Limits...
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.

Show MeSH

Related in: MedlinePlus

Calibration curve obtained from urine samples spiked with creatinine.(A) EICs of the ions at m/z 227 (red) and 153 (green) obtained from the 100-fold diluted urine samples spiked with creatinine with the concentrations of (A) 1.25×10−6 M, (B) 2.50×10−6 M, (C) 5.00×10−6 M, (D) 1.00×10−5 M, and (E), 1.30×10−5. Cystamine (10−5 M, MH+ = 153) was added to the urine samples as the internal standard (green curve). (F) Plot obtained from the ratio of the peak area at m/z 227 (A227) to the peak area at m/z 153 (A153) versus the concentration of creatinine spiked in the urine samples.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3675195&req=5

pone-0066292-g007: Calibration curve obtained from urine samples spiked with creatinine.(A) EICs of the ions at m/z 227 (red) and 153 (green) obtained from the 100-fold diluted urine samples spiked with creatinine with the concentrations of (A) 1.25×10−6 M, (B) 2.50×10−6 M, (C) 5.00×10−6 M, (D) 1.00×10−5 M, and (E), 1.30×10−5. Cystamine (10−5 M, MH+ = 153) was added to the urine samples as the internal standard (green curve). (F) Plot obtained from the ratio of the peak area at m/z 227 (A227) to the peak area at m/z 153 (A153) versus the concentration of creatinine spiked in the urine samples.

Mentions: We also examined the result by spiking different concentrations of creatinine to 100-fold diluted urine. A given concentration of cystamine was spiked in the urine samples as the internal standard. The analysis of the samples containing different concentrations of creatinine spiked with the same concentration of cystamine (10−5 M) was repeated three times. Figures 7A-7E show the EIC plots at m/z 227 and 153 obtained from the 100-fold diluted urine samples spiked with different concentrations of creatinine and a given concentration of cystamine (10−5 M) for three replicates. The calibration curve was obtained using the current approach by plotting the ratio of the peak area of the peak at m/z 227 derived from creatinine dimer ions to the peak at m/z 153 derived from protonated cystamine ions (Fig. 7F). An acceptable linear calibration curve was obtained. The results indicated that using this current approach for quantitative analysis of complex samples is possible. Nevertheless, the setup should be further improved to reduce potential problems such as solvent evaporation during the 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)

Calibration curve obtained from urine samples spiked with creatinine.(A) EICs of the ions at m/z 227 (red) and 153 (green) obtained from the 100-fold diluted urine samples spiked with creatinine with the concentrations of (A) 1.25×10−6 M, (B) 2.50×10−6 M, (C) 5.00×10−6 M, (D) 1.00×10−5 M, and (E), 1.30×10−5. Cystamine (10−5 M, MH+ = 153) was added to the urine samples as the internal standard (green curve). (F) Plot obtained from the ratio of the peak area at m/z 227 (A227) to the peak area at m/z 153 (A153) versus the concentration of creatinine spiked in the urine samples.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675195&req=5

pone-0066292-g007: Calibration curve obtained from urine samples spiked with creatinine.(A) EICs of the ions at m/z 227 (red) and 153 (green) obtained from the 100-fold diluted urine samples spiked with creatinine with the concentrations of (A) 1.25×10−6 M, (B) 2.50×10−6 M, (C) 5.00×10−6 M, (D) 1.00×10−5 M, and (E), 1.30×10−5. Cystamine (10−5 M, MH+ = 153) was added to the urine samples as the internal standard (green curve). (F) Plot obtained from the ratio of the peak area at m/z 227 (A227) to the peak area at m/z 153 (A153) versus the concentration of creatinine spiked in the urine samples.
Mentions: We also examined the result by spiking different concentrations of creatinine to 100-fold diluted urine. A given concentration of cystamine was spiked in the urine samples as the internal standard. The analysis of the samples containing different concentrations of creatinine spiked with the same concentration of cystamine (10−5 M) was repeated three times. Figures 7A-7E show the EIC plots at m/z 227 and 153 obtained from the 100-fold diluted urine samples spiked with different concentrations of creatinine and a given concentration of cystamine (10−5 M) for three replicates. The calibration curve was obtained using the current approach by plotting the ratio of the peak area of the peak at m/z 227 derived from creatinine dimer ions to the peak at m/z 153 derived from protonated cystamine ions (Fig. 7F). An acceptable linear calibration curve was obtained. The results indicated that using this current approach for quantitative analysis of complex samples is possible. Nevertheless, the setup should be further improved to reduce potential problems such as solvent evaporation during the 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