The HANNA dissolved oxygen portable test kit can determine the oxygen concentration in water quickly and easily. A modified Winkler method is used. Manganous ions react with oxygen in the presence of potassium hydroxide to form a manganese oxide precipitate. An azide is present to prevent any nitrite ions from interfering with the test. On addition of acid, manganese oxide hydroxide oxidizes the iodide to iodine. Since the amount of iodine generated is equivalent to the oxygen in the sample, the concentration of iodine is calculated by titration of thiosulfate ions that reduce the iodine back to iodide ions.

Boric acid/borate react with chemical compounds containing multiple hydroxyls groups (polyols) such as mannitol, generating anionic complexes at the neutral pH of water.

The borate esters are formed and dissociated spontaneously in a variety of pH dependent equilibria. During to the release of acidic protons during complexation there is a concomitant decrease of pH which tends to reverse the reaction and thus, in order to maintain stable complexes there is a need to avoid pH decrease. The amount of acidification produced upon the addition of mannitol is proportional to the extent of borate ester formation.

The HI 38074 test kit can determine boron concentration in irrigation waters by direct titration of boric acid.

Acidity, defined as percent oleic acid, is a parameter that indicates olive oil freshness. A high acidity value indicates the oil quality has diminished and is at risk of becoming rancid.

Acidity is used to discriminate an extra virgin olive oil from all other olive oils. According to the CEE 2568/91 regulation, olive oil is considered extra virgin when its acidity level is below 1%. A low acidity value also indicates a natural extraction process occurred soon after olive harvesting.

With the HI 3897 test kit, it is possible to easily and accurately test the quality of olive oil at various stages of processing and storage to monitor and maintain the highest quality. The HI 3897 kit utilizes a titration method where the endpoint is visually determined when the color changes from yellow-green to pink.

The chlorination of water supplies and polluted waters is used mainly to destroy or deactivate disease-producing micro-organisms. It also serves to improve the quality of drinking waters, as chlorine reacts with ammonia, iron, manganese, sulfide and some organic substances.

Nevertheless, high amounts of chlorine will produce adverse effects, like formation of compounds which are potentially carcinogenic (e.g. chloroform) or harmful to aquatic life (e.g. chloramines). Thus it is essential to control that the proper amount of chlorine has been added in order to fulfill the primary purpose of disinfecting and to minimize any adverse effects.