Optimization of short-column gas chromatography/electron ionization mass spectrometry conditions for the determination of underivatized anabolic steroids

Rossi, Stacy-Ann; Johnson, Jodie V.; Yost, Richard A.

doi:10.1002/bms.1200210903

Cited by 11 publications

(8 citation statements)

References 19 publications

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“…Usually the GC-MS of steroids is performed after their derivatization. However, a short column fast GC-MS of underivatized steroids was recently reported [1]. During the analysis of thermally labile steroids we realized that different steroids possess different degrees of thermolability.…”

Section: Gc-ms Analysis Of Underivatized Steroids and The Speed Enhanmentioning

confidence: 99%

“…We note, however, that the SEF does not necessarily directly reflect the exact reduction of the analysis time because this is affected also by the column temperature and its programming rate, especially where very short analysis periods are concerned. In relation to our definition of SEF, we advance here a subclassification of GC-MS in relation to the SEF: (1) Normal GC-MS is performed with SEF around 1; (2) fast GC-MS is performed with SEF in the range of 5-30 (about 10); (3) very fast GC-MS is defined with SEF in the range of 30-400 (about 100); (4) ultra-fast GC-MS is defined as a GC-MS with SEF in the range 400-4000 (about 1000).…”

Section: Gc-ms Analysis Of Underivatized Steroids and The Speed Enhanmentioning

confidence: 99%

“…We used three types of syringes: (1) SGE (Australia) model 034055 "plunger-in" 1-JLL syringe . This syringe performed poorly with thermally labile molecules due to its relatively large metal surface area.…”

Section: Experimental Parameters That Affect the Gc-ms Of Thermally Lmentioning

confidence: 99%

“…Three megabore columns were used: (1) J& W Scientific (Folsom, CA) with DB-1 film, 0.15-JLm film thickness; (2) SGE with BPX5 film, 0.25-JLm film thickness; (3) SGE with illS film, 0.15-JLm film thickness. We observed no differences in the performance of these columns.…”

Section: Experimental Parameters That Affect the Gc-ms Of Thermally Lmentioning

confidence: 99%

“…An obvious and known approach to further enhance the scope of GC-MS with thermally labile compounds is to use a short column for fast GC to reduce the residence time of the molecule in the separation column and thereby to minimize its dissociation [1][2][3][4]. Several methods of fast GC-MS have been developed, which include: 1. The "open split" method [5], which is perhaps the simplest method.…”

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Fast, very fast, and ultra-fast gas chromatography-mass spectrometry of thermally labile steroids, carbamates, and drugs in supersonic molecular beams

DAGAN¹,

AMIRAV²

1996

Journal of the American Society for Mass Spectrometry

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Aviv 69978, Tel Aviv, Israel Gas chromatography-mass spectrometry (GC-MS) analyses of thermally labile compounds have been studied by using a short column fast gas chromatograph, coupled with fly-through electron ionization in supersonic molecular beams. Thirty-two compounds, which include steroids, carbamate pesticides, antibiotic drugs, and other pharmaceutical compounds, have been analyzed and the details of their GC-MS analysis are provided. The ability to analyze thermally labile compounds is discussed in relation to the speed of analysis. A new term, "speed enhancement factor" (SEF), is defined as the product of column length reduction and the carrier gas linear velocity increase, as compared with normal GC-MS conditions. Fast, very fast, and ultra-fast GC-MS are defined with a SEF in the ranges of 5-30,30-400, and 400-4000, respectively. Trade-offs in the degree of dissociation, speed, gas chromatograph resolution, and sensitivity were studied and examined with thermally labile molecules . The experimental factors that affect the dissociation are described with emphasis on its reduction. We claim that the use of supersonic molecular beams for sampling and ionization provides the ultimate capability in the GC-MS of thermally labile compounds. The obtained 70-eV electron ionization mass spectra are shown, and an enhanced relative abundance of the molecular ion is demonstrated together with library search capability of these mass spectra, which is better than that reported with particle beam liquid chromatography-mass spectrometry. The performance of fast GC-MS in supersonic molecular beams is compared with other methods of fast GC-MS and with particle beam liquid chromatography-mass spectrometry. (J Am Soc Mass Spectrom 1996, 7, 737-752) G as chromatography-mass spectrometry (GC-MS) is the central technique employed today for the analysis of organic compounds, which includes analysis at trace levels in complex mixtures. However, GC-MS is limited in its scope and therefore is often replaced by liquid chromatography-mass spectrometry (LC-MS), although LC-MS analysis is more complicated to operate, exhibits poorer performance, and costs more .The scope of conventional GC-MS is limited owing to two main reasons:1. Relatively nonvolatile molecules (such as large polycyclic aromatic hydrocarbons) are incompatible with gas chromatography and especially incompatible with the mass spectrometer ion source. The ion source-limited temperature results in an early onset of chromatographic peak tailing.Address reprint requests to Professor Aviv Am irav, School of Chemistry, Sadder Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.

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Section: Gc-ms Analysis Of Underivatized Steroids and The Speed Enhanmentioning

confidence: 99%

Section: Gc-ms Analysis Of Underivatized Steroids and The Speed Enhanmentioning

confidence: 99%

Section: Experimental Parameters That Affect the Gc-ms Of Thermally Lmentioning

confidence: 99%

Section: Experimental Parameters That Affect the Gc-ms Of Thermally Lmentioning

confidence: 99%

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confidence: 99%

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Fast, very fast, and ultra-fast gas chromatography-mass spectrometry of thermally labile steroids, carbamates, and drugs in supersonic molecular beams

DAGAN¹,

AMIRAV²

1996

Journal of the American Society for Mass Spectrometry

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Ultrafast gas chromatography using time-of-flight mass spectrometry

Davis¹,

Makarov²,

Hughes³

1999

Rapid Commun. Mass Spectrom.

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Gas chromatograph/mass spectrometric analyses typically require several tens of minutes to run. In a laboratory requiring high sample throughput there is an obvious benefit to being able to significantly reduce run times. Shorter run times can be realised using one or more of a number of techniques, depending on the analytical objectives. Whether the shortened run has very narrow peaks with good separation or wider peaks with compromised separation, the ability to produce mass spectra at a high rate offers advantages. Copyright # 1999 John Wiley & Sons, Ltd. Received 27 September 1998; Revised 4 November 1998; Accepted 5 November 1998 Fast gas chromatography/mass spectrometry (GC/MS) can be done with short lengths of column with diameters ranging from MicroBore 1 to MegaBore 2 column i.d. 0.05-0.15 mm and 0.52 mm, respectively. The optimum column flow rate depends on the column diameter, and the mass spectrometer interface has to be compatible with the gas load from the selected column. Most GC/MS instruments are designed to cope with flow rates below 1-2 mL/min, which means column diameters need to be relatively small so as not to overload the mass spectrometer vacuum system. Short lengths of MicroBore column provide relatively low flow rates and maintain a high level of chromatographic separation. High separation efficiency in a short run time means very narrow temporal peak widths for the analytes eluting into the mass spectrometer ion source. MicroBore GC peak widths can be less than 100 milliseconds. Such narrow peak widths make full scan mass spectral data very difficult, if not impossible, to acquire using scanning mass spectrometers. The high data acquisition rates afforded by time-of-flight (TOF) mass spectrometers mean that TOFMS is capable of acquiring full scan mass spectra across even the narrowest MicroBore GC peak.Short lengths of MegaBore column have very small nonretained peak retention times but operate with high gas flow rates which cannot be used with conventional GC/MS inlets. A supersonic molecular beam (SMB) inlet can be coupled to any column, including short lengths of MegaBore column. However, short MegaBore systems do not offer very high chromatographic resolution. With a TOF mass spectrometer, the large rate of data collection aids deconvolution algorithms which can offset, to a certain extent, the limited separating power of a short MegaBore system. This is also true for any column diameter where the run time has been reduced at the expense of separation efficiency, or where the complexity of the mixture prevents complete resolution of all peaks.NarrowBore systems (0.25 and 0.32 mm i.d. columns) are widely used, available and understood. They offer a dynamic range which closely matches that of MS systems, making them the ideal platform for runtime compression development. Reduced analysis times using NarrowBore columns are possible by refocusing analytes after the injector stage and then flash desorbing them through the column which is held throughout at a high, isothermal temperatu...

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A Simple Way to Speed up Separations by GC-MS Using Short 0.53 mm Columns and Vacuum Outlet Conditions

Zeeuw¹,

Peene²,

Jansen

et al. 2000

J. High Resol. Chromatogr.

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Optimization of short-column gas chromatography/electron ionization mass spectrometry conditions for the determination of underivatized anabolic steroids

Cited by 11 publications

References 19 publications

Fast, very fast, and ultra-fast gas chromatography-mass spectrometry of thermally labile steroids, carbamates, and drugs in supersonic molecular beams

Fast, very fast, and ultra-fast gas chromatography-mass spectrometry of thermally labile steroids, carbamates, and drugs in supersonic molecular beams

Ultrafast gas chromatography using time-of-flight mass spectrometry

A Simple Way to Speed up Separations by GC-MS Using Short 0.53 mm Columns and Vacuum Outlet Conditions

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