A long time ago, scientists wanted to measure the degree of acidity of a substance, so they developed the concept of pH. The pH (with the "p" in lowercase) is a scale that helps us measure whether one substance is more acidic than another and vice versa. pH means hydrogen potential. The pH is a simplified scale of measurement, which indicates the acidity or alkalinity of a solution. Acidity and alkalinity are two extremes that describe chemical properties. Mixing acids with bases can cancel or neutralize their extreme effects. A substance that is not acidic or basic (or alkaline) is neutral.

Normally the pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acid can burn us. A pH greater than 7 is basic or alkaline, can dissolve the meat. It has been determined that the pH of moist skin is around 5.5 so if we apply some cream or soap with a lower or higher pH could cause irritation or burn. If it were a pH greater than 10 or less than 3, the skin could dissolve, causing great damage. Knowing the pH of the substances is very important for our safety against any chemical product.

Pure water has a neutral pH, that is, 7. When it is mixed with other chemicals, it becomes acidic or alkaline.

The food impact the pH of our body. The pH of our stomach is 1.4 due to the acid HCL that it contains, and which is useful for breaking down food. Some foods and their combinations can cause the stomach to generate more acid. If this happens very frequently, the acid could perforate the stomach causing an ulcer. Too much acid in the stomach could escape into the esophagus and reach your mouth. This unpleasant sensation is known as heartburn, means that you must consider the foods you eat.

The pH of soil moisture affects the availability of nutrients for plants. Many plants prefer a slightly acidic soil (pH between 4.5 and 5.5), while others prefer a less acid soil (pH between 6.5 and 7). Highly acid soils (with a pH lower than 4.5) reach concentrations of chemical elements toxic to plants.

The pH of the water affects terrestrial and aquatic life. Water from healthy lakes, ponds and rivers generally has a pH between 6 and 8. Most fish tolerate water with a pH between 6 and 9. More robust and strong fish usually die at lower and higher pH. Toads and other amphibians are more sensitive to pH than many fish.

The pH can help us to know when a substance is very dangerous for life.

The pH of saliva in your mouth, after brushing your teeth, should be around 7. That is, a neutral pH, which does not cause any damage to your teeth. If the pH is below 5.5, the enamel begins to be lost doing damage. If you eat a carbohydrate, such as bread or something that contains sugar, it will have the conditions to do more damage to your teeth. The pH balance (alkalinity versus acidity) of saliva normally varies between 6.2 and 7.4, with higher pH levels that are frequently observed during an increase in saliva secretion, for example, when smelling a meal is cooked or when you have an appetite and you see pictures of food.

One of the factors most related to the formation of stones in the kidney are changes in the level of urinary pH, because they influence the solubility and crystallization of the different components present in the urine. If the urine is alkaline (with a pH value higher than 6.2), present, for example, in cases of infection of the urinary tract, it will favor the formation of phosphate stones (calcium or struvite) and calcium oxalate. . On the contrary, if the urine contains a high level of acidity (with a pH value lower than 5.5), it will favor the appearance of uric acid, cystine and calcium oxalate stones. To avoid the formation or to reappear for the second time, it is recommended to keep a very strict control of the urinary pH to maintain it at optimum levels of safety, which would be to maintain the pH of the urine between 5.5 and 6.2.

How is the pH measured?

The pH of a substance can be measured by the colorimetric or potentiometric method. The Potentiometric is no more than the measurement with a pH electrode, it contacts with the solution to be measured, a potential is established through the glass membrane that covers the electrode. The colorimetric is simpler and uses substances called pH indicator strips that can be found in different presentations with properties to measure specific pH ranges. The most common indicator is litmus paper, which is a strip of paper with a special treatment that when submerged in a solution changes color and can measure with a high degree of sensitivity variations up to 0.5 pH Units according to the strip model used. The litmus papers are available to measure different ranges in the pH scale thanks to the chemical compound with which they are treated.

How do the pH strips work?

• The indicator paper strip is immersed in some chemical solution for examination.
• After 10 or 15 seconds you can compare the color obtained with the color scale that measures the pH, in this way you know the level of acidity or alkalinity of a solution.
• pH range: 0-14 and pH: 4.5-9
• Do not grab with wet fingers.
• Do not run, the dye stays on the strip, each pad of the strips retains the color and does not run or mix with each other.

The pH, is a very important biochemical parameter in all living organisms and in the environment; without pretending to be a society of compulsive gauges, if it is very important to measure everything we can change, and one of them is the pH, both ours and that of the elements that surround us, what we ingest, the water that we drink and with which we refresh in a pool, river or ocean. Measuring pH in industry, agriculture, aquaculture, among others, is important to obtain reproducible and stable results over time. A sophisticated method such as a low or high-end pH Metter, or a simple method such as pH strips BiochromCorp, are all valid methods to control this important parameter.