High Mass Measurements
High Mass Measurements - Related Videos
08:00
Measuring Mass in the Laboratory
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2023
The analytical balance is the common piece of equipment in the scientific laboratory. These highly precise instruments can measure down to ten thousandths or even hundred thousandths of a gram. The triple beam balance is a type of scale that uses counterweights on a three rider beams to counterbalance the sample in the pan. On the other hand, modern analytical balances use a complex system of electronic sensors to accurately mass a substance. The analytical balance is so sensitive that it...
13:35
Mass Conservation and Flow Rate Measurements
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2023
Source: Ricardo Mejia-Alvarez and Hussam Hikmat Jabbar, Department of Mechanical Engineering, Michigan State University, East Lansing, MI The purpose of this experiment is to demonstrate the calibration of a flow passage as a flowmeter using a control volume (CV) formulation [1, 2]. The CV analysis focuses on the macroscopic effect of flow on engineering systems, rather than the detailed description that could be achieved with a detailed differential analysis. These two techniques should be...
01:52
Atomic Mass
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2020
Atoms — and the protons, neutrons, and electrons that compose them — are extremely small. For example, a carbon atom weighs less than 2 × 10−23 g. When describing the properties of tiny objects such as atoms, we use appropriately small units of measure, such as the atomic mass unit (amu). The amu was originally defined based on hydrogen, the lightest element, then later in terms of oxygen. Since 1961, it has been defined with regard to the most abundant isotope of carbon, atoms of which are...
01:54
Molar Mass
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2020
The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, water, H2O, and hydrogen peroxide, H2O2, are alike in that their respective molecules are composed of hydrogen and oxygen atoms. However, because a hydrogen peroxide molecule contains two oxygen atoms, as opposed to the water molecule, which has only one, the two substances exhibit very different properties. Atoms and molecules are extremely...
10:23
Lipid Droplet Isolation for Quantitative Mass Spectrometry Analysis
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Cited by 7 •
2017
Lipid droplets are important organelles for the replication of several pathogens, including the Hepatitis C Virus (HCV). We describe a method to isolate lipid droplets for quantitative mass spectrometry of associated proteins; it can be used under a variety of conditions, such as virus infection, environmental stress, or drug treatment.
FAQs
The charge-state distribution is central because the instrument records mass-to-charge ratios rather than molecular mass directly. Multiple observed charge states provide a pattern from which the mass of a protein or assembly can be calculated. This approach is especially useful for large biomolecules, where interpreting the distribution yields a consistent molecular-mass value despite different charge states.
Gentle electrospray ionization transfers proteins and complexes into the gas phase while preserving many noncovalent interactions. Maintaining these interactions helps the measured species retain aspects of its assembled state during analysis. As a result, the measurement can provide information about oligomerization, complex composition, and molecular organization rather than only the masses of isolated components.
A measured mass can help distinguish the components and stoichiometry of a molecular assembly, meaning the number and proportions of its associated subunits. Comparing the result with expected molecular arrangements can provide insight into oligomerization and complex organization. These observations connect the measured mass with structural and functional questions about how biomolecules associate.
The workflow begins by using gentle electrospray ionization to transfer a protein or molecular complex into the gas phase. The instrument then measures the mass-to-charge ratios of the resulting ions. Analysts examine the charge-state distribution and use it to calculate molecular mass, which can subsequently be interpreted for composition, stoichiometry, or assembly state.
They are useful when researchers need to characterize oligomerization, protein complexes, or biomolecular interactions. The measurements can connect molecular mass with the composition and organization of assemblies, supporting structural and functional studies. They also provide a way to examine how molecular assemblies behave under different conditions, making them relevant to investigations of biomolecular state and interaction.
High mass measurements can contribute to biologics quality assessment by characterizing the molecular mass and assembly state of biomolecules. Information about composition, oligomerization, and protein complexes may help identify whether the material has the expected organization. Because assemblies can change under different conditions, comparing measurements across conditions can also support evaluation of molecular-state changes.