Chromatography

Yes, Crime Scene Investigators use chromatography to analyze and identify substances found at crime scenes. Chromatography helps separate and detect chemical compounds in a sample, such as drugs or accelerants, aiding in the investigation and solving of crimes.

Members of a homologous series may have similar chemical properties due to their structural similarity, making it difficult to separate them by thin layer chromatography. However, slight differences in molecular size or functional groups could potentially allow for separation through careful selection of the chromatography conditions. Additional techniques such as column chromatography or high-performance liquid chromatography may be more suitable for separating homologous compounds.

Paper chromatography is a technique used to separate and identify mixtures of substances based on their different migration rates through a porous paper strip. It works on the principle of differential affinity of the components for the stationary phase (paper) and mobile phase (solvent). The separated components can be visualized by developing the paper in a suitable solution and observing the distinct bands or spots they form.

Analytical chromatography refers to the processes of separating a sample into its components and identifying these components, and is usually a small scale process. Preparative chromatography, on the other hand deals with isolating the separated components of a sample, and can be done on both small-scale or larger industrial scale operations. Preparative chromatography is a form of purification that utilizes chromatography.

Chromatography works to separate particles of ink by exploiting differences in solubility between the ink components and the mobile phase (solvent). As the mobile phase moves through the stationary phase (usually a paper or column), it carries the ink components at different rates based on their solubility. This differential movement results in separation of the ink particles into distinct bands or spots on the chromatography paper.

Candy chromatography was not discovered by one specific individual. It is a scientific technique that involves separating and identifying different components in candy dyes through a process similar to traditional chromatography.

Two industries that use chromatography are pharmaceuticals and environmental testing. In pharmaceuticals, chromatography is used for drug development and quality control. In environmental testing, chromatography helps analyze pollutants in air, water, and soil.

Chromatography was first used to solve crimes in the early 20th century, around the 1920s. This technique allowed for the separation and identification of different components in complex mixtures, such as chemical substances found at crime scenes.

Size-exclusion chromatography (SEC) is also known as gel permeation chromatography (GPC) or gel filtration chromatography and separates molecules according to their size (or more accurately according to their hydrodynamic diameter or hydrodynamic volume). Smaller molecules are able to enter the pores of the media and, therefore, molecules are trapped and removed from the flow of the mobile phase. The average residence time in the pores depends upon the effective size of the analyte molecules. However, molecules that are larger than the average pore size of the packing are excluded and thus suffer essentially no retention; such species are the first to be eluted. It is generally a low-resolution chromatography technique and thus it is often reserved for the final, "polishing" step of a purification. It is also useful for determining the tertiary structure and quaternary structure of purified proteins, especially since it can be carried out under native solution conditions. An expanded bed chromatographic adsorption (EBA) column for a biochemical separation process comprises a pressure equalization liquid distributor having a self-cleaning function below a porous blocking sieve plate at the bottom of the expanded bed, an upper part nozzle assembly having a backflush cleaning function at the top of the expanded bed, a better distribution of the feedstock liquor added into the expanded bed ensuring that the fluid passed through the expanded bed layer displays a state of piston flow. The expanded bed layer displays a state of piston flow. The expanded bed chromatographic separation column has advantages of increasing the separation efficiency of the expanded bed. Expanded-bed adsorption (EBA) chromatography is a convenient and effective technique for the capture of proteins directly from unclarified crude sample. In EBA chromatography, the settled bed is first expanded by upward flow of equilibration buffer. The crude feed, a mixture of soluble proteins, contaminants, cells, and cell debris, is then passed upward through the expanded bed. Target proteins are captured on the adsorbent, while particulates and contaminants pass through. A change to elution buffer while maintaining upward flow results in desorption of the target protein in expanded-bed mode. Alternatively, if the flow is reversed, the adsorbed particles will quickly settle and the proteins can be desorbed by an elution buffer. The mode used for elution (expanded-bed versus settled-bed) depends on the characteristics of the feed. After elution, the adsorbent is cleaned with a predefined cleaning-in-place (CIP) solution, with cleaning followed by either column regeneration (for further use) or storage. Reversed-phase chromatography (RPC) is any liquid chromatography procedure in which the mobile phase is significantly more polar than the stationary phase. It is so named because in normal-phase liquid chromatography, the mobile phase is significantly less polar than the stationary phase. Hydrophobic molecules in the mobile phase tend to adsorb to the relatively hydrophobic stationary phase. Hydrophilic molecules in the mobile phase will tend to elute first. Separating columns typically comprise a C8 or C18 carbon-chain bonded to a silica particle substrate. Hydrophobic interactions between proteins and the chromatographic matrix can be exploited to purify proteins. In hydrophobic interaction chromatography the matrix material is lightly substituted with hydrophobic groups. These groups can range from methyl, ethyl, propyl, octyl, or phenyl groups. At high salt concentrations, non-polar sidechains on the surface on proteins "interact" with the hydrophobic groups; that is, both types of groups are excluded by the polar solvent (hydrophobic effects are augmented by increased ionic strength). Thus, the sample is applied to the column in a buffer which is highly polar. The eluant is typically an aqueous buffer with decreasing salt concentrations, increasing concentrations of detergent (which disrupts hydrophobic interactions), or changes in pH. In general, Hydrophobic Interaction Chromatography (HIC) is advantageous if the sample is sensitive to pH change or harsh solvents typically used in other types of chromatography but not high salt concentrations. Commonly, it is the amount of salt in the buffer which is varied. In 2012, Müller and Franzreb described the effects of temperature on HIC using Bovine Serum Albumin (BSA) with four different types of hydrophobic resin. The study altered temperature as to effect the binding affinity of BSA onto the matrix. It was concluded that cycling temperature from 50 to 10 degrees would not be adequate to effectively wash all BSA from the matrix but could be very effective if the column would only be used a few times. Using temperature to effect change allows labs to cut costs on buying salt and saves money. If high salt concentrations along with temperature fluctuations want to be avoided you can use a more hydrophobic to compete with your sample to elute it. [source] This so-called salt independent method of HIC showed a direct isolation of Human Immunoglobulin G (IgG) from serum with satisfactory yield and used Beta-cyclodextrin as a competitor to displace IgG from the matrix. This largely opens up the possibility of using HIC with samples which are salt sensitive as we know high salt concentrations precipitate proteins. Hydrodynamic chromatography (HDC) is derived from the observed phenomenon that large droplets move faster than small ones. In a column, this happens because the center of mass of larger droplets is prevented from being as close to the sides of the column as smaller droplets because of their larger overall size. Larger droplets will elute first from the middle of the column while smaller droplets stick to the sides of the column and elute last. This form of chromatography is useful for separating analytes by molar mass, size, shape, and structure when used in conjunction with light scattering detectors, viscometers, and refractometers. The two main types of HDC are open tube and packed column. Open tube offers rapid separation times for small particles, whereas packed column HDC can increase resolution and is better suited for particles with an average molecular mass larger than 10 5 {\displaystyle 10^{5}} daltons. HDC differs from other types of chromatography because the separation only takes place in the interstitial volume, which is the volume surrounding and in between particles in a packed column.HDC shares the same order of elution as Size Exclusion Chromatography (SEC) but the two processes still vary in many ways. In a study comparing the two types of separation, Isenberg, Brewer, Côté, and Striegel use both methods for polysaccharide characterization and conclude that HDC coupled with multiangle light scattering (MALS) achieves more accurate molar mass distribution when compared to off-line MALS than SEC in significantly less time. This is largely due to SEC being a more destructive technique because of the pores in the column degrading the analyte during separation, which tends to impact the mass distribution. However, the main disadvantage of HDC is low resolution of analyte peaks, which makes SEC a more viable option when used with chemicals that are not easily degradable and where rapid elution is not important. HDC plays an especially important role in the field of microfluidics. The first successful apparatus for HDC-on-a-chip system was proposed by Chmela, et al. in 2002. Their design was able to achieve separations using an 80 mm long channel on the timescale of 3 minutes for particles with diameters ranging from 26 to 110 nm, but the authors expressed a need to improve the retention and dispersion parameters. In a 2010 publication by Jellema, Markesteijn, Westerweel, and Verpoorte, implementing HDC with a recirculating bidirectional flow resulted in high resolution, size based separation with only a 3 mm long channel. Having such a short channel and high resolution was viewed as especially impressive considering that previous studies used channels that were 80 mm in length. For a biological application, in 2007, Huh, et al. proposed a microfluidic sorting device based on HDC and gravity, which was useful for preventing potentially dangerous particles with diameter larger than 6 microns from entering the bloodstream when injecting contrast agents in ultrasounds

im no expert but loss on drying refers to weight of mass after you dried something and then take that amount away from the pre died weight (so you have to know the initial weight) for residue on ignition are we still talking weight ? if so fire up the dry matter and then weigh wat you got left buddy

Loss on drying means at a define temp.how much volatile matter driven off form your sample means after ending the test you will get the sample without moisture and volatile matter but in residue on ignetion all part of organic matter will removed and only inorganic matter will present because we are finding how much inorganic impurity present in your sample (Dhiraj K.Thakur Abbott Healthcare)

Chromatography is used for many purposes. Generally, it can be used to determine the elements which are mixed in the mixture where the mixture must be in in liquid and able to dissolve in the solvent ethanol. It is mainly used in determining the different substances used in food dyes.

In science, chromatography is typically performed by passing a mixture of substances through a stationary phase using a mobile phase. As the substances travel through the stationary phase, they separate based on their differing affinities to the stationary and mobile phases. This separation allows scientists to analyze and identify the individual components of the mixture.

Methanol is a commonly used solvent in paper chromatography because of its polarity and ability to dissolve a wide range of compounds. It is especially good for separating polar compounds. However, caution should be taken as methanol is also toxic and flammable.

Yes, the polarity of a solvent mixture can affect the completeness of the separation in chromatography. A more polar solvent mixture will tend to separate compounds with different polarities more effectively, leading to better resolution in the chromatogram. However, if the solvent mixture is too polar, it may cause poor separation or elution of certain compounds, affecting the completeness of the separation.

Chromatography comes from the Greek chrom- meaning "colored" and graph- meaning "writing" so it literally means "colored writing".

If paper chromatography is left in the solution, the solvent will continue to move up the paper by capillary action. This can lead to the separation of the components in the mixture to a greater extent. Additionally, the colors may spread out and further separate along the paper.

GCMS involves running the sample through a mass spectrometer following the data received from chromatography. MS fragments the analytes to show patterns specific to the analyte (and the ionization technique and sector powers) therefore allowing the analyte to be identified. GC is used to separate all volatile substituents of a sample so they can be identified one by one.

Chromatography allows us to separate and analyze different components in a mixture based on their differential affinities for a stationary phase and a mobile phase. This technique is widely used in various fields such as chemistry, biochemistry, and forensic science for identifying and quantifying the components of complex mixtures.

Chromatography is a physical change because even though you are separating colors the original atomic identity of the colored ink being separated is still retained showing that a chemical reaction has not taken place.

Yes, there are risks associated with chromatography. These can include exposure to harmful chemicals, inhalation of fumes, and potential fire hazards. It is important to follow proper safety procedures and use necessary protective equipment when conducting chromatography experiments.

The abilities of the compounds to absorb and their solubility are the physical properties used in the separation of components via chromatography. Boiling points are not typically used in chromatography, as the separation technique relies more on differences in absorption and solubility to separate compounds.

Keeping a small spot on TLC will allow for greater resolution between the spots allowing for more accurate Rf calculations and solvent separation/preparation if used to isolate a compound in a mixture.

Pen chromatography is a simple paper chromatography technique where a capillary pen is used to apply a small sample to filter paper. As the solvent moves up the paper, different components in the sample will separate into distinct bands based on their interactions with the paper and the solvent. This technique is often used for separating and identifying components of a mixture.

Molecular exclusion chromatography is a type of size exclusion chromatography that separates molecules based on their size and shape. It works by passing a sample mixture through a porous stationary phase, where smaller molecules are able to enter the pores and take longer to elute, while larger molecules pass more easily through the column and elute faster. This technique is commonly used for separating proteins and nucleic acids.

The Rf value, or retention factor, in chromatography is a measure of how far a compound travels in relation to the solvent front in a chromatogram. It helps in identifying and characterizing compounds based on their movement and separation in the chromatographic system. Comparing Rf values can aid in qualitative analysis, determination of purity, and identification of unknown components within a sample.