Abstract: In mass spectrometry significant error is introduced during sample preparation (sample-to-sample error), during ion generation (ion suppression), and during ion transmission (ion transmission losses). We demonstrate the ability to correct for ion suppression and ion transmission losses, and that once corrected for ion losses, a sample-to-sample normalization of the analytical sample to the internal standard is possible. By normalizing to a standard sample the analytical sample becomes completely comparable to any similarly treated sample.

Abstract: In mass spectrometry significant error is introduced during sample preparation (sample-to-sample error), during ion generation (ion suppression), and during ion transmission (ion transmission losses). We demonstrate the ability to correct for ion suppression and ion transmission losses, and that once corrected for ion losses, a sample-to-sample normalization of the analytical sample to the internal standard is possible. By normalizing to a standard sample the analytical sample becomes completely comparable to any similarly treated sample.

Abstract: In mass spectrometry significant error is introduced during sample preparation (sample-to-sample error), during ion generation (ion suppression), and during ion transmission (ion transmission losses). We demonstrate the ability to correct for ion suppression and ion transmission losses, and that once corrected for ion losses, a sample-to-sample normalization of the analytical sample to the internal standard is possible. By normalizing to a standard sample the analytical sample becomes completely comparable to any similarly treated sample.

Abstract: A method for assaying phenotypic similarity or dissimilarity between organisms is disclosed in which a composite sample of admixed first and second samples is provided. The first, standard sample contains average concentrations of compounds of molecular mass less than about 1000 AMU present in the organism species. The second, assay sample contains compounds of having a similar molecular mass present in the organism whose phenotype is to be assayed. The constituents of both samples are (i) in a liquid medium and (ii) each compound of a sample has the same, first and second respective amounts of first and second stable isotopes of a first atom. The composite sample is mass spectroscopically analyzed for analytes, with the ratio of first to second isotope being determined for each analyte, along with a composite sample median ratio. The ratios for each analyte are compared to the median, with outlying ratios indicating dissimilarity.

Abstract: A method for identifying a biological analyte that is affected by a stressor is disclosed in which two substantially identical biological samples are provided, with a first sample being a control sample and a second sample being an experimental sample. The control sample is grown with a nutrient having an isotope of a first atom, whereas the experimental sample is grown with a nutrient having a second isotope of the first atom. The experimental sample is grown with a stressing agent and regimen. The samples are admixed, and the formed composite is mass spectroscopically assayed for analyte peaks. The ratio of first isotope to second isotope is determined for the peaks, as is a sample median isotopic ratio. The ratio for assayed analyte peaks is compared with the median ratio. An analyte whose isotopic ratio significantly deviates from the median ratio is an analyte affected by the stressing agent.

Abstract: A method for identifying a biological analyte that is affected by a stressor is disclosed in which two substantially identical biological samples are provided, with a first sample being a control sample and a second sample being an experimental sample. The control sample is grown with a nutrient having an isotope of a first atom, whereas the experimental sample is grown with a nutrient having a second isotope of the first atom. The experimental sample is grown with a stressing agent and regimen. The samples are admixed, and the formed composite is mass spectroscopically assayed for analyte peaks. The ratio of first isotope to second isotope is determined for the peaks, as is a sample median isotopic ratio. The ratio for assayed analyte peaks is compared with the median ratio. An analyte whose isotopic ratio significantly deviates from the median ratio is an analyte affected by the stressing agent.

Abstract: A method for identifying a biological analyte that is affected by a stressor is disclosed in which two substantially identical biological samples are provided, with a first sample being a control sample and a second sample being an experimental sample. The control sample is grown with a nutrient having an isotope of a first atom, whereas the experimental sample is grown with a nutrient having a second isotope of the first atom. The experimental sample is grown with a stressing agent and regimen. The samples are admixed, and the formed composite is mass spectroscopically assayed for analyte peaks. The ratio of first isotope to second isotope is determined for the peaks, as is a sample median isotopic ratio. The ratio for assayed analyte peaks is compared with the median ratio. An analyte whose isotopic ratio significantly deviates from the median ratio is an analyte affected by the stressing agent.

Abstract: A method for identifying a biological analyte that is affected by a stressor is disclosed in which two substantially identical biological samples are provided, with a first sample being a control sample and a second sample being an experimental sample. The control sample is grown with a nutrient having an isotope of a first atom, whereas the experimental sample is grown with a nutrient having a second isotope of the first atom. The experimental sample is grown with a stressing agent and regimen. The samples are admixed, and the formed composite is mass spectroscopically assayed for analyte peaks. The ratio of first isotope to second isotope is determined for the peaks, as is a sample median isotopic ratio. The ratio for assayed analyte peaks is compared with the median ratio. An analyte whose isotopic ratio significantly deviates from the median ratio is an analyte affected by the stressing agent.

Abstract: A method for identifying a biological analyte that is affected by a stressor is disclosed in which two substantially identical biological samples are provided, with a first sample being a control sample and a second sample being an experimental sample. The control sample is grown with a nutrient having an isotope of a first atom, whereas the experimental sample is grown with a nutrient having a second isotope of the first atom. The experimental sample is grown with a stressing agent and regimen. The samples are admixed, and the formed composite is mass spectroscopically assayed for analyte peaks. The ratio of first isotope to second isotope is determined for the peaks, as is a sample median isotopic ratio. The ratio for assayed analyte peaks is compared with the median ratio. An analyte whose isotopic ratio significantly deviates from the median ratio is an analyte affected by the stressing agent.

Abstract: A composition adapted for mass spectral analysis is disclosed as are methods of its use in mass spectral analyses. A contemplated composition contains a mass spectrally-determinable amount of each of (i) at least one analyte to be assayed and (ii) a standard compound. Each of the molecules of the standard compound contains one or the other of a pair of two stable isotopes of the same element that differ in molecular weight by at least two atomic mass units. Those two isotopes are present in the molecules of the standard compound in a predetermined ratio that is other than the naturally occurring ratio of those isotopes.

Abstract: A method for assaying phenotypic similarity or dissimilarity between organisms is disclosed in which a composite sample of admixed first and second samples is provided. The first, standard sample contains average concentrations of compounds of molecular mass less than about 1000 AMU present in the organism species. The second, assay sample contains compounds of having a similar molecular mass present in the organism whose phenotype is to be assayed. The constituents of both samples are (i) in a liquid medium and (ii) each compound of a sample has the same, first and second respective amounts of first and second stable isotopes of a first atom. The composite sample is mass spectroscopically analyzed for analytes, with the ratio of first to second isotope being determined for each analyte, along with a composite sample median ratio. The ratios for each analyte are compared to the median, with outlying ratios indicating dissimilarity.

Abstract: A composition adapted for mass spectral analysis is disclosed as are methods of its use in mass spectral analyses. A contemplated composition contains a mass spectrally-determinable amount of each of (i) at least one analyte to be assayed and (ii) a standard compound. Each of the molecules of the standard compound contains one or the other of a pair of two stable isotopes of the same element that differ in molecular weight by at least two atomic mass units. Those two isotopes are present in the molecules of the standard compound in a predetermined ratio that is other than the naturally occurring ratio of those isotopes.

Abstract: A method for identifying a biological analyte that is affected by a stressor is disclosed in which two substantially identical biological samples are provided, with a first sample being a control sample and a second sample being an experimental sample. The control sample is grown with a nutrient having an isotope of a first atom, whereas the experimental sample is grown with a nutrient having a second isotope of the first atom. The experimental sample is grown with a stressing agent and regimen. The samples are admixed, and the formed composite is mass spectroscopically assayed for analyte peaks. The ratio of first isotope to second isotope is determined for the peaks, as is a sample median isotopic ratio. The ratio for assayed analyte peaks is compared with the median ratio. An analyte whose isotopic ratio significantly deviates from the median ratio is an analyte affected by the stressing agent.