8 Record(s)

De-ionized (or deionized) water

Ultrapure water from which dissolved solids and ionic content have been largely removed, often cations like sodium, calcium, iron, and copper, and anions such as chloride and sulfate. In a complete de-ionized water system, includes ultrafiltration and other methods to ensure the water conforms to specifications that include absence of microbial content and organic materials, as well as certain Conductivity requirements.

Dielectric constant

The ability of a non-conducting material to reduce the electrical interaction between two electrical charges. Water has a high dielectric constant.


The bending of waves, especially sound and light waves, around obstacles in their path. It is detectable in light waves by the presence of a pattern of closely spaced dark and light bands (diffraction pattern) at the edge of a shadow, and is a technique employed in elemental analysis.

Dietary Supplement

A product intended for oral consumption intended to provide nutrients in order to aid in supplementing the diet, as regulated by the Food & Drug Administration, under the Dietary Health And Education Action (DHSEA) of 1994.

Dose (Dosage)

A quantity of a medicine, drug, supplement or other substance recommended to take at a particular time.


A medicine or other substance that produces a physiological effect when ingested or is otherwise introduced into the body.

DSHEA (Dietary Supplement Health Education Act)

Groundbreaking legislation in 1994 resulting from consumers demanding their right to safe natural remedies and traditional medicines, which were allowed to remain on the market, but without making specific health claims. How Dietary Supplements Are Regulated in the USA, or visit the FDA web site.

Dynamic Light Scattering ( also Photon Correlation Spectroscopy)

This technique is one of the most popular methods used to determine the size of particles. Shining a monochromatic light beam, such as a laser, onto a solution with spherical particles in Brownian motion causes a Doppler Shift when the light hits the moving particle, changing the wavelength of the incoming light. This change is related to the size of the particle. It is possible to compute the sphere size distribution and give a description of the particle's motion in the medium, measuring the diffusion coefficient of the particle and using the autocorrelation function.