Capillary Photoionization: A High Sensitivity Ionization Method for Mass Spectrometry

Research output: Contribution to journalArticleScientificpeer-review

Abstract

We present a capillary photoionization (CPI) method for mass spectrometric (MS) analysis of liquid and gaseous samples. CPI utilizes a heated transfer capillary with a vacuum ultraviolet transparent MgF2 window, through which vacuum UV light (10 eV) from an external source enters the capillary. The liquid or gaseous sample, together with dopant, is introduced directly into the heated transfer capillary between the atmosphere and the vacuum of the MS. Since the sample is vaporized and photoionized inside the capillary, ion transmission is maximized, resulting in good overall sensitivity for nonpolar and polar compounds. As in atmospheric pressure photoionization, ionization in CPI occurs either by proton transfer or by charge exchange reactions. The feasibility of CPI was demonstrated with selected nonpolar and polar compounds. A particular advantage of CPI is that it enables the analysis of nonvolatile and nonpolar compounds in liquid samples with high ionization efficiency. This is not possible with existing capillary ionization methods. The performance of CPI as an interface between GC and MS and its applicability for the analysis of steroids in biological samples are also demonstrated. The GC-CPI-MS method shows good chromatographic resolution, linearity (R2 > 0.993), limits of detection (LOD) in the range of 2–6 pg/mL and repeatability of injection with relative standard deviations of 4–15%.
Original languageEnglish
JournalAnalytical Chemistry
Volume85
Issue number12
Pages (from-to)5715-5719
Number of pages5
ISSN0003-2700
DOIs
Publication statusPublished - 28 May 2013
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 317 Pharmacy

Cite this

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title = "Capillary Photoionization: A High Sensitivity Ionization Method for Mass Spectrometry",
abstract = "We present a capillary photoionization (CPI) method for mass spectrometric (MS) analysis of liquid and gaseous samples. CPI utilizes a heated transfer capillary with a vacuum ultraviolet transparent MgF2 window, through which vacuum UV light (10 eV) from an external source enters the capillary. The liquid or gaseous sample, together with dopant, is introduced directly into the heated transfer capillary between the atmosphere and the vacuum of the MS. Since the sample is vaporized and photoionized inside the capillary, ion transmission is maximized, resulting in good overall sensitivity for nonpolar and polar compounds. As in atmospheric pressure photoionization, ionization in CPI occurs either by proton transfer or by charge exchange reactions. The feasibility of CPI was demonstrated with selected nonpolar and polar compounds. A particular advantage of CPI is that it enables the analysis of nonvolatile and nonpolar compounds in liquid samples with high ionization efficiency. This is not possible with existing capillary ionization methods. The performance of CPI as an interface between GC and MS and its applicability for the analysis of steroids in biological samples are also demonstrated. The GC-CPI-MS method shows good chromatographic resolution, linearity (R2 > 0.993), limits of detection (LOD) in the range of 2–6 pg/mL and repeatability of injection with relative standard deviations of 4–15{\%}.",
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author = "Markus Haapala and Tina Suominen and Risto Kostiainen",
year = "2013",
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doi = "10.1021/ac4002673",
language = "English",
volume = "85",
pages = "5715--5719",
journal = "Analytical Chemistry",
issn = "0003-2700",
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Capillary Photoionization: A High Sensitivity Ionization Method for Mass Spectrometry. / Haapala, Markus; Suominen, Tina; Kostiainen, Risto.

In: Analytical Chemistry, Vol. 85, No. 12, 28.05.2013, p. 5715-5719.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Capillary Photoionization: A High Sensitivity Ionization Method for Mass Spectrometry

AU - Haapala, Markus

AU - Suominen, Tina

AU - Kostiainen, Risto

PY - 2013/5/28

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N2 - We present a capillary photoionization (CPI) method for mass spectrometric (MS) analysis of liquid and gaseous samples. CPI utilizes a heated transfer capillary with a vacuum ultraviolet transparent MgF2 window, through which vacuum UV light (10 eV) from an external source enters the capillary. The liquid or gaseous sample, together with dopant, is introduced directly into the heated transfer capillary between the atmosphere and the vacuum of the MS. Since the sample is vaporized and photoionized inside the capillary, ion transmission is maximized, resulting in good overall sensitivity for nonpolar and polar compounds. As in atmospheric pressure photoionization, ionization in CPI occurs either by proton transfer or by charge exchange reactions. The feasibility of CPI was demonstrated with selected nonpolar and polar compounds. A particular advantage of CPI is that it enables the analysis of nonvolatile and nonpolar compounds in liquid samples with high ionization efficiency. This is not possible with existing capillary ionization methods. The performance of CPI as an interface between GC and MS and its applicability for the analysis of steroids in biological samples are also demonstrated. The GC-CPI-MS method shows good chromatographic resolution, linearity (R2 > 0.993), limits of detection (LOD) in the range of 2–6 pg/mL and repeatability of injection with relative standard deviations of 4–15%.

AB - We present a capillary photoionization (CPI) method for mass spectrometric (MS) analysis of liquid and gaseous samples. CPI utilizes a heated transfer capillary with a vacuum ultraviolet transparent MgF2 window, through which vacuum UV light (10 eV) from an external source enters the capillary. The liquid or gaseous sample, together with dopant, is introduced directly into the heated transfer capillary between the atmosphere and the vacuum of the MS. Since the sample is vaporized and photoionized inside the capillary, ion transmission is maximized, resulting in good overall sensitivity for nonpolar and polar compounds. As in atmospheric pressure photoionization, ionization in CPI occurs either by proton transfer or by charge exchange reactions. The feasibility of CPI was demonstrated with selected nonpolar and polar compounds. A particular advantage of CPI is that it enables the analysis of nonvolatile and nonpolar compounds in liquid samples with high ionization efficiency. This is not possible with existing capillary ionization methods. The performance of CPI as an interface between GC and MS and its applicability for the analysis of steroids in biological samples are also demonstrated. The GC-CPI-MS method shows good chromatographic resolution, linearity (R2 > 0.993), limits of detection (LOD) in the range of 2–6 pg/mL and repeatability of injection with relative standard deviations of 4–15%.

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