Abstract
Ashing is an important first step in proximate or specific mineral analysis. Ash refers to the inorganic (mineral) residue remaining after the combustion or complete acid-facilitated oxidation of organic matter in food. This chapter covers the instrumentation, principles, procedures, advantages, and disadvantages various ashing procedures. The two major types of ashing analysis, dry ashing and wet ashing, can be accomplished by conventional means or by the use of microwave systems. The procedure of choice depends upon the use of the ash following its determination, and limitations based on cost, time, and sample numbers. Conventional dry ashing is based upon sample incineration at high temperatures (500-600°C) in a muffle furnace. Wet ashing (acid-facilitated oxidation) is often used as a preparation for specific elemental analysis by atomic absorption, inductively coupled plasma, and/or mass spectrometry. Microwave ashing (dry or wet) is faster than conventional methods and requires little additional equipment or space, but sample throughput may be a limiting factor.
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References
Analytical Methods Committee (1960) Methods for the destruction of organic matter. Analyst 85: 643–656. This report gives a number of methods for wet and dry combustion and their applications, advantages, disadvantages, and hazards.
Akinyele, IO, Shokunbi, OS (2015) Comparative analysis of dry and wet digestion methods for the determination of trace and heavy metals in food. Food Chem 173: 682–684.
AOAC International (2016) Official methods of analysis, 20th edn. (On-line). AOAC International, Rockville, MD. This reference contains the official methods for many specific food ingredients. It may be difficult for the beginning student to follow.
Aurand LW, Woods AE, Wells MR (1987) Food composition and analysis. Van Nostrand Reinhold, New York. The chapters that deal with ash are divided by foodstuffs. General dry ashing procedures are discussed under each major heading.
Bakkali K, Martos NR, Souhail B, Ballesteros E (2009) Characterization of trace metals in vegetables by graphite furnace atomic absorption spectrometry after closed vessel microwave digestion. Food Chem 116(2): 590–594.
Kuboyama, K, Sasaki, N, Nakagome, Y, Kataoka, M (2005) Wet Digestion. Anal Chem 360: 184–191.
Mesko MF, De Moraes DP, Barin JS, Dressler VL, Knappet G (2006) Digestion of biological materials using the microwave-assisted sample combustion technique, Microchem J 82: 183–188.
Neggers YH, Lane RH (1995) Minerals, ch. 8. In: Jeon IJ, Ikins WG (eds) Analyzing food for nutrition labeling and hazardous contaminants. Marcel Dekker, New York. This chapter compares wet and dry ashing, and summarizes the following in tables: losses of specific elements during dry ashing; acids used in wet oxidation related to applications; AOAC methods for specific elements related to food applications.
Palma M N N, Rocha G C, Valaderes Filho SC, Detman E (2015) Evaluation of Acid Digestion Procedures to Estimate Mineral Contents in Materials from Animal Trials. Asian-Australas J Anim Sci 11: 1624–1628.
Pomeranz Y, Meloan C (1994) Food analysis: theory and practice, 3rd edn. Chapman & Hall, New York. Chapter 35 on ash and minerals gives an excellent narrative on ashing methods and is easy reading for a student in food chemistry. A good reference list of specific mineral losses is given at the end of the chapter. No stepwise procedures are given, however.
Smith GF (1953) The wet ashing of organic matter employing hot concentrated perchloric acid. The liquid fire reaction. Anal Chim Acta 8: 397–421. This reference gives an in-depth review of wet ashing with perchloric acid. Tables on reaction times with foodstuffs and color reactions are informative and easy for the food scientist to understand.
Wehr HM, Frank JF (eds) (2004) Standard methods for the examination of dairy products, 17th edn. American Public Health Association, Washington, DC. This text gives detailed analytical procedures for ashing dairy products
Wooster HA (1956) Nutritional data, 3rd edn. H.J. Heinz, Pittsburgh, PA.
Zhang H, Dotson P (1994) Use of microwave muffle furnace for dry ashing plant tissue samples. Commun Soil Sci Plant Anal 25 (9/10): 1321–1327.
Acknowledgment
The author of this chapter wishes to acknowledge the contributions of Dr. Leniel H. Harbers (Emeritus Professor, Kansas State University) for previous editions of this chapter. Also acknowledged in the preparation of this chapter is the assistance of Dr. John Budin (Silliker Laboratories, Chicago Heights, IL) as well as Michelle Horn, Ruth Watkins, and Anthony Danisi (CEM Corporation, Matthews, NC).
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Harris, G.K., Marshall, M.R. (2017). Ash Analysis. In: Nielsen, S.S. (eds) Food Analysis. Food Science Text Series. Springer, Cham. https://doi.org/10.1007/978-3-319-45776-5_16
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DOI: https://doi.org/10.1007/978-3-319-45776-5_16
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