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New automated and high-throughput quantitative analysis of urinary ketones by multifiber exchange-solid phase microextraction coupled to fast gas chromatography/negative chemical-electron ionization/mass spectrometry.

Pacenti M, Dugheri S, Traldi P, Degli Esposti F, Perchiazzi N, Franchi E, Calamante M, Kikic I, Alessi P, Bonacchi A, Salvadori E, Arcangeli G, Cupelli V - J Autom Methods Manag Chem (2010)

Bottom Line: The present research is focused on automation, miniaturization, and system interaction with high throughput for multiple and specific Direct Immersion-Solid Phase Microextraction/Fast Gas Chromatography analysis of the urinary ketones.The specific Mass Spectrometry instrumentation, capable of supporting such the automated changeover from Negative Chemical to Electron Ionization mode, as well as the automation of the preparation procedure by new device called MultiFiber Exchange, through change of the fibers, allowed a friendly use of mass spectrometry apparatus with a number of advantages including reduced analyst time and greater reproducibility (2.01-5.32%).The detection limits for the seven ketones were less than 0.004 mg/L.

View Article: PubMed Central - PubMed

Affiliation: Occupational Health Division, Department of Public Health, Viale Morgagni 48, University of Florence, 50100 Florence, Italy.

ABSTRACT
The present research is focused on automation, miniaturization, and system interaction with high throughput for multiple and specific Direct Immersion-Solid Phase Microextraction/Fast Gas Chromatography analysis of the urinary ketones. The specific Mass Spectrometry instrumentation, capable of supporting such the automated changeover from Negative Chemical to Electron Ionization mode, as well as the automation of the preparation procedure by new device called MultiFiber Exchange, through change of the fibers, allowed a friendly use of mass spectrometry apparatus with a number of advantages including reduced analyst time and greater reproducibility (2.01-5.32%). The detection limits for the seven ketones were less than 0.004 mg/L. For an innovative powerful meaning in high-throughput routine, the generality of the structurally informative Mass Spectrometry fragmentation patterns together with the chromatographic separation and software automation are also investigated.

No MeSH data available.


Related in: MedlinePlus

Fast GC/MS chromatogram of the organic ketone derivatives by EI (Figure 5(a)) and NCI (Figure 5(b)) mode.
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fig5: Fast GC/MS chromatogram of the organic ketone derivatives by EI (Figure 5(a)) and NCI (Figure 5(b)) mode.

Mentions: A low recovery of corresponding oxime was observed only for ketones contain chlorine atoms. In fact, the reactivity of chloroketone with PFBHA is triggered by the chloro-substitution in the principal product [28]. Herein to verify the drawbacks with indicated above methods and in light of previous works [29, 30], the authors investigated the derivatization with PFBHA. The reaction was evaluated concerning the effect of the reaction time and product yield attained by the determination of the amount of ketones converting to corresponding oximes. Briefly, 5 mL of water containing 2 μg of MEK, MIBK, Chone, 2,5 HD, and Ace were doped with 1 mL of PFBHA solution (40 mg/mL). The samples were left to three experimental derivatization reaction settings (20 hours at 25°C, 1 hour at 25°C, and 30 minutes to 65°C) for establishing the conditions that minimize the time needed for preparation. After incubations, the oximes were extracted twice with 1 mL of hexane and 0.3 μL was analyzed. The GC area counts were compared with the amount of Ace-, MEK-, MIBK-, Chone-, and 2,5 HD-PFBHA-oxime standards previously injected by Fast GC/NCI/MS. For 20 hours at 25°C incubation ketones were converted in their corresponding derivatives with values of 99% and no decomposition of PFBHA-oximes was observed (Figure 3). However, the reaction yield after 30 minutes to 65°C is enough for the formation of products also ensuring fastness in the application of the method. If higher sensitivity is aimed, the reaction time and exposure fiber can be prolonged based on the profile of the reaction and absorption progress (Figure 4). No decomposition of the excess of derivatization agent by adding 5 μL of 9 M sulfuric acid was necessary if overnight incubation was employed. Eventually, the selective reduction of this bond with pyridine:borane reagent leads to single GC peak for each compound [31]. For following sampling by DI, the effect of agitation and the absorption-time profiles on the SPME extraction efficiency of the derivatives of these carbonyl compounds were examined. The agitation of the solution can strongly improve the SPME extraction process and the equilibrium times increased with increasing molecular mass of the analytes (Table 1). Since the extraction with SPME is based on an equilibrium between the analyte concentrations in the liquid and fiber coating, it is not necessary to reach an absorption equilibrium for quantitative analysis if the absorption time and mixing conditions are held constant throughout the experiment. Thus, a 5-min extraction time was employed because this yielded sufficient extraction and excellent precision data (Table 2). Except for Ace-PFBHA-oxime, with a single chromatographic peak, for the other ketone-PFBHA-oximes the formation of a double peak, corresponding to syn- and anti-isomer, was observed (Figure 5) and the total area of the two peaks was used for their quantitative determination. The PFBHA by on-sample derivatization was so chosen for this work, because it is commercially avaiable and, under these conditions, the method allows for the selective detection of ketones at a very low levels without interferences.


New automated and high-throughput quantitative analysis of urinary ketones by multifiber exchange-solid phase microextraction coupled to fast gas chromatography/negative chemical-electron ionization/mass spectrometry.

Pacenti M, Dugheri S, Traldi P, Degli Esposti F, Perchiazzi N, Franchi E, Calamante M, Kikic I, Alessi P, Bonacchi A, Salvadori E, Arcangeli G, Cupelli V - J Autom Methods Manag Chem (2010)

Fast GC/MS chromatogram of the organic ketone derivatives by EI (Figure 5(a)) and NCI (Figure 5(b)) mode.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2902044&req=5

fig5: Fast GC/MS chromatogram of the organic ketone derivatives by EI (Figure 5(a)) and NCI (Figure 5(b)) mode.
Mentions: A low recovery of corresponding oxime was observed only for ketones contain chlorine atoms. In fact, the reactivity of chloroketone with PFBHA is triggered by the chloro-substitution in the principal product [28]. Herein to verify the drawbacks with indicated above methods and in light of previous works [29, 30], the authors investigated the derivatization with PFBHA. The reaction was evaluated concerning the effect of the reaction time and product yield attained by the determination of the amount of ketones converting to corresponding oximes. Briefly, 5 mL of water containing 2 μg of MEK, MIBK, Chone, 2,5 HD, and Ace were doped with 1 mL of PFBHA solution (40 mg/mL). The samples were left to three experimental derivatization reaction settings (20 hours at 25°C, 1 hour at 25°C, and 30 minutes to 65°C) for establishing the conditions that minimize the time needed for preparation. After incubations, the oximes were extracted twice with 1 mL of hexane and 0.3 μL was analyzed. The GC area counts were compared with the amount of Ace-, MEK-, MIBK-, Chone-, and 2,5 HD-PFBHA-oxime standards previously injected by Fast GC/NCI/MS. For 20 hours at 25°C incubation ketones were converted in their corresponding derivatives with values of 99% and no decomposition of PFBHA-oximes was observed (Figure 3). However, the reaction yield after 30 minutes to 65°C is enough for the formation of products also ensuring fastness in the application of the method. If higher sensitivity is aimed, the reaction time and exposure fiber can be prolonged based on the profile of the reaction and absorption progress (Figure 4). No decomposition of the excess of derivatization agent by adding 5 μL of 9 M sulfuric acid was necessary if overnight incubation was employed. Eventually, the selective reduction of this bond with pyridine:borane reagent leads to single GC peak for each compound [31]. For following sampling by DI, the effect of agitation and the absorption-time profiles on the SPME extraction efficiency of the derivatives of these carbonyl compounds were examined. The agitation of the solution can strongly improve the SPME extraction process and the equilibrium times increased with increasing molecular mass of the analytes (Table 1). Since the extraction with SPME is based on an equilibrium between the analyte concentrations in the liquid and fiber coating, it is not necessary to reach an absorption equilibrium for quantitative analysis if the absorption time and mixing conditions are held constant throughout the experiment. Thus, a 5-min extraction time was employed because this yielded sufficient extraction and excellent precision data (Table 2). Except for Ace-PFBHA-oxime, with a single chromatographic peak, for the other ketone-PFBHA-oximes the formation of a double peak, corresponding to syn- and anti-isomer, was observed (Figure 5) and the total area of the two peaks was used for their quantitative determination. The PFBHA by on-sample derivatization was so chosen for this work, because it is commercially avaiable and, under these conditions, the method allows for the selective detection of ketones at a very low levels without interferences.

Bottom Line: The present research is focused on automation, miniaturization, and system interaction with high throughput for multiple and specific Direct Immersion-Solid Phase Microextraction/Fast Gas Chromatography analysis of the urinary ketones.The specific Mass Spectrometry instrumentation, capable of supporting such the automated changeover from Negative Chemical to Electron Ionization mode, as well as the automation of the preparation procedure by new device called MultiFiber Exchange, through change of the fibers, allowed a friendly use of mass spectrometry apparatus with a number of advantages including reduced analyst time and greater reproducibility (2.01-5.32%).The detection limits for the seven ketones were less than 0.004 mg/L.

View Article: PubMed Central - PubMed

Affiliation: Occupational Health Division, Department of Public Health, Viale Morgagni 48, University of Florence, 50100 Florence, Italy.

ABSTRACT
The present research is focused on automation, miniaturization, and system interaction with high throughput for multiple and specific Direct Immersion-Solid Phase Microextraction/Fast Gas Chromatography analysis of the urinary ketones. The specific Mass Spectrometry instrumentation, capable of supporting such the automated changeover from Negative Chemical to Electron Ionization mode, as well as the automation of the preparation procedure by new device called MultiFiber Exchange, through change of the fibers, allowed a friendly use of mass spectrometry apparatus with a number of advantages including reduced analyst time and greater reproducibility (2.01-5.32%). The detection limits for the seven ketones were less than 0.004 mg/L. For an innovative powerful meaning in high-throughput routine, the generality of the structurally informative Mass Spectrometry fragmentation patterns together with the chromatographic separation and software automation are also investigated.

No MeSH data available.


Related in: MedlinePlus