Composed of a single proton and a single electron, hydrogen is the simplest and most abundant element in the universe. It is estimated that 90% of the visible universe is composed of hydrogen. Hydrogen is the raw fuel that most stars 'burn' to produce energy. The same process, known as fusion, is being studied as a possible power source for use on earth. The sun's supply of hydrogen is expected to last another 5 billion years. Hydrogen is a commercially important element.
Eau de toilette is a lightly scented cologne used as a skin freshener. The term toilette/toilet used in this context describes the process of washing and personal grooming. Eau de toilette is also referred to as aromatic waters and has a high alcohol content.
But still the most straightforward difference between a Perfume, Eau de Parfum, Eau de Toilette and a Cologne is the concentration of oils used in the fragrance. 1  A Cologne or sometimes called an Eau de Cologne or an Eau Fraiche is between 2-5% Perfume oil. 2  An Eau de Toilette is between 4-10% Perfume oil.