Glowmatography is a laboratory technique for the separation of

dye Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy Fantasy is a genre of speculative fiction that involves supernatural or Magic (supernatural), magical ele ...

s present in solutions contained in

glow stick A glow stick, also known as a light stick, chem light, light wand, light rod, and rave light, is a self-contained, short-term light-source. It consists of a translucent plastic tube containing isolated substances that, when combined, make light ...

s. The chemical components of such solutions can be chromatographically separated into

polar Polar may refer to: Geography * Geographical pole, either of the two points on Earth where its axis of rotation intersects its surface ** Polar climate, the climate common in polar regions ** Polar regions of Earth, locations within the polar circ ...

and

nonpolar In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end. Polar molecules must contain one or more polar ...

components. Developed as a laboratory class experiment, it can be used to demonstrate chemistry concepts of polarity,

chemical kinetics Chemical kinetics, also known as reaction kinetics, is the branch of physical chemistry that is concerned with understanding the rates of chemical reactions. It is different from chemical thermodynamics, which deals with the direction in which a ...

, and

chemiluminescence Chemiluminescence (also chemoluminescence) is the emission of light (luminescence) as the result of a chemical reaction, i.e. a chemical reaction results in a flash or glow of light. A standard example of chemiluminescence in the laboratory se ...

Description

In the chromatography of a glow stick solution, a piece of

chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Ch ...

, a highly

substance, is used as the stationary phase while comparatively less-polar solvents like

acetone Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ...

and 91%

isopropyl alcohol Isopropyl alcohol (IUPAC name propan-2-ol and also called isopropanol or 2-propanol) is a colorless, flammable, organic compound with a pungent alcoholic odor. Isopropyl alcohol, an organic polar molecule, is miscible in water, ethanol, an ...

can be used as the

mobile phase In analytical and organic chemistry, elution is the process of extracting one material from another by washing with a solvent: washing of loaded ion-exchange resins to remove captured ions, or eluting proteins or other biopolymers from an el ...

. Chalk is made up of

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

(CaCO₃) or

calcium sulfate Calcium sulfate (or calcium sulphate) is an inorganic salt with the chemical formula . It occurs in several hydrated forms; the anhydrous state (known as anhydrite) is a white crystalline solid often found in evaporite deposits. Its dihydrate fo ...

(CaSO₄), and therefore contains ions. This allows it to attract other

ions An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

and

polar molecules In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end. Polar molecules must contain one or more polar ...

, but not nonpolar molecules. As a result, ionic and more-polar dyes would be attracted to the stationary phase and move relatively slowly or a fairly small distance, while less polar dyes would migrate further as the mobile phase wicks up the chalk. This then allows for the separation of dyes.

Experiment

This experiment can be conducted with glow sticks, chalks, and solutions of acetone or isopropyl alcohol. Drops of glowing fluid from a glow stick are added to a chalk so that a band is created halfway through it. The chalk is then placed vertically into a beaker filled with a small amount of acetone or alcohol - ensuring the surface of the solvent is below the dye band. The liquid is then allowed to travel up the chalk; polar dyes would tend to stick to the chalk and not travel significantly while non-polar dyes would travel up with the solvent. Once it travels almost to the top of the chalk, it is removed from the beaker. The chalk

chromatogram In chemical analysis, chromatography is a laboratory technique for the Separation process, separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it ...

, with separation of colours, can then be observed in a dark room. Additionally, this glomatographic experiment can be done using other materials. For instance,

silica gel Silica gel is an amorphous and porosity, porous form of silicon dioxide (silica), consisting of an irregular three-dimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. The voids may contain wate ...

can be used as the stationary phase together with a solution of nonpolar

hexanes The molecular formula C6H14 (molar mass: 86.17 g/mol) may refer to: * Dimethylbutanes ** 2,2-Dimethylbutane ** 2,3-Dimethylbutane * Hexane Hexane () or ''n''-hexane is an organic compound, a straight-chain alkane with six carbon atoms and t ...

acting as the mobile phase. The polar components would be attracted to the polar

silanol A silanol is a functional group in silicon chemistry with the connectivity Si–O–H. It is related to the hydroxy functional group (C–O–H) found in all alcohols. Silanols are often invoked as intermediates in organosilicon c ...

(Si-OH) groups on the surface of the silica gel, and the nonpolar components would travel further with the hexanes. Further, dyes in glow sticks can also be extracted using

liquid carbon dioxide Liquid carbon dioxide is the liquid state of carbon dioxide (), which cannot occur under atmospheric pressure. It can only exist at a pressure above , under (temperature of critical point) and above (temperature of triple point). Low-temperatu ...

(CO₂) as an environmentally friendly or

green solvent Green solvents are environmentally friendly chemical solvents that are used as a part of green chemistry. They came to prominence in 2015, when the United Nations, UN defined a new Sustainability measurement, sustainability-focused development pl ...

. In this case, non polar dyes would dissolve in the liquid CO₂ and other dyes would be attracted to cotton.

References

External links

{{commonscat, Glowmatography Chemistry classroom experiments Chromatography

Description

Experiment

See also

References

External links