We prepared solid dispersion formulations of quercetin to enhance its solubility and dissolution rate. Various quercetinloaded solid dispersion were tested with quercetin, poloxamer 407, and carrier such as hydroxypropyl methyl cellulose (HPMC), polyethylene glycol 8000 (PEG 8000), and polyvinylpyrrolidone K40 (PVP K40) using solvent evaporation and freeze drying methods in terms of both the aqueous solubility and the dissolution rates of quercetin. The solubility of quercetin as its solid dispersion formulations was markedly improved compared with that of quercetin powder. Especially, highest solubility of quercetin was observed when HPMC was used as a carrier. The cumulative dissolution of quercetin within 360 min from solid dispersion composed of quercetin, poloxamer 407, and HPMC was 8.8-fold higher than the dissolution of pure quercetin. The results of powder Xray diffraction (XRD) and scanning electron microscope (SEM) indicated that quercetin transformed from a crystalline to an amorphous form through the solid dispersion formulation process. These results suggest that the solid dispersion formulation of quercetin with poloxamer 407 and HPMC could be a promising option for enhancing the solubility and dissolution rate of quercetin.
{"title":"Preparation and Characterization of Quercetin-Loaded Solid Dispersion by Solvent Evaporation and Freeze-Drying Method","authors":"S. H. Park, I. Song, Min‐Koo Choi","doi":"10.5478/MSL.2016.7.3.79","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.3.79","url":null,"abstract":"We prepared solid dispersion formulations of quercetin to enhance its solubility and dissolution rate. Various quercetinloaded solid dispersion were tested with quercetin, poloxamer 407, and carrier such as hydroxypropyl methyl cellulose (HPMC), polyethylene glycol 8000 (PEG 8000), and polyvinylpyrrolidone K40 (PVP K40) using solvent evaporation and freeze drying methods in terms of both the aqueous solubility and the dissolution rates of quercetin. The solubility of quercetin as its solid dispersion formulations was markedly improved compared with that of quercetin powder. Especially, highest solubility of quercetin was observed when HPMC was used as a carrier. The cumulative dissolution of quercetin within 360 min from solid dispersion composed of quercetin, poloxamer 407, and HPMC was 8.8-fold higher than the dissolution of pure quercetin. The results of powder Xray diffraction (XRD) and scanning electron microscope (SEM) indicated that quercetin transformed from a crystalline to an amorphous form through the solid dispersion formulation process. These results suggest that the solid dispersion formulation of quercetin with poloxamer 407 and HPMC could be a promising option for enhancing the solubility and dissolution rate of quercetin.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"16 1","pages":"79-83"},"PeriodicalIF":0.5,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73262985","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}
J. Jo, W. Nam, Sunjoo Kim, Doohyun Lee, K. Min, Taeho Lee, Sangkyu Lee
{"title":"Identification of ML106 Phase 1 Metabolites in Human Liver Microsomes Using High-Resolution Quadrupole-Orbitrap Mass Spectrometry","authors":"J. Jo, W. Nam, Sunjoo Kim, Doohyun Lee, K. Min, Taeho Lee, Sangkyu Lee","doi":"10.5478/MSL.2016.7.3.69","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.3.69","url":null,"abstract":"","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"6 1","pages":"69-73"},"PeriodicalIF":0.5,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74662058","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}
H. Min, Boyoung Han, Changmin Sung, K. Lee, H. Kim, Ki Hun Kim, J. Son, Jaeick Lee
Growth hormone (GH)-releasing peptides (GHRPs) and GH secretagogues (GHSs) are listed in the World Anti-Doping Agency (WADA) Prohibited List. In the present study, we developed and validated a method for the simultaneous analysis of seven GHRPs (alexamorelin, GHRP-1, -2, -4, -5, -6, and hexarelin) and three GHSs (anamorelin, ibutamoren, and ipamorelin) in human urine. Method validation was performed at minimum required performance levels specified by WADA technical documents (2 ng/mL) for all substances, and the method was validated with regard to selectivity (no interference), linearity (R2 > 0.9986), matrix effects (50.0%-141.2%), recovery (10.4%-100.8%), and intra- (2.8%-16.5%) and inter-day (7.0%-22.6%) precisions. The limits of detection for screening and confirmation were 0.05-0.5 ng/mL and 0.05-1 ng/mL, respectively.
{"title":"LC-MS/MS Method for Simultaneous Analysis of Growth Hormone-Releasing Peptides and Secretagogues in Human Urine","authors":"H. Min, Boyoung Han, Changmin Sung, K. Lee, H. Kim, Ki Hun Kim, J. Son, Jaeick Lee","doi":"10.5478/MSL.2016.7.3.55","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.3.55","url":null,"abstract":"Growth hormone (GH)-releasing peptides (GHRPs) and GH secretagogues (GHSs) are listed in the World Anti-Doping Agency (WADA) Prohibited List. In the present study, we developed and validated a method for the simultaneous analysis of seven GHRPs (alexamorelin, GHRP-1, -2, -4, -5, -6, and hexarelin) and three GHSs (anamorelin, ibutamoren, and ipamorelin) in human urine. Method validation was performed at minimum required performance levels specified by WADA technical documents (2 ng/mL) for all substances, and the method was validated with regard to selectivity (no interference), linearity (R2 > 0.9986), matrix effects (50.0%-141.2%), recovery (10.4%-100.8%), and intra- (2.8%-16.5%) and inter-day (7.0%-22.6%) precisions. The limits of detection for screening and confirmation were 0.05-0.5 ng/mL and 0.05-1 ng/mL, respectively.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"58 1","pages":"55-63"},"PeriodicalIF":0.5,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83576502","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}
Targeted glycoproteomics is an effective way to discover disease-associated glycoproteins in proteomics and serial affinity chromatography (SAC) using lectin and glycan-targeting antibodies shows glycan diversity on the captured glycoproteins. This study suggests a way to determine glycan heterogeneity and structural analysis on the post-translationally modified proteins through serial affinity column set (SACS) using four Lycopersicon esculentum lectin (LEL) columns. The great advantage of this method is that it differentiates between glycoproteins on the basis of their binding affinity. Through this study, some proteins were identified to have glycoforms with different affinity on a single glycoprotein. It will be particularly useful in determining biomarkers in which the disease-specific feature is a unique glycan, or a group of glycans.
{"title":"Differentiation of Glycan Diversity with Serial Affinity Column Set (SACS)","authors":"Jihoon Shin, W. Cho","doi":"10.5478/MSL.2016.7.3.74","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.3.74","url":null,"abstract":"Targeted glycoproteomics is an effective way to discover disease-associated glycoproteins in proteomics and serial affinity chromatography (SAC) using lectin and glycan-targeting antibodies shows glycan diversity on the captured glycoproteins. This study suggests a way to determine glycan heterogeneity and structural analysis on the post-translationally modified proteins through serial affinity column set (SACS) using four Lycopersicon esculentum lectin (LEL) columns. The great advantage of this method is that it differentiates between glycoproteins on the basis of their binding affinity. Through this study, some proteins were identified to have glycoforms with different affinity on a single glycoprotein. It will be particularly useful in determining biomarkers in which the disease-specific feature is a unique glycan, or a group of glycans.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"46 1","pages":"74-78"},"PeriodicalIF":0.5,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74171237","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}
: Scanning electron microscopy combined with thermal ionization mass spectrometry (SEM-TIMS) was used to determine the precise isotope ratios of ultra-trace levels of uranium contained in individual microparticles. An advanced multiple ion counter system consisting of three secondary ion multipliers and two compact discrete dynodes was used for complete simultaneous ion detection. For verification purposes, using TIMS with complete simultaneous measurement, isotopes were analyzed in 5 pg of uranium of a certified reference material. A microprobe in the SEM was used to transfer individual particles from a NUSIMEP-7 sample to TIMS filaments, which were then subjected to SEM-TIMS and complete simultaneous measurement. The excellent agreement in the resulting uranium isotope ratios with the certified NUSIMEP-7 values shows the validity of SEM-TIMS with complete simultaneous measurement for the analysis of uranium isotopes in individual particles. Further experimental study required for investigation of simultaneous measurement using the advanced multiple ion counter system is presented.
{"title":"Complete Simultaneous Analysis of Uranium Isotopes in NUSIMEP-7 Microparticles Using SEM-TIMS","authors":"Jong-Ho Park, Kahee Jeong","doi":"10.5478/MSL.2016.7.3.64","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.3.64","url":null,"abstract":": Scanning electron microscopy combined with thermal ionization mass spectrometry (SEM-TIMS) was used to determine the precise isotope ratios of ultra-trace levels of uranium contained in individual microparticles. An advanced multiple ion counter system consisting of three secondary ion multipliers and two compact discrete dynodes was used for complete simultaneous ion detection. For verification purposes, using TIMS with complete simultaneous measurement, isotopes were analyzed in 5 pg of uranium of a certified reference material. A microprobe in the SEM was used to transfer individual particles from a NUSIMEP-7 sample to TIMS filaments, which were then subjected to SEM-TIMS and complete simultaneous measurement. The excellent agreement in the resulting uranium isotope ratios with the certified NUSIMEP-7 values shows the validity of SEM-TIMS with complete simultaneous measurement for the analysis of uranium isotopes in individual particles. Further experimental study required for investigation of simultaneous measurement using the advanced multiple ion counter system is presented.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"218 1","pages":"64-68"},"PeriodicalIF":0.5,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87014370","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":"Recent Developments in Nuclear Forensic and Nuclear Safeguards Analysis Using Mass Spectrometry","authors":"K. Song, Jong-Ho Park, Chi-Gyu Lee, Sun-ho Han","doi":"10.5478/MSL.2016.7.2.31","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.2.31","url":null,"abstract":"","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"11 1","pages":"31-40"},"PeriodicalIF":0.5,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77251771","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}
An UHPLC-ESI-qTOF-MS analytical method was developed for cyclopeptide alkaloids in the seeds of Ziziphus jujuba var. spinosa (Semen Ziziphi Spinosae), which is a commonly used herb in Chinese and Korean traditional medicines. Considering the basicity of cyclopeptide alkaloids, a specific separation method was developed for an UHPLC system. The compounds were detected by DAD and ESI-qTOF-MS, and their fragmentation patterns were also acquired by MS^{E} technologies. Peak-picking of major compounds was performed with nine previously isolated compounds and two reference standard compounds. Tandem MS fragmentation behaviors of type-Ia and -Ib cyclopeptide alkaloids were investigated with the acquired data to develop a strategy for dereplication of other cyclopeptide alkaloid compounds in Z. jujuba var. spinosa. Two more cyclopeptide alkaloids were tentatively identified with UHPLC-ESI-qTOF-MS using this method.
建立了一种hplc - esi - qtof - ms分析方法，分析了中药材中药材枣仁中环肽生物碱的含量。考虑到环肽生物碱的碱性，建立了一种高效液相色谱分离环肽生物碱的方法。通过DAD和ESI-qTOF-MS对化合物进行了检测，并通过MS^{E}技术获得了化合物的断裂模式。对9个先前分离的化合物和2个标准化合物进行了主要化合物的选峰。利用获得的数据研究了- ia型和-Ib型环肽生物碱的串联质谱断裂行为，以建立其他环肽生物碱化合物在枣树中的分离策略。并用UHPLC-ESI-qTOF-MS对另外两种环肽生物碱进行了初步鉴定。
{"title":"UHPLC-ESI-qTOF-MS Analysis of Cyclopeptide Alkaloids in the Seeds of Ziziphus jujuba var. spinosa","authors":"K. Kang, D. Jang, Jinwoong Kim, S. Sung","doi":"10.5478/MSL.2016.7.2.45","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.2.45","url":null,"abstract":"An UHPLC-ESI-qTOF-MS analytical method was developed for cyclopeptide alkaloids in the seeds of Ziziphus jujuba var. spinosa (Semen Ziziphi Spinosae), which is a commonly used herb in Chinese and Korean traditional medicines. Considering the basicity of cyclopeptide alkaloids, a specific separation method was developed for an UHPLC system. The compounds were detected by DAD and ESI-qTOF-MS, and their fragmentation patterns were also acquired by MS^{E} technologies. Peak-picking of major compounds was performed with nine previously isolated compounds and two reference standard compounds. Tandem MS fragmentation behaviors of type-Ia and -Ib cyclopeptide alkaloids were investigated with the acquired data to develop a strategy for dereplication of other cyclopeptide alkaloid compounds in Z. jujuba var. spinosa. Two more cyclopeptide alkaloids were tentatively identified with UHPLC-ESI-qTOF-MS using this method.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"229 1","pages":"45-49"},"PeriodicalIF":0.5,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73162516","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}
Ranhee Park, S. Lim, Sun-ho Han, Min Young Lee, Jinkyu Park, Chi-Gyu Lee, K. Song
: Multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) is currently used in our laboratory for isotopic and quantitative analyses of nuclear materials at ultra-trace levels in environmental swipe samples, which is a very useful for monitoring undeclared nuclear activities. In this study, to improve measurement precisions of uranium isotopes at ultra-trace levels, we adopted a desolvating nebulizer system (Aridus-II, CETAC., USA), which can improve signal sensitivity and reduce formation of uranium hydride. A peristaltic pump was combined with Aridus-II in the sample introduction system of MC-ICP-MS to reduce long-term signal fluctuations by maintaining a constant flow rate of the sample solution. The signal sensitivity in the presence of Aridus-II was improved more than 10-fold and the formation ratio of UH/U decreased by 16- to 17-fold compared to a normal spray chamber. Long-term signal fluctuations were significantly reduced by using the peristaltic pump. Detailed optimizations and evaluations with uranium standards are also discussed in this paper.
{"title":"Improvement of Measurement Precisions for Uranium Isotopes at Ultra Trace Levels by Modification of the Sample Introduction System in MC-ICP-MS","authors":"Ranhee Park, S. Lim, Sun-ho Han, Min Young Lee, Jinkyu Park, Chi-Gyu Lee, K. Song","doi":"10.5478/MSL.2016.7.2.50","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.2.50","url":null,"abstract":": Multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) is currently used in our laboratory for isotopic and quantitative analyses of nuclear materials at ultra-trace levels in environmental swipe samples, which is a very useful for monitoring undeclared nuclear activities. In this study, to improve measurement precisions of uranium isotopes at ultra-trace levels, we adopted a desolvating nebulizer system (Aridus-II, CETAC., USA), which can improve signal sensitivity and reduce formation of uranium hydride. A peristaltic pump was combined with Aridus-II in the sample introduction system of MC-ICP-MS to reduce long-term signal fluctuations by maintaining a constant flow rate of the sample solution. The signal sensitivity in the presence of Aridus-II was improved more than 10-fold and the formation ratio of UH/U decreased by 16- to 17-fold compared to a normal spray chamber. Long-term signal fluctuations were significantly reduced by using the peristaltic pump. Detailed optimizations and evaluations with uranium standards are also discussed in this paper.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"6 1","pages":"50-54"},"PeriodicalIF":0.5,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80783590","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}
: Secondary ion mass spectrometry (SIMS) is a promising tool to measure isotope ratios of individual uranium particles in environmental samples for nuclear safeguards. However, the analysis requires prior identification of a small number of uranium particles that coexist with a large number of other particles without uranium. In the present study, this identification was performed by scanning electron microscopy - energy dispersive X-ray analysis with automated particle search mode. The analytical results for an environmental sample taken at a nuclear facility indicated that the observation of backscattered electron images with × 1000 magnification was appropriate to efficiently identify uranium particles. Lower magnification (less than × 500) made it difficult to detect smaller particles of approximately 1 µ m diameter. After identification, each particle was manipulated and transferred for subsequent isotope ratio analysis by SIMS. Consequently, the isotope ratios of individual uranium particles were successfully determined without any molecular ion interference. It was demonstrated that the proposed technique provides a powerful tool to measure individual particles not only for nuclear safeguards but also for environmental sciences.
{"title":"Uranium Particle Identification with SEM-EDX for Isotopic Analysis by Secondary Ion Mass Spectrometry","authors":"F. Esaka, M. Magara","doi":"10.5478/MSL.2016.7.2.41","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.2.41","url":null,"abstract":": Secondary ion mass spectrometry (SIMS) is a promising tool to measure isotope ratios of individual uranium particles in environmental samples for nuclear safeguards. However, the analysis requires prior identification of a small number of uranium particles that coexist with a large number of other particles without uranium. In the present study, this identification was performed by scanning electron microscopy - energy dispersive X-ray analysis with automated particle search mode. The analytical results for an environmental sample taken at a nuclear facility indicated that the observation of backscattered electron images with × 1000 magnification was appropriate to efficiently identify uranium particles. Lower magnification (less than × 500) made it difficult to detect smaller particles of approximately 1 µ m diameter. After identification, each particle was manipulated and transferred for subsequent isotope ratio analysis by SIMS. Consequently, the isotope ratios of individual uranium particles were successfully determined without any molecular ion interference. It was demonstrated that the proposed technique provides a powerful tool to measure individual particles not only for nuclear safeguards but also for environmental sciences.","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"11 1","pages":"41-44"},"PeriodicalIF":0.5,"publicationDate":"2016-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73242180","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}
A. Radionova, D. Greenwood, G. Willmott, P. Derrick
Abstract : Dual-channel nano-electrospray has recently become an ionization technique of great promise especially in biologi-cal mass spectrometry. This unique approach takes advantage of the mixing processes that occurs during electrospray. Under-standing in more detail the fundamental principles influencing spray formation further study of the origins of the mixingprocesses: (1) in a Taylor cone region, (2) in charged droplets or (3) in both environments. The dual-channel emitters were mad efrom borosilicate theta-shape glass tubes (O.D. 1.2 mm) and had a tip diameters of less than 4µm. Electrical contact wasachived by deposition of a thin film of an appropriate metal onto the surface of the emitter. The experimental investigation ofthe Taylor cone formation in a dual-channel electrospray emitter has been carried out by injection of polystyrene beads(diameter 3µm) at very low concentrations into one of the channels of the non-tapered theta-glass tubes. High-speed cameraexperiments were set up to visualize the mixing processes in Taylor cone regions for dual-channel emitters. Mass spectra fromdual nano-electrospray are presented.Keywords : nano-electrospray, theta-shaped dual channel emitters, Taylor cone, mass spectrometry
{"title":"Dual Nano-Electrospray and Mixing in the Taylor Cone","authors":"A. Radionova, D. Greenwood, G. Willmott, P. Derrick","doi":"10.5478/MSL.2016.7.1.21","DOIUrl":"https://doi.org/10.5478/MSL.2016.7.1.21","url":null,"abstract":"Abstract : Dual-channel nano-electrospray has recently become an ionization technique of great promise especially in biologi-cal mass spectrometry. This unique approach takes advantage of the mixing processes that occurs during electrospray. Under-standing in more detail the fundamental principles influencing spray formation further study of the origins of the mixingprocesses: (1) in a Taylor cone region, (2) in charged droplets or (3) in both environments. The dual-channel emitters were mad efrom borosilicate theta-shape glass tubes (O.D. 1.2 mm) and had a tip diameters of less than 4µm. Electrical contact wasachived by deposition of a thin film of an appropriate metal onto the surface of the emitter. The experimental investigation ofthe Taylor cone formation in a dual-channel electrospray emitter has been carried out by injection of polystyrene beads(diameter 3µm) at very low concentrations into one of the channels of the non-tapered theta-glass tubes. High-speed cameraexperiments were set up to visualize the mixing processes in Taylor cone regions for dual-channel emitters. Mass spectra fromdual nano-electrospray are presented.Keywords : nano-electrospray, theta-shaped dual channel emitters, Taylor cone, mass spectrometry","PeriodicalId":18238,"journal":{"name":"Mass Spectrometry Letters","volume":"31 1","pages":"21-25"},"PeriodicalIF":0.5,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74716084","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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