Product Ion Scan
Product Ion Scan - Related Videos
08:57
Focussed Ion Beam Milling and Scanning Electron Microscopy of Brain Tissue
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Cited by 105 •
2011
This protocol describes how resin embedded brain tissue can be prepared and imaged in the three dimensions in the focussed ion beam, scanning electron microscope.
01:21
Focused Ion Beam Scanning Electron Microscopy for 3D Reconstruction of Synaptically Linked Neurons
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2025
Take a fixed section of mouse cortical brain tissue exhibiting neuronal axons and dendrites. The dendrites possess protrusions, known as dendritic spines, which form synapses with axons.Incubate the tissue with osmium-ferrocyanide, which binds to lipids, followed by another osmium application, which enhances structural contrast for imaging.Stain with a heavy metal compound that binds to macromolecules and enhances contrast.Dehydrate using increasing alcohol concentrations for resin...
03:24
Common Ion Effect
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2020
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Châtelier’s principle. Consider the dissolution of silver iodide: This solubility equilibrium may be shifted left by the addition of either silver(I) or iodide ions, resulting in...
03:11
Precipitation of Ions
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2020
Predicting Precipitation The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is: It is important to realize that this equilibrium is established in any aqueous solution containing Ca2+ and CO32– ions, not just in a solution formed by saturating water with calcium carbonate. Consider, for example, mixing aqueous solutions of the soluble compounds sodium carbonate and calcium nitrate. If the concentrations of calcium and carbonate ions in the mixture...
02:28
Leaky Scanning
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2020
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
FAQs
First, the instrument isolates a precursor ion from the ions present in the experiment. It then accelerates that selected ion into a collision gas, where collision-induced dissociation produces product ions. Measuring those ions by their mass-to-charge ratios converts the fragmentation event into a spectrum that can be interpreted for the selected precursor.
The product-ion spectrum records which fragment ions arise from the selected precursor and their mass-to-charge ratios. This pattern acts as a structural fingerprint, giving analysts information that supports compound identification and structural elucidation. It can also help confirm molecular composition when the observed fragments are consistent with the compound being examined.
Precursor-ion selection focuses the measurement on one ion before fragmentation occurs. The resulting product ions can therefore be related specifically to that selected precursor rather than considered as an undifferentiated mixture. This focused relationship supports interpretation of fragmentation patterns and makes the scan useful for confirming compounds in analytical chemistry.
A typical workflow begins by selecting and isolating a precursor ion. The instrument accelerates it into a collision gas to induce collision-induced dissociation, then measures the generated product ions according to their mass-to-charge ratios. Analysts examine the resulting product-ion spectrum as a fragmentation pattern for identification, structural interpretation, or composition confirmation.
The scan reveals which product ions are generated from a chosen precursor ion. Analysts can use these precursor-to-product ion relationships to develop selective multiple-reaction-monitoring transitions. Those transitions support detection and quantification of target compounds, particularly when the targets occur in complex samples where selective measurement is important.
Product Ion Scan measurements are useful when analysts need more than a precursor-ion signal to characterize a compound. The fragment pattern can support compound identification, structural elucidation, and confirmation of molecular composition. In complex samples, the same information also contributes to selective detection and quantification strategies for target compounds.