# Glossary¶

binding model
Set of parameters to model how a protein binds to chromatography resin beads. Common models include the Steric Mass Action (SMA) model, or the Langmuir model.
buffer
A set of chemical (s) in solution, defining the ion content in the chromatography column at the time of use. Unlike load solutions, buffers are assumed to not contain any of the product component (s) being separated.
chemical
Constituents of the solutions involved in the chromatography process. These include constituents of the buffers, as well as those of the load matrix. Examples include Sodium Acetate, or Acetic Acid.
column model
Model of a chromatography column, as provided by a column manufacturer, before any resin has been chosen or packed. Not to be confused with a packed column.
component
Charged species present in a chemical. Common examples include Sodium, or Acetate.
experiment
Collection of experimental data about an observed chromatography process. Experimental data includes information about the product purified, the column and system used, the process (or method) and output data as measured by the experimentalist(s): UV absorption, pH, conductivity, product component fractions, and more.
home directory
A location on the user’s file system, inside which is contained all user specific files needed by Reveal Chromatography. These are copied during installation and while in use. On both Windows 7 and Windows 10, it is located at C:\Users\<USERNAME>. See Uninstalling Reveal Chromatography for more details about where each type of file is.
initial buffer
The initial buffer of a simulation refers to the buffer the resin was equilibrated in before the first simulated step. For example, in a typical Gradient Elution experiment with a method made of Equil > Load > Wash > Gradient Elution, that buffer is the equilibration step buffer assuming that the simulation starts at the load step.
A set of chemical (s) and product component (s) in solution, defining the ion and product content at the time of use.
method
A succession of method step (s) to implement the complete experimental chromatography process, from the preparation of the column to the cleaning of the column.
method step
One of the steps of the chromatography process, each achieving a needed function for the best possible purification by injecting in the column one or two solutions at specific conditions (flow rate, volume of solution injected). Examples of steps include equilibration, load, wash, gradient elution, strip, etc.
packed column
Part of the chromatography apparatus made of a column type, packed to a certain height with resin beads to induce the separation of product component (s). Not to be confused with a column model.
percentile
A percentile is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations fall. For example, the 20th percentile is the value (or score) below which 20% of the observations may be found.
product
One or more variants of the target protein which is being purified. Each variant is called a product component.
product assay
An experimental technique used to measure the proportion and properties of solution constituents. Common examples include Ion Exchange HPLC (separating components based on charge), or mass spectrometry (separating components based on mass).
product component
One of the constituents of a process stream being purified. These include the target protein being purified, potential product isoforms, as well as potential process impurities. Their number and properties are defined by the product assay (s) used to evaluate product purity.
simulation
Simulating chromatography process through a specific chromatography apparatus and assuming a binding model a transport model for the target product to purify and a method. The results of a simulation include a description of the concentration of each product component over time in the column, the predicted UV absorption chromatogram, as well as other time series such as the predicted cation concentration.
study
Analysis of the chromatography purification of a product. A study uses a given chromatography setup, built from general user data, and specific study data. It can contain experiment (s), simulation (s), and analysis tools to model chromatography processes for the aforementioned product.
study data
Data elements specifically involved in the current study and used by experiments/simulations to explore the properties of a product. See also the user data for data elements that can be shared across studies.
transport model
A set of parameters to model the transport of protein in solution through a packed column during chromatography. The most standard model, which is assumed in Reveal Chromatography is the General Rate Model (GRM).
user data
Data elements that define products and system components and are used to set up a chromatography study, such as product, resins, column model, chromatography systems, etc. User data can be shared and reused across multiple studies, potentially studying different products. See also the study data for components that are specific to a study.