Detection of mefenamic acid (M, non-steroidal anti-inflammatory drug, NSAIDs) and its metallodrug was investi- gated using electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. ESI-MS data (500 µL, 1×10-3 M) revealed high detection sensitivity for the drug and metallodrug. ESI-MS spectra revealed peaks at 242, 580, and 777 Da cor- responding to (M+H)+, (63Cu(M-H)2(H2O)2+H)+, and (56Fe(M-H)3+H)+, respectively. The metal:mefenamic ratios of ESI- MS spectra are in complete agreement with the fluorescence spectroscopy results (1:2 for Cu(II) and 1:3 for Fe(III)). ESI is a soft ionization technique that can be used on labile metallo-mefenamic acids and is promising for the detection of these species in environmental samples and biological fluids.
{"title":"Soft Ionization of Metallo-Mefenamic Using Electrospray Ionization Mass Spectrometry","authors":"H. Abdelhamid, Hui-Fen Wu","doi":"10.5478/MSL.2015.6.2.43","DOIUrl":"https://doi.org/10.5478/MSL.2015.6.2.43","url":null,"abstract":"Detection of mefenamic acid (M, non-steroidal anti-inflammatory drug, NSAIDs) and its metallodrug was investi- gated using electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. ESI-MS data (500 µL, 1×10-3 M) revealed high detection sensitivity for the drug and metallodrug. ESI-MS spectra revealed peaks at 242, 580, and 777 Da cor- responding to (M+H)+, (63Cu(M-H)2(H2O)2+H)+, and (56Fe(M-H)3+H)+, respectively. The metal:mefenamic ratios of ESI- MS spectra are in complete agreement with the fluorescence spectroscopy results (1:2 for Cu(II) and 1:3 for Fe(III)). ESI is a soft ionization technique that can be used on labile metallo-mefenamic acids and is promising for the detection of these species in environmental samples and biological fluids.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2015-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75727845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Choong Sik Lee, Soojin Park, Jae Young Lee, Sungsu Park, K. Jo, H. Oh
Abstract : In the present study, we proposed a simple ESI-MS model for determining Zn 2+ binding (or dissociation) constants forzinc finger peptides (ZFPs) with a unique ββα fold consensus. The ionization efficiency (response) factors for this model, i.e., α andβ, could be determined for ZiCo ZFP with a known Zn 2+ binding constant. We could determine the binding constants for other ZFPsassuming those with a ββα consensus conformation have the same α/β response ratio. In general, the ZPF dissociation constantsexhibited K d values of 10 -7 ~10 -9 M, while K d values for a negative control non-specific Zn 2+ peptides were high, e.g., 5.5 ×10 -6 M and4.3×10 -4 M for BBA1 and melittin, respectively.Key words : zinc finger, binding constant, electrospray-mass spectrometry, zinc ion Introduction Since its discovery in transcription factor IIIA (TFIIIA)from Xenopuslaevis, zinc finger proteins (ZFPs) have beenextensively researched due to their implications foreukaryotic protein-nucleic acid interactions.
{"title":"Mass Spectrometric Determination of Zn 2+ Binding/Dissociation Constant for Zinc Finger Peptides","authors":"Choong Sik Lee, Soojin Park, Jae Young Lee, Sungsu Park, K. Jo, H. Oh","doi":"10.5478/MSL.2015.6.1.7","DOIUrl":"https://doi.org/10.5478/MSL.2015.6.1.7","url":null,"abstract":"Abstract : In the present study, we proposed a simple ESI-MS model for determining Zn 2+ binding (or dissociation) constants forzinc finger peptides (ZFPs) with a unique ββα fold consensus. The ionization efficiency (response) factors for this model, i.e., α andβ, could be determined for ZiCo ZFP with a known Zn 2+ binding constant. We could determine the binding constants for other ZFPsassuming those with a ββα consensus conformation have the same α/β response ratio. In general, the ZPF dissociation constantsexhibited K d values of 10 -7 ~10 -9 M, while K d values for a negative control non-specific Zn 2+ peptides were high, e.g., 5.5 ×10 -6 M and4.3×10 -4 M for BBA1 and melittin, respectively.Key words : zinc finger, binding constant, electrospray-mass spectrometry, zinc ion Introduction Since its discovery in transcription factor IIIA (TFIIIA)from Xenopuslaevis, zinc finger proteins (ZFPs) have beenextensively researched due to their implications foreukaryotic protein-nucleic acid interactions.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2015-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84438963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yanxuan Fan, Yan Zhang, Qiaodi Jia, Jie Cao, Wenjie Wu
This study demonstrated the stabilizing role of a cyclodextrin on Keggin (PW12O40) 3- via hydrogen bonding complex- ation unveiled by ESI-MS. The distinctive fragmentation pathways of the {PW12}/γ-CD complexes from that of discrete (PW12O40) 3- showed that the so-called "weak" non-covalent interactions can effectively change the dissociation chemistry of POM in the gas phase. The influence of different types of solvents and organic additives such as γ-CD on the stability of Keggin (PW12O40) 3- was also addressed firstly by ESI-MS.
{"title":"The Stabilizing Role of Cyclodextrins on Keggin Phosphotungstic Acid by Complexation Unveiled by Electrospray Mass Spectrometry","authors":"Yanxuan Fan, Yan Zhang, Qiaodi Jia, Jie Cao, Wenjie Wu","doi":"10.5478/MSL.2015.6.1.13","DOIUrl":"https://doi.org/10.5478/MSL.2015.6.1.13","url":null,"abstract":"This study demonstrated the stabilizing role of a cyclodextrin on Keggin (PW12O40) 3- via hydrogen bonding complex- ation unveiled by ESI-MS. The distinctive fragmentation pathways of the {PW12}/γ-CD complexes from that of discrete (PW12O40) 3- showed that the so-called \"weak\" non-covalent interactions can effectively change the dissociation chemistry of POM in the gas phase. The influence of different types of solvents and organic additives such as γ-CD on the stability of Keggin (PW12O40) 3- was also addressed firstly by ESI-MS.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2015-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83940829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sesamin, one of the lignans in sesame seed, was a labile compound in MS and it was reported that the protonated mol- ecule of sesamin decomposed easily in ES ionization process and it cannot be detected (G. Yan, et al., Rapid Commun Mass Spectrom. 2007, 21, 3613-3620). To protect labile compounds, an amino-cyclodextrin (NCyD) was added to the sample to pro- mote the host-guest interaction complex in ESI-MS. As a result, sesamin was ionized as the NCyD-sesamin-NCyD (1:2) com- plex without undesired decomposition, suggesting that the amino-CyDs assist the ionization of the labile molecules capped with CyDs by host-guest interaction and these compounds were ionized without their decomposition, those are like amino-CyD com- plex-assisted ionization. The amino-CyD complexes of sesamin and sesamolin were also analyzed by their ion-mobility MS.
芝麻素是芝麻中的一种木脂素，在质谱中是一种不稳定的化合物，据报道，芝麻素的质子化分子在质谱电离过程中容易分解，不能被检测到(G. Yan, et al.， Rapid共质谱，2007,21,3613-3620)。为了保护不稳定的化合物，在ESI-MS中加入了氨基环糊精(NCyD)来促进主-客体相互作用复合物。结果表明，芝麻素被电离成ncyd -芝麻素- ncyd(1:2)复合物而没有发生分解，这表明氨基- cyd通过主-客体相互作用帮助带有cyd的不稳定分子电离，这些化合物被电离而没有分解，这些化合物类似于氨基- cyd复合物辅助电离。并用离子迁移率质谱分析了芝麻素和芝麻素的氨基- cyd复合物。
{"title":"Amino-β-cyclodextrin Complex Assisted Ionization for Labile Sesamins and their Ion-mobility Separation in ESI Q-TOF MS","authors":"Kohtaro Sugahara, M. Horikawa, T. Yamagaki","doi":"10.5478/MSL.2015.6.1.17","DOIUrl":"https://doi.org/10.5478/MSL.2015.6.1.17","url":null,"abstract":"Sesamin, one of the lignans in sesame seed, was a labile compound in MS and it was reported that the protonated mol- ecule of sesamin decomposed easily in ES ionization process and it cannot be detected (G. Yan, et al., Rapid Commun Mass Spectrom. 2007, 21, 3613-3620). To protect labile compounds, an amino-cyclodextrin (NCyD) was added to the sample to pro- mote the host-guest interaction complex in ESI-MS. As a result, sesamin was ionized as the NCyD-sesamin-NCyD (1:2) com- plex without undesired decomposition, suggesting that the amino-CyDs assist the ionization of the labile molecules capped with CyDs by host-guest interaction and these compounds were ionized without their decomposition, those are like amino-CyD com- plex-assisted ionization. The amino-CyD complexes of sesamin and sesamolin were also analyzed by their ion-mobility MS.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2015-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84623836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Characterizations of Two-step Matrix Application Procedures for Imaging Mass Spectrometry","authors":"S. Shimma","doi":"10.5478/MSL.2015.6.1.21","DOIUrl":"https://doi.org/10.5478/MSL.2015.6.1.21","url":null,"abstract":"","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2015-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77648692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xianjiang Li, Xin Wang, Linnan Li, Yu Bai, Huwei Liu
Direct analysis in real time mass spectrometry (DART-MS) is one of the variants of ambient mass spectrometry. The ionization process of DART-MS is in open environment and only takes few seconds, so it is suitable for fast analysis. Actually, since its introduction in 2005, more and more attentions have been drawn to its various applications due to its excellent proper- ties, e.g., fast analysis, and no or less sample preparation, high salt tolerance and so on. This review summarized the promising features of DART-MS, including its ionization mechanism, equipment modification, wide applications, coupling techniques and extraction strategies before analysis.
{"title":"Direct Analysis in Real Time Mass Spectrometry: a Powerful Tool for Fast Analysis","authors":"Xianjiang Li, Xin Wang, Linnan Li, Yu Bai, Huwei Liu","doi":"10.5478/MSL.2015.6.1.1","DOIUrl":"https://doi.org/10.5478/MSL.2015.6.1.1","url":null,"abstract":"Direct analysis in real time mass spectrometry (DART-MS) is one of the variants of ambient mass spectrometry. The ionization process of DART-MS is in open environment and only takes few seconds, so it is suitable for fast analysis. Actually, since its introduction in 2005, more and more attentions have been drawn to its various applications due to its excellent proper- ties, e.g., fast analysis, and no or less sample preparation, high salt tolerance and so on. This review summarized the promising features of DART-MS, including its ionization mechanism, equipment modification, wide applications, coupling techniques and extraction strategies before analysis.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2015-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83045316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-30DOI: 10.5478/MSL.2014.5.4.110
A. Somboro, D. Tiwari, A. Shobo, L. Bester, H. G. Kruger, T. Govender, S. Essack
The method of direct mass spectrometry profiling is reliable and reproducible for the rapid identification of clinical isolates of bacteria and fungi. This is the first study evaluating the approach of MALDI-TOF mass spectrometry profiling for rapid identification of carbapenemase-resistant enterobacteriaceae (CRE). Proof of concept was achieved by the discrimination of CRE using MALDI Biotyper MS based on the protein. This profiling appears promising by the visual observation of consist- ent unique peaks, albeit low intensity, that could be picked up from the mean spectra (MSP) method. The Biotyper MSP creation and identification methods needed to be optimized to provide significantly improved differences in scores to allow for subspe- cies identification with and without carbapenemases. These spectra were subjected to visual peak picking and in all cases; there were pertinent differences in the presence or absence of potential biomarker peaks to differentiate isolates. We also evaluated this method for potential discrimination between different carbapenemases bacteria, utilizing the same strategy. Based on our data and pending further investigation in other CREs, MALDI-TOF MS has potential as a diagnostic tool for the rapid identification of even closely related carbapenemases but would require a paradigm shift in which Biotyper suppliers enable more flexible software control of mass spectral profiling methods.
{"title":"Evaluation of MALDI Biotyping for Rapid Subspecies Identification of Carbapenemase-Producing Bacteria via Protein Profiling","authors":"A. Somboro, D. Tiwari, A. Shobo, L. Bester, H. G. Kruger, T. Govender, S. Essack","doi":"10.5478/MSL.2014.5.4.110","DOIUrl":"https://doi.org/10.5478/MSL.2014.5.4.110","url":null,"abstract":"The method of direct mass spectrometry profiling is reliable and reproducible for the rapid identification of clinical isolates of bacteria and fungi. This is the first study evaluating the approach of MALDI-TOF mass spectrometry profiling for rapid identification of carbapenemase-resistant enterobacteriaceae (CRE). Proof of concept was achieved by the discrimination of CRE using MALDI Biotyper MS based on the protein. This profiling appears promising by the visual observation of consist- ent unique peaks, albeit low intensity, that could be picked up from the mean spectra (MSP) method. The Biotyper MSP creation and identification methods needed to be optimized to provide significantly improved differences in scores to allow for subspe- cies identification with and without carbapenemases. These spectra were subjected to visual peak picking and in all cases; there were pertinent differences in the presence or absence of potential biomarker peaks to differentiate isolates. We also evaluated this method for potential discrimination between different carbapenemases bacteria, utilizing the same strategy. Based on our data and pending further investigation in other CREs, MALDI-TOF MS has potential as a diagnostic tool for the rapid identification of even closely related carbapenemases but would require a paradigm shift in which Biotyper suppliers enable more flexible software control of mass spectral profiling methods.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86509689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-30DOI: 10.5478/MSL.2014.5.4.115
B. R. Lima, F. Silva, H. H. F. Koolen, R. A. Almeida, A. D. L. Souza
The Brazil nut (Bertholletia excelsa - Lecythidaceae) is considered a product with high economic value, being a food widely appreciated for its nutritional qualities. Although previous studies have reported the biochemical composition of Brazil nut oil, the knowledge regarding the phospholipid composition exhibits a disagreement: the composition of fatty acids present in the structures of phospholipids is reported as being different from the composition of the free fatty acids present in the oil. In this work, solid phase extraction (SPE) was employed to provide a fast extraction of the phospholipids from Brazil nuts, in order to compare the phospholipid profile of the in nature nuts and their fatty acids precursor present in the oil. The major phospholipids were characterized by mass spectrometry approach. Their fragmentation pattern through direct infusion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MS 2 ) proved to be useful to unequivocal characterization of these substances. High resolution (HR) experiments through ESI using a quadruple time of flight mass spectrometry (QTOF) system were performed to reinforce the identifications.
{"title":"Solid Phase Extraction of Phospholipids from Brazil Nut (Bertholletia excelsa) and Their Characterization by Mass Spectrometry Analysis","authors":"B. R. Lima, F. Silva, H. H. F. Koolen, R. A. Almeida, A. D. L. Souza","doi":"10.5478/MSL.2014.5.4.115","DOIUrl":"https://doi.org/10.5478/MSL.2014.5.4.115","url":null,"abstract":"The Brazil nut (Bertholletia excelsa - Lecythidaceae) is considered a product with high economic value, being a food widely appreciated for its nutritional qualities. Although previous studies have reported the biochemical composition of Brazil nut oil, the knowledge regarding the phospholipid composition exhibits a disagreement: the composition of fatty acids present in the structures of phospholipids is reported as being different from the composition of the free fatty acids present in the oil. In this work, solid phase extraction (SPE) was employed to provide a fast extraction of the phospholipids from Brazil nuts, in order to compare the phospholipid profile of the in nature nuts and their fatty acids precursor present in the oil. The major phospholipids were characterized by mass spectrometry approach. Their fragmentation pattern through direct infusion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MS 2 ) proved to be useful to unequivocal characterization of these substances. High resolution (HR) experiments through ESI using a quadruple time of flight mass spectrometry (QTOF) system were performed to reinforce the identifications.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78062881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-30DOI: 10.5478/MSL.2014.5.4.120
Jong-Ho Park
The interference of water vapor on the chemical ionization (CI) of hydroxyl radicals (OH) by sulfur hexafluoride ion (SF6 - ) was investigated using a flow tube system coupled to a high-pressure CI mass spectrometer. Water vapor, which is required to study heterogeneous reactions of OH under real tropospheric conditions, transforms the reagent ion SF6 - into SF4O - and F - (HF)n, resulting in a substantial loss in CI sensitivity. Therefore, under humid conditions, peaks corresponding to OH are drastically diminished, while those corresponding to OH-water complex ions ((OH(H2O)n) - ) are enhanced. (OH(H2O)3) - was observed as the major OH species. The obsercation of (OH(H2O)n) - by isolating humid conditions to the CI region and prelimi- nary ab initio calculations suggested that (OH(H2O)n) - ions were produced from reactions between OH ions (OH - ) and water molecules. An additional helium buffer flow introduced into the CI region reduced loss of the reagent ion and resulted in a par- tial recovery of OH peak intensities under humid conditions.
{"title":"Experimental Study on the Interference of Water Vapor on the Chemical Ionization of OH by Sulfur Hexafluoride Ion","authors":"Jong-Ho Park","doi":"10.5478/MSL.2014.5.4.120","DOIUrl":"https://doi.org/10.5478/MSL.2014.5.4.120","url":null,"abstract":"The interference of water vapor on the chemical ionization (CI) of hydroxyl radicals (OH) by sulfur hexafluoride ion (SF6 - ) was investigated using a flow tube system coupled to a high-pressure CI mass spectrometer. Water vapor, which is required to study heterogeneous reactions of OH under real tropospheric conditions, transforms the reagent ion SF6 - into SF4O - and F - (HF)n, resulting in a substantial loss in CI sensitivity. Therefore, under humid conditions, peaks corresponding to OH are drastically diminished, while those corresponding to OH-water complex ions ((OH(H2O)n) - ) are enhanced. (OH(H2O)3) - was observed as the major OH species. The obsercation of (OH(H2O)n) - by isolating humid conditions to the CI region and prelimi- nary ab initio calculations suggested that (OH(H2O)n) - ions were produced from reactions between OH ions (OH - ) and water molecules. An additional helium buffer flow introduced into the CI region reduced loss of the reagent ion and resulted in a par- tial recovery of OH peak intensities under humid conditions.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83989132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-30DOI: 10.5478/MSL.2014.5.4.104
Woonyong Kwon, Sungill Suh, M. In, Jin Young Kim
Nonmedical use of prescription stimulants such as methylphenidate (MPH) and amphetamine (AP) by normal per- sons has been increased to improve cognitive functions. Due to high potential for their abuse, reliable analytical methods were required to detect these prescription stimulants in biological samples. A direct injection liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and implemented for simultaneous determination of MPH, AP and their metabolites ritalinic acid (RA) and 4-hydroxyamphetamine (HAP) in human urine. Urine sample was centrifuged and the upper layer (100 µL) was mixed with 800 µL of distilled water and 100 µL of internal standards (0.2 µg/mL in methanol). The mixture was then directly injected into the LC-MS/MS system. The mobile phase was composed of 0.2% formic acid in distilled water (A) and acetonitrile (B). Chromatographic separation was performed by using a Capcell Pak MG-II C18 (150 mm × 2.0 mm i.d., 5 µm, Shiseido) column and all analytes were eluted within 5 min. Linear least-squares regression with a 1/x weighting factor was used to generate a calibration curve and the assay was linear from 20 to 1500 ng/mL (HAP), 40-3000 ng/mL (AP and RA) and 2-150 ng/mL (MPH). The intra- and inter-day precisions were within 16.4%. The intra- and inter-day accuracies ranged from -15.6% to 10.8%. The limits of detection for all the analytes were less than 4.7 ng/mL. The suitability of the method was examined by analyzing urine samples from drug abusers.
正常人非医疗使用处方兴奋剂，如哌甲酯(MPH)和安非他明(AP)，以改善认知功能。由于其滥用的可能性很大，因此需要可靠的分析方法来检测生物样品中的这些处方兴奋剂。建立了直接进样液相色谱-串联质谱(LC-MS/MS)同时测定人尿中MPH、AP及其代谢物利他酸(RA)和4-羟安非他明(HAP)的方法。尿样离心后，上层(100µL)与800µL蒸馏水和100µL内标(0.2µg/mL甲醇)混合。然后将混合物直接注入LC-MS/MS系统。流动相组成的0.2%甲酸在蒸馏水(A)和乙腈(B)。色谱分离是由使用Capcell Pak MG-II C18(150毫米×2.0毫米身份证。5µm,资生堂)列和所有分析物中筛选了5分钟。线性最小二乘回归与1 / x权重因子用于生成校准曲线,分析线性从20到1500 ng / mL (HAP), 40 - 3000 ng / mL(美联社和RA)和2 - 150 ng / mL(英里/小时)。日内、日间精度均在16.4%以内。日内和日间的准确度在-15.6%至10.8%之间。所有分析物的检出限均小于4.7 ng/mL。通过对吸毒者尿样的分析，检验了该方法的适用性。
{"title":"Simultaneous Determination of Methylphenidate, Amphetamine and their Metabolites in Urine using Direct Injection Liquid Chromatography-Tandem Mass Spectrometry","authors":"Woonyong Kwon, Sungill Suh, M. In, Jin Young Kim","doi":"10.5478/MSL.2014.5.4.104","DOIUrl":"https://doi.org/10.5478/MSL.2014.5.4.104","url":null,"abstract":"Nonmedical use of prescription stimulants such as methylphenidate (MPH) and amphetamine (AP) by normal per- sons has been increased to improve cognitive functions. Due to high potential for their abuse, reliable analytical methods were required to detect these prescription stimulants in biological samples. A direct injection liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and implemented for simultaneous determination of MPH, AP and their metabolites ritalinic acid (RA) and 4-hydroxyamphetamine (HAP) in human urine. Urine sample was centrifuged and the upper layer (100 µL) was mixed with 800 µL of distilled water and 100 µL of internal standards (0.2 µg/mL in methanol). The mixture was then directly injected into the LC-MS/MS system. The mobile phase was composed of 0.2% formic acid in distilled water (A) and acetonitrile (B). Chromatographic separation was performed by using a Capcell Pak MG-II C18 (150 mm × 2.0 mm i.d., 5 µm, Shiseido) column and all analytes were eluted within 5 min. Linear least-squares regression with a 1/x weighting factor was used to generate a calibration curve and the assay was linear from 20 to 1500 ng/mL (HAP), 40-3000 ng/mL (AP and RA) and 2-150 ng/mL (MPH). The intra- and inter-day precisions were within 16.4%. The intra- and inter-day accuracies ranged from -15.6% to 10.8%. The limits of detection for all the analytes were less than 4.7 ng/mL. The suitability of the method was examined by analyzing urine samples from drug abusers.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84579471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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