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Automatic sampling and analysis of organics and biomolecules by capillary action-supported contactless atmospheric pressure ionization mass spectrometry.

Hsieh CH, Meher AK, Chen YC - PLoS ONE (2013)

Bottom Line: No carryover problems are observed during the analyses.The sample volume required for the C-API MS analysis is minimal, with less than 1 nL of the sample solution being sufficient for analysis.The feasibility of using this setup for quantitative analysis is also demonstrated.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan.

ABSTRACT
Contactless atmospheric pressure ionization (C-API) method has been recently developed for mass spectrometric analysis. A tapered capillary is used as both the sampling tube and spray emitter in C-API. No electric contact is required on the capillary tip during C-API mass spectrometric analysis. The simple design of the ionization method enables the automation of the C-API sampling system. In this study, we propose an automatic C-API sampling system consisting of a capillary (∼1 cm), an aluminium sample holder, and a movable XY stage for the mass spectrometric analysis of organics and biomolecules. The aluminium sample holder is controlled by the movable XY stage. The outlet of the C-API capillary is placed in front of the orifice of a mass spectrometer, whereas the sample well on the sample holder is moved underneath the capillary inlet. The sample droplet on the well can be readily infused into the C-API capillary through capillary action. When the sample solution reaches the capillary outlet, the sample spray is readily formed in the proximity of the mass spectrometer applied with a high electric field. The gas phase ions generated from the spray can be readily monitored by the mass spectrometer. We demonstrate that six samples can be analyzed in sequence within 3.5 min using this automatic C-API MS setup. Furthermore, the well containing the rinsing solvent is alternately arranged between the sample wells. Therefore, the C-API capillary could be readily flushed between runs. No carryover problems are observed during the analyses. The sample volume required for the C-API MS analysis is minimal, with less than 1 nL of the sample solution being sufficient for analysis. The feasibility of using this setup for quantitative analysis is also demonstrated.

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Related in: MedlinePlus

Multiple sample analysis.Four µL samples of arginine (5×10−6 M, MH+ = 175), histidine (5×10−5 M, MH+ = 156), phenylalanine (10−4 M, MH+ = 166), leucine (10−4 M, MH+ = 132), creatinine (10−4 M, M2H+ = 227), and caffeine (10−4 M, MH+ = 195) were deposited into different wells in two dimensions on the aluminium sample holder as shown in Figure 1. The rinse solvent [acetonitrile/deionized water (1∶1, v/v)] was loaded to alternate with the sample wells for autoflushing after every run. (A) The resultant EIC plots of the ions at m/z 175, 156, 166, 132, 227, and 195. Panels (B) to (G) show the mass spectra obtained at the time points of 0.2 min to 0.5 min, 0.7 min to 1.0 min, 1.3 min to 1.6 min, 1.8 min to 2.1 min, 2.4 min to 2.7 min, and 2.9 min to 3.2 min, respectively, in panel A.
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pone-0066292-g004: Multiple sample analysis.Four µL samples of arginine (5×10−6 M, MH+ = 175), histidine (5×10−5 M, MH+ = 156), phenylalanine (10−4 M, MH+ = 166), leucine (10−4 M, MH+ = 132), creatinine (10−4 M, M2H+ = 227), and caffeine (10−4 M, MH+ = 195) were deposited into different wells in two dimensions on the aluminium sample holder as shown in Figure 1. The rinse solvent [acetonitrile/deionized water (1∶1, v/v)] was loaded to alternate with the sample wells for autoflushing after every run. (A) The resultant EIC plots of the ions at m/z 175, 156, 166, 132, 227, and 195. Panels (B) to (G) show the mass spectra obtained at the time points of 0.2 min to 0.5 min, 0.7 min to 1.0 min, 1.3 min to 1.6 min, 1.8 min to 2.1 min, 2.4 min to 2.7 min, and 2.9 min to 3.2 min, respectively, in panel A.

Mentions: The C-API autosampling system was also employed for multiple sample analyses to show the possibility of using the automatic system for high throughput analysis. Several standards were selected. In addition to amino acids as mentioned above, creatinine was selected as model sample. Creatinine is a common metabolite found in urine. Caffeine is also a common component present in drinks. The sample wells were arranged in two-dimensions on an aluminium plate, as shown in Figure 1. Arginine (MH+ = 175), histidine (MH+ = 156), phenylalanine (MH+ = 166), leucine (MH+ = 132), creatinine (M2H+ = 227), and caffeine (MH+ = 195) were selected as model samples and loaded onto the sample wells on the aluminium plate. The rinse solvent [acetonitrile/deionized water (1∶1, v/v)] was loaded alternately with the sample wells for sampling capillary flushing after every run. Figure 4A shows the EIC plots of the analyte ions at m/z 175, 156, 166, 132, 227, and 195, whereas the corresponding mass spectra obtained at the time points of 0.2 min to 0.5 min, 0.7 min to 1.0 min, 1.3 min to 1.6 min, 1.8 min to 2.1 min, 2.4 min to 2.7 min, and 2.9 min to 3.2 min, respectively, are shown in Figures 4B to 4G. All analyte ion peaks dominated their own mass spectra. Furthermore, no carryover effects were observed. The analysis using six samples was completed within 3.5 min, including six alternate flushings. The results demonstrated that the C-API autosampling system can be used for analyzing many samples within a short period. The flushings of the sampling capillary can be performed automatically and effectively after each run. Cross-contamination problems were not observed during analysis.


Automatic sampling and analysis of organics and biomolecules by capillary action-supported contactless atmospheric pressure ionization mass spectrometry.

Hsieh CH, Meher AK, Chen YC - PLoS ONE (2013)

Multiple sample analysis.Four µL samples of arginine (5×10−6 M, MH+ = 175), histidine (5×10−5 M, MH+ = 156), phenylalanine (10−4 M, MH+ = 166), leucine (10−4 M, MH+ = 132), creatinine (10−4 M, M2H+ = 227), and caffeine (10−4 M, MH+ = 195) were deposited into different wells in two dimensions on the aluminium sample holder as shown in Figure 1. The rinse solvent [acetonitrile/deionized water (1∶1, v/v)] was loaded to alternate with the sample wells for autoflushing after every run. (A) The resultant EIC plots of the ions at m/z 175, 156, 166, 132, 227, and 195. Panels (B) to (G) show the mass spectra obtained at the time points of 0.2 min to 0.5 min, 0.7 min to 1.0 min, 1.3 min to 1.6 min, 1.8 min to 2.1 min, 2.4 min to 2.7 min, and 2.9 min to 3.2 min, respectively, in panel A.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3675195&req=5

pone-0066292-g004: Multiple sample analysis.Four µL samples of arginine (5×10−6 M, MH+ = 175), histidine (5×10−5 M, MH+ = 156), phenylalanine (10−4 M, MH+ = 166), leucine (10−4 M, MH+ = 132), creatinine (10−4 M, M2H+ = 227), and caffeine (10−4 M, MH+ = 195) were deposited into different wells in two dimensions on the aluminium sample holder as shown in Figure 1. The rinse solvent [acetonitrile/deionized water (1∶1, v/v)] was loaded to alternate with the sample wells for autoflushing after every run. (A) The resultant EIC plots of the ions at m/z 175, 156, 166, 132, 227, and 195. Panels (B) to (G) show the mass spectra obtained at the time points of 0.2 min to 0.5 min, 0.7 min to 1.0 min, 1.3 min to 1.6 min, 1.8 min to 2.1 min, 2.4 min to 2.7 min, and 2.9 min to 3.2 min, respectively, in panel A.
Mentions: The C-API autosampling system was also employed for multiple sample analyses to show the possibility of using the automatic system for high throughput analysis. Several standards were selected. In addition to amino acids as mentioned above, creatinine was selected as model sample. Creatinine is a common metabolite found in urine. Caffeine is also a common component present in drinks. The sample wells were arranged in two-dimensions on an aluminium plate, as shown in Figure 1. Arginine (MH+ = 175), histidine (MH+ = 156), phenylalanine (MH+ = 166), leucine (MH+ = 132), creatinine (M2H+ = 227), and caffeine (MH+ = 195) were selected as model samples and loaded onto the sample wells on the aluminium plate. The rinse solvent [acetonitrile/deionized water (1∶1, v/v)] was loaded alternately with the sample wells for sampling capillary flushing after every run. Figure 4A shows the EIC plots of the analyte ions at m/z 175, 156, 166, 132, 227, and 195, whereas the corresponding mass spectra obtained at the time points of 0.2 min to 0.5 min, 0.7 min to 1.0 min, 1.3 min to 1.6 min, 1.8 min to 2.1 min, 2.4 min to 2.7 min, and 2.9 min to 3.2 min, respectively, are shown in Figures 4B to 4G. All analyte ion peaks dominated their own mass spectra. Furthermore, no carryover effects were observed. The analysis using six samples was completed within 3.5 min, including six alternate flushings. The results demonstrated that the C-API autosampling system can be used for analyzing many samples within a short period. The flushings of the sampling capillary can be performed automatically and effectively after each run. Cross-contamination problems were not observed during analysis.

Bottom Line: No carryover problems are observed during the analyses.The sample volume required for the C-API MS analysis is minimal, with less than 1 nL of the sample solution being sufficient for analysis.The feasibility of using this setup for quantitative analysis is also demonstrated.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan.

ABSTRACT
Contactless atmospheric pressure ionization (C-API) method has been recently developed for mass spectrometric analysis. A tapered capillary is used as both the sampling tube and spray emitter in C-API. No electric contact is required on the capillary tip during C-API mass spectrometric analysis. The simple design of the ionization method enables the automation of the C-API sampling system. In this study, we propose an automatic C-API sampling system consisting of a capillary (∼1 cm), an aluminium sample holder, and a movable XY stage for the mass spectrometric analysis of organics and biomolecules. The aluminium sample holder is controlled by the movable XY stage. The outlet of the C-API capillary is placed in front of the orifice of a mass spectrometer, whereas the sample well on the sample holder is moved underneath the capillary inlet. The sample droplet on the well can be readily infused into the C-API capillary through capillary action. When the sample solution reaches the capillary outlet, the sample spray is readily formed in the proximity of the mass spectrometer applied with a high electric field. The gas phase ions generated from the spray can be readily monitored by the mass spectrometer. We demonstrate that six samples can be analyzed in sequence within 3.5 min using this automatic C-API MS setup. Furthermore, the well containing the rinsing solvent is alternately arranged between the sample wells. Therefore, the C-API capillary could be readily flushed between runs. No carryover problems are observed during the analyses. The sample volume required for the C-API MS analysis is minimal, with less than 1 nL of the sample solution being sufficient for analysis. The feasibility of using this setup for quantitative analysis is also demonstrated.

Show MeSH
Related in: MedlinePlus