English photomicrographer Spike (M.I.) Walker has been a consistent winner of the Nikon Small World competition for many years and has published many articles and a book about microscopy. Featured below is a photomicrograph of recrystallized Vitamin C (pale blues and greens).

Beautiful cyan spherulites of recrystallized vitamin C are revealed with striking red concentric ribbons spaced in almost equal intervals. The crystal growth front was selectively altered by Spike Walker during preparation of the specimen. Polarized light and a "Spikeberg" disc were used to illuminate the specimen along with a 12-volt, 100-watt tungsten-halide lamp. The objective was a planapochromat 4x/0.16 NA coupled to a low-power achromatic condenser. The microscope used in the study was a Zeiss Ultraphot III with an automatic 35-millimeter photohead. The film was Fujichrome Velvia. (10x)

Ascorbic acid, also known by the chemical name L-ascorbic acid, is a water-soluble vitamin that functions as a powerful antioxidant. Although most animals can synthesize vitamin C, others -- such as humans, other primates, and guinea pigs -- obtain it only through their diets. Vitamin C is commonly found naturally in peppers, citrus fruits, tomatoes, melons, broccoli, and green leafy vegetables such as spinach, turnip, and mustard greens.

Vitamin C is known to be essential in a variety of metabolic functions, but the details of its mechanism aren't yet understood. It is necessary for synthesis of collagen (a protein important in the formation of healthy skin, tendons, bones, and supportive tissues and in wound healing); maintenance of the structural strength of the blood vessels; metabolism of certain amino acids; and the synthesis or release of hormones in the adrenal glands. Although some anecdotal evidence suggests that vitamin C plays a part in protecting the body against infection, that claim has not been scientifically proven yet.

Chemically, L-ascorbic acid occurs as a white or slightly yellow crystal or powder with a slight acidic taste and darkens on exposure to air and light. As a dry state, it is reasonably stable in air, but it rapidly oxidizes in solution. Ascorbic acid is freely soluble in water; sparingly soluble in alcohol; insoluble in chloroform, ether, and benzene.

BACK TO SPIKE WALKER GALLERY

Questions or comments? Send us an email.

Text and graphics for this article are
© 2000-2022 by Spike (M. I.) Walker.
All Rights Reserved under copyright law.

© 1995-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.

This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.

Last modification: Friday, Nov 13, 2015 at 01:18 PM

Access Count Since November 18, 2000: 13101

Microscopes provided by: