemimicelles

Cai

Shi

et al. 2008

Talanta

154

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“…The limit of detection (LOD) was derived from the lowest measured signal (X L ), using the nonlinear fitting equation, with X L = X bl + 3S bl for which X bl is the mean of the blank measurement and S bl is the standard deviation of the blank measurement. 6 ■ RESULTS Selection of mLcn2 Aptamers. The SELEX procedure was performed for 10 rounds, after which the mLcn2 bound RNA was found to have been enriched to 18%, from the starting 0.4%, bound to the protein (see Figure 2A).…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

An RNA Aptamer-Based Microcantilever Sensor To Detect the Inflammatory Marker, Mouse Lipocalin-2

et al. 2012

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Lipocalin-2 (Lcn2) is a biomarker for many inflammatory-based diseases, including acute kidney injury, cardiovascular stress, diabetes, and various cancers. Inflammatory transitions occur rapidly in kidney and cardiovascular disease, for which an in-line monitor could be beneficial. Microcantilever devices with aptamers as recognition elements can be effective and rapidly responsive sensors. Here, we have selected and characterized an RNA aptamer that specifically binds mouse Lcn2 (mLcn2) with a dissociation constant of 340 ± 70 nM in solution and 38 ± 22 nM when immobilized on a surface. The higher apparent affinity of the immobilized aptamer may result from its effective multivalency that decreases the off-rate. The aptamer competes with a catechol iron-siderophore, the natural ligand of mLcn2. This and the results of studies with mLcn2 mutants demonstrate that the aptamer binds to the siderophore binding pocket of the protein. A differential interferometer-based microcantilever sensor was developed with the aptamer as the recognition element in which the differential response between two adjacent cantilevers (a sensing/reference pair) is utilized to detect the binding between mLcn2 and the aptamer, ensuring that sensor response is independent of environmental influences, distance between sensing surface and detector and nonspecific binding. The system showed a detection limit of 4 nM. This novel microcantilever aptasensor has potential for development as an in-line monitoring system for mLcn2 in studies of animal models of acute diseases such as kidney and cardiac failure. ABSTRACT: Lipocalin-2 (Lcn2) is a biomarker for many inflammatory-based diseases, including acute kidney injury, cardiovascular stress, diabetes, and various cancers. Inflammatory transitions occur rapidly in kidney and cardiovascular disease, for which an in-line monitor could be beneficial. Microcantilever devices with aptamers as recognition elements can be effective and rapidly responsive sensors. Here, we have selected and characterized an RNA aptamer that specifically binds mouse Lcn2 (mLcn2) with a dissociation constant of 340 ± 70 nM in solution and 38 ± 22 nM when immobilized on a surface. The higher apparent affinity of the immobilized aptamer may result from its effective multivalency that decreases the off-rate. The aptamer competes with a catechol iron-siderophore, the natural ligand of mLcn2. This and the results of studies with mLcn2 mutants demonstrate that the aptamer binds to the siderophore binding pocket of the protein. A differential interferometer-based microcantilever sensor was developed with the aptamer as the recognition element in which the differential response between two adjacent cantilevers (a sensing/reference pair) is utilized to detect the binding between mLcn2 and the aptamer, ensuring that sensor response is independent of environmental influences, distance between sensing surface and detector and nonspecific binding. The system showed a detection limit of 4 nM. This novel microcantilever aptasen...

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“…The limits of detection (LODs) and limits of quantification (LOQs) of the individual compounds were determined by calculating signal/noise ratio (S/N = 3) and (S/N = 10), respectively (Taverniers et al, 2004). The LODs were below 0.22 μg/g and the LOQ varied between 0.10 and 0.73 μg/g.…”

Section: Analytical Performance Characteristicsmentioning

confidence: 99%

Microwave‐assisted micellar extraction coupled with solid‐phase extraction for preconcentration of pharmaceuticals in molluscs prior to determination by HPLC

Cueva-Mestanza

Torres-Padrón

Sosa‐Ferrera

et al. 2008

Biomedical Chromatography

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A simple and specific analytical method was developed and tested for the determination of pharmaceuticals in mollusc samples. A combination of microwave-assisted micellar extraction (MAME) and solid-phase extraction (SPE) using a non-ionic surfactant, polyoxyethylene 10 lauryl ether, was examined to extract and determine simultaneously a group of pharmaceuticals such as carbamazepine, clorfibric acid, ketoprofen, naproxen, bezafibrate and ibuprofen by liquid chromatography using UV-diode array detector. The MAME extraction performance was evaluated by studying various parameters such as the volume and concentration of surfactant and microwave conditions. Finally, an OASIS HLB cartridge was used as an optimum SPE sorbent to clean up the extracts and preconcentrate the selected analytes. The proposed method showed satisfactory linearity and reproducibility (between 3 and 15%), as well as detection limits ranging from 30 to 220 ng/g. Finally, the method was successfully applied to the determination of the target pharmaceuticals in various kinds of mollusc samples. This study has demonstrated that microwave-assisted micellar extraction with solid-phase extraction may be used as a viable alternative to conventional methods for the extraction of pharmaceuticals in this type of matrices.

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Trends in quality in the analytical laboratory. II. Analytical method validation and quality assurance

Cited by 772 publications

References 36 publications

Analysis of phthalates via HPLC-UV in environmental water samples after concentration by solid-phase extraction using ionic liquid mixed hemimicelles

Analysis of phthalates via HPLC-UV in environmental water samples after concentration by solid-phase extraction using ionic liquid mixed hemimicelles

An RNA Aptamer-Based Microcantilever Sensor To Detect the Inflammatory Marker, Mouse Lipocalin-2

Microwave‐assisted micellar extraction coupled with solid‐phase extraction for preconcentration of pharmaceuticals in molluscs prior to determination by HPLC

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