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B K Matuszewski - One of the best experts on this subject based on the ideXlab platform.
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standard line slopes as a measure of a relative Matrix Effect in quantitative hplc ms bioanalysis
Journal of Chromatography B, 2006Co-Authors: B K MatuszewskiAbstract:A simple experimental approach for studying and identifying the relative Matrix Effect (for example "plasma-to-plasma" and/or "urine-to-urine") in quantitative analyses by HPLC-MS/MS is described. Using as a database a large number of examples of methods developed in recent years in our laboratories, the relationship between the precision of standard line slopes constructed in five different lots of a biofluid (for example plasma) and the reliability of determination of concentration of an analyte in a particular plasma lot (or subject) was examined. In addition, the precision of standard line slopes was compared when stable isotope-labeled analytes versus analogs were used as internal standards (IS). Also, in some cases, a direct comparison of standard line slopes was made when different HPLC-MS interfaces (APCI versus ESI) were used for the assay of the same compound, using the same IS and the same sample preparation and chromatographic separation conditions. In selected cases, the precision of standard line slopes in five different lots of a biofluid was compared with precision values determined five times in a single lot. The results of these studies indicated that the variability of standard line slopes in different lots of a biofluid [precision of standard line slopes expressed as coefficient of variation, CV (%)] may serve as a good indicator of a relative Matrix Effect and, it is suggested, this precision value should not exceed 3-4% for the method to be considered reliable and free from the relative Matrix Effect liability. Based on the results presented, in order to assess the relative Matrix Effect in bioanalytical methods, it is recommended to perform assay precision and accuracy determination in five different lots of a biofluid, instead of repeat (n=5) analysis in the same, single biofluid lot, calculate standard line slopes and precision of these slopes, and to use <3-4% slope precision value as a guide for method applicability to support clinical studies. It was also demonstrated that when stable isotope-labeled analytes were used as internal standards, the precision of standard line slopes in five different lots of a biofluid was Matrix Effect. Also, the utilization of the APCI interface instead of ESI led to the elimination of the relative Matrix Effect in all cases studied. When the precision of standard line slope values exceeds the 3-4% limit, the method may require improvements (a more efficient chromatography, a more selective extraction, a stable isotope-labeled IS instead of an analog as an IS, and/or a change in the HPLC-MS interface) to eliminate the relative Matrix Effect and to improve assay selectivity.
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Standard line slopes as a measure of a relative Matrix Effect in quantitative HPLC–MS bioanalysis
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2005Co-Authors: B K MatuszewskiAbstract:A simple experimental approach for studying and identifying the relative Matrix Effect (for example "plasma-to-plasma" and/or "urine-to-urine") in quantitative analyses by HPLC-MS/MS is described. Using as a database a large number of examples of methods developed in recent years in our laboratories, the relationship between the precision of standard line slopes constructed in five different lots of a biofluid (for example plasma) and the reliability of determination of concentration of an analyte in a particular plasma lot (or subject) was examined. In addition, the precision of standard line slopes was compared when stable isotope-labeled analytes versus analogs were used as internal standards (IS). Also, in some cases, a direct comparison of standard line slopes was made when different HPLC-MS interfaces (APCI versus ESI) were used for the assay of the same compound, using the same IS and the same sample preparation and chromatographic separation conditions. In selected cases, the precision of standard line slopes in five different lots of a biofluid was compared with precision values determined five times in a single lot. The results of these studies indicated that the variability of standard line slopes in different lots of a biofluid [precision of standard line slopes expressed as coefficient of variation, CV (%)] may serve as a good indicator of a relative Matrix Effect and, it is suggested, this precision value should not exceed 3-4% for the method to be considered reliable and free from the relative Matrix Effect liability. Based on the results presented, in order to assess the relative Matrix Effect in bioanalytical methods, it is recommended to perform assay precision and accuracy determination in five different lots of a biofluid, instead of repeat (n=5) analysis in the same, single biofluid lot, calculate standard line slopes and precision of these slopes, and to use
Johann Michler - One of the best experts on this subject based on the ideXlab platform.
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The Matrix Effect in TOF-SIMS analysis of two-element inorganic thin films
Journal of Analytical Atomic Spectrometry, 2020Co-Authors: Agnieszka Priebe, Tianle Xie, Gerhard Bürki, Laszlo Pethö, Johann MichlerAbstract:The Matrix Effect, i.e. the dependence of element ion yield on the surrounding chemical state, is very often considered as a negative and limiting factor in elemental characterization. In fact, it is the main reason making Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) a non-quantitative technique as element ionization efficiency can span over several orders of magnitude depending on the Matrix. Despite that, even small chemical variations of an experimental setup can cause interpretation of TOF-SIMS depth profiles a challenging task. However, the sensitivity of element ionization to the neighboring atoms can also be very beneficial as ion yields can be enhanced in the presence of particular species such as oxygen, cesium, water and fluorine. In this work, we make an attempt to estimate the Matrix Effect in two-element Zr-containing alloys using TOF-SIMS. The Zr ionization efficiency as well as its response to the surface and interface contaminants was investigated depending on Al, Si and Cu matrices. It was observed that Zr ionization efficiency is over four times higher in the Si Matrix than in the Cu Matrix and over two times higher when compared to the results obtained in the Al Matrix.
Yuehui Kang - One of the best experts on this subject based on the ideXlab platform.
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Matrix Effect in high-performance liquid chromatography-tandem mass spectrometry analysis of antibiotics in environmental water samples.
Journal of separation science, 2013Co-Authors: Jun Liang Zhou, Yuehui KangAbstract:This paper describes the Matrix Effect during the analysis of ten antibiotic compounds in water by SPE followed by HPLC-ESI-MS/MS. The target analytes were tetracycline, oxytetracycline (tetracyclines), sulfathiazole, sulfamethazine, sulfadiazine (sulfonamides), erythromycin-H2O, roxithromycine, spiramycin (macrolides), ofloxacin, and norfloxacin (quinolones). The Matrix Effect was examined for internal standards and the target analytes in five different water Matrixes, with signal suppression being increased in the order: ultrapure water, tap water, river water, sewage effluent, and sewage influent. A combined application of the internal standards and Matrix-matched extract calibration was shown to be successful in compensating the Matrix Effect for the analytes. The procedural recovery of the target compounds in sewage effluents and influents was higher than in river water samples, which was further enhanced by sample acidification to pH 2. The validity of the internal standard based Matrix-matched calibration approach was verified by the standard addition method.
Hajime Nishio - One of the best experts on this subject based on the ideXlab platform.
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Determination of acephate and methamidophos in tissues: appearance of Matrix Effect in gas chromatography–mass spectrometry
Forensic Toxicology, 2011Co-Authors: Nobuyuki Adachi, Hiroshi Kinoshita, Minori Nishiguchi, Motonori Takahashi, Harumi Ouchi, Takako Minami, Kiyoshi Matsui, Takehiko Yamamura, Shie Yoshida, Hajime NishioAbstract:A simple and reliable method to determine acephate and methamidophos in mammalian tissues is presented. The method includes solid-phase extraction of tissue extracts with active carbon cartridges followed by gas chromatography–mass spectrometry analysis. During the study, a Matrix Effect was observed especially at low concentrations of acephate and methamidophos in serum and in brain. To minimize the Effect, we prepared calibration curves with relatively short ranges. The validation data, such as the linearity of calibration curves, limits of detection, and coefficients of variation for recovery rates, were generally satisfactory. The present method is useful for determination of acephate and methamidophos in mammalian tissues because of its simplicity and speed, keeping in mind the presence of the Matrix Effect.
Hong-chen Hao - One of the best experts on this subject based on the ideXlab platform.
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Matrix Effect on the photoluminescence of Si nanocrystal
Journal of Nanoparticle Research, 2012Co-Authors: Jiang Zhu, Hong-chen HaoAbstract:To examine the Matrix Effect on the light emission of Si nanocrystal (Si-NC), we investigated the photoluminescence (PL) of Si-NC from multilayered samples of Si/SiO2 and SiO/SiO2 and single-layered pure Si thin films, which had all been annealed in nitrogen at 1,100 °C for 1 h so as to form Si-NCs. The size range of Si-NC is 1–10 nm. It was found that the density of Si-NC in the pure Si> that in Si/SiO2> that in SiO/SiO2, but the PL intensity of Si-NC from pure Si< that from Si/SiO2< that from SiO/SiO2. On the other hand, the PL intensity of Si-NC from Si/SiO2 sample is higher than that from Si/Si3N4 one. All these results are related to the difference in Matrix surrounding Si-NCs, which causes differences in carrier confinement or/and interface state. The results suggest that for light emission of Si-NC, the Matrix Effect is determinative, and can be more important than the density of Si-NC itself.