Isotopic analogs as internal standards for quantitative analyses by GC/MS — evaluation of cross-contribution to ions designated for the analyte and the isotopic internal standard

Chang, Wei-Tun; Lin, Dongliang; Liu, R.H

doi:10.1016/s0379-0738(01)00396-6

Cited by 20 publications

(23 citation statements)

References 10 publications

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“…This later study [10] concluded that "all methods produce practically the same order, among ions derived from each isotopic analog, in their extents in contributing to the intensities of respective ions designated for a specific counter isotopic analog. Thus, all methods can be used to select the best ion-pair within a selected analyte/[IS] for the intended quantitative analysis protocol" [10]. However, the accuracy (trueness) of the empirically determined CC data still could not be assessed.…”

Section: Resultsmentioning

confidence: 98%

“…Thus, a follow-up study [10] was conducted to develop three additional methods (improved direct measurement, internal standard, and standard addition), and they were compared against the method (direct measurement) developed earlier [9]. This later study [10] concluded that "all methods produce practically the same order, among ions derived from each isotopic analog, in their extents in contributing to the intensities of respective ions designated for a specific counter isotopic analog. Thus, all methods can be used to select the best ion-pair within a selected analyte/[IS] for the intended quantitative analysis protocol" [10].…”

Section: Resultsmentioning

confidence: 99%

“…Mass spectrometric data derived from these SIM runs were then used to evaluate the CC data. Details of the methodology have been described in our earlier publications [9,10] and briefly illustrated in the next section using the data derived from the MDA/ MDA-d 5 system as the example.…”

Section: Instrumentation Analytical Parameters and Data Collection mentioning

confidence: 99%

“…We believe this does not invalidate the application of the normalization approach to the HM/HM-d 6 system; instead, it is a reflection of more significant experimental errors incurred in the HM/HM-d 6 study. Further study will be conducted in the future to include other analyte/IS systems and CC data derived from other methods [10].…”

Section: Graphic Presentation On the Evaluation Of CC Data Based On Tmentioning

confidence: 99%

See 3 more Smart Citations

A novel approach to evaluate the extent and the effect of cross-contribution to the intensity of ions designating the analyte and the internal standard in quantitative GC-MS analysis

Chen

Chang²,

Wang

et al. 2008

J. Am. Soc. Mass Spectrom.

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In gas chromatography-mass spectrometry methods of analysis adopting the analyte's isotopic analog as the internal standard (IS), the cross-contribution (CC) phenomenon-contribution of IS to the intensities of the ions designating the analyte, and vice versa-has been demonstrated to affect the quantitation data. A novel approach based on the deviations of the empirically observed concentrations of a set of standards was developed to assess the accuracy of the empirically derived CC data. This approach demonstrated that normalization of ion intensities derived from the analyte and the IS generates reliable CC data. It further demonstrated that an ion-pair (designating the analyte and the IS) with ϳ5% or higher CC will result in a very limited linear calibration range. (J

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Instrumentation Analytical Parameters and Data Collection mentioning

confidence: 99%

Section: Graphic Presentation On the Evaluation Of CC Data Based On Tmentioning

confidence: 99%

See 2 more Smart Citations

A novel approach to evaluate the extent and the effect of cross-contribution to the intensity of ions designating the analyte and the internal standard in quantitative GC-MS analysis

Chen

Chang²,

Wang

et al. 2008

J. Am. Soc. Mass Spectrom.

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show abstract

“…In these cases, it is required that the analytes and the IS generate sufficiently separated peaks, and that derivatization of the analytes allows the elimination of the phenomenon of "cross-contribution", i.e. "contribution of the analyte and the IS to the intensities of ions designated for the IS and the analyte" (Chang et al, 2001). …”

Section: Derivatization Proceduresmentioning

confidence: 99%

Chromatographic Methodologies for Analysis of Cocaine and Its Metabolites in Biological Matrices

Valente¹,

Carvalho²,

Bastos³

et al. 2012

Gas Chromatography - Biochemicals, Narcotics and Essential Oils

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GC‐MS analysis of multiply derivatized opioids in urine

2007

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Opiates such as hydrocodone, hydromorphone, oxycodone, noroxycodone, and oxymorphone reportedly may interfere with the analysis of morphine and codeine. The analysis of these compounds themselves also is an important issue. Thus, double derivatization approaches utilizing methoxyamine and hydroxylamine to first form oxime products with keto-opiates, followed by the derivatization with trimethylsilyl (TMS) or propionyl groups, have been developed for the simultaneous analysis of these compounds. However, these studies have not included all compounds of interest and resulted in inadequate chromatographic resolution or significant intensity cross-contribution between the ions designating the analyte and its deuterated internal standard for certain compounds. By exploring three-step derivatization approaches with the combination of various derivatization groups and orders, this study concluded that application of methoxyimino/propionyl/TMS groups, in the order listed, facilitated the simultaneous analysis of eight opiates (morphine, 6-acetylmorphine, hydromorphone, oxymorphone, codeine, hydrocodone, oxycodone and noroxycodone) in urine samples, achieving satisfactory limits of quantitation and detection. In addition, the adapted approach resulted in two usable products for morphine and codeine providing alternatives, should interferences render any of these products non-usable.

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Isotopic analogs as internal standards for quantitative analyses by GC/MS — evaluation of cross-contribution to ions designated for the analyte and the isotopic internal standard

Cited by 20 publications

References 10 publications

A novel approach to evaluate the extent and the effect of cross-contribution to the intensity of ions designating the analyte and the internal standard in quantitative GC-MS analysis

A novel approach to evaluate the extent and the effect of cross-contribution to the intensity of ions designating the analyte and the internal standard in quantitative GC-MS analysis

Chromatographic Methodologies for Analysis of Cocaine and Its Metabolites in Biological Matrices

GC‐MS analysis of multiply derivatized opioids in urine

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