Chromatography
Chromatography is a chemical separation technique that is commonly applied in chemical analysis. This analytical process/method can be applied to in many various experiments. It is known for its efficiency and versatility. Chromatography can divide substances into is most basic components in a single step and at the same time give a rough estimation of the quantity of each part. This technique is applied on samples of liquid, solid or gaseous nature.
HPLC (High Performance Liquid Chromatography) is a column chromatography method used to separate and identify compounds in a given solvent sample. The solvent is forced through high pressure in a column chromatograph. This allows a very small particle size, which gives a greater surface area for phase interactions.
GLC (Gas-liquid Chromatography) is usually used in organic chemistry works, in separating gaseous and volatile substances. It tests the purity of a substance.
TLC (Thin Layer Chromatography) on the other hand, is a type of liquid chromatography. It separates different structured chemical compounds according to the rate at which these compounds move. In turn, it identifies the different compounds present.
Resolution is used to measure the purity of the substances. A resolution of a chromatography system measures the separation between two peaks on a graph. The better the resolution, the better the purity of the separated components. In relation to the GM rice, chromatography will be able to break down the system to allow easy identification of the different building components that make up the product. From there, it can be determined if the GM food product is safe for consumption with no particularly harmful effects on the human body.
Atomic Absorption spectroscopy (AA spectroscopy)
During production and processing of food, trace elements and their counterparts are most likely incorporated into the system. This is a crucial problem as even traces of metals, for example, can result in a toxic food product. AA spectroscopy is a method used to detect the presence of trace elements such as metal, in a given sample. This process involves the absorption of light by the metals. The sample is first vaporized, and the vapor that results contains free atoms of the particular element. Light is then shined and the atoms present get agitated and absorb the light. As such, the intensity is lowered and hence will compute to a higher or lower absorbance value respective to the experiment conducted. As concentration goes up, so does the absorbance. By applying AA spectroscopy to our product, trace elements of metals can be detected, should they be present. In turn, we will then similarly be able to determine the safety of the product to our consumers.
LD50
In the measurement of toxicity in chemicals, LD50 is used as a form or measurement. LD50 stands for Lethal Dose-50%. This refers to the dose that would essentially kill 50% of the population tested. It is expressed in milligrams of material per kilogram of subject’s body weight.
Generally, the higher the LD50 value, the less toxic the substance is to the body, Vice versa.
For example, with reference to testing on a population of rats, the LD50 value of cane sugar is 29700 mg/kg. This means that it takes 29700mg/kg of cane sugar to kill 50% of the population on rats tested. However, it only takes 192mg/kg of caffeine to have the same effect.
Hence, caffeine has a higher toxicity value in comparison to cane sugar.
Similarly, the LD50 value of our GM rice will determine its toxicity.
Dose-response curve
The dose-response curve correlates to exposure of a substance and its induced effects.
With this dose-response curve, we can not only determine lowest amount of material that causes the effect, we can also find out the actual effect the respective chemical has on the subject and also determine the rate at which the effect takes place.
Below is an illustration of LD50 of 20mg/kg and how it comes about in relationship with the dose-response curve.
(picture will be posted later).
Dose-response curve Ld50 value of 20mg/kg.
Image from: "Dose-response relationship." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland
author of research: Sutha
help to post: monica
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