Atomic Spectroscopy in Food Analysis

Abstract

Since food is the primary source of essential elements for humans, the accurate and precise analysis of food materials is critical. The methods best suited to meet this task are atomic spectroscopic methods such as atomic absorption, atomic emission, and elemental mass spectrometry (MS). Methods commonly used in the generation of food composition data include flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma atomic emission spectrometry (ICP/AES), and more recently, inductively coupled plasma mass spectrometry (ICP/MS). FAAS and ICP/AES offer similar detection limits (DLs) (ng mL −1 levels), whereas, GFAAS and ICP/MS can provide sub‐ng mL −1 detection capability. The choice of a method often depends on detection capability, but ease of use, speed of analysis, and cost must be considered. ICP/AES and ICP/MS offer the advantage of providing simultaneous multielement measurements, making them well suited for the analysis of large numbers of elements in food samples. If one or a few elements are to be determined, less expensive atomic absorption spectrometry (AAS) methods might be more suitable. The most critical stage in the development of analytical methods is sample preparation. Samples can be prepared using numerous procedures, but the most useful for a wide range of analytes and sample matrices are based on dry ashing or wet ashing of the sample. In addition to total element determinations, speciation measurements are important to determine the exact form of the element that is present in the sample. Since the bioavailability of an element is dependent on its chemical form (speciation), the development of reliable methods for identification and quantification of trace element species is critical. The coupling of chromatographic separation and atomic spectroscopic detection has proven useful for elemental speciation measurements.

One Hundred Years of Progress in Food Analysis

“…Research on bioactive "functional" food compounds relies on the development of new assays with increased sensitivity and specificity to measure efficacious phytochemical components (anthocyanins, polyphenolic compounds), which are frequently colored. Atomic spectrometry methods including atomic absorption, atomic emission, and elemental mass spectrometry are routinely used to measure minerals (e.g., calcium, zinc) and heavy metals (e.g., lead, cadmium, mercury) in food products (67). Inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) offer the advantage of providing simultaneous multielement measurement in food samples.…”

“…The analyses of trace minerals (calcium, copper, iron, manganese, zinc) and toxic heavy metals (lead, cadmium, mercury) in foods were initially performed by wet chemical titration assays of precipitation complexes or reactions with chromogens to form colored products that can be quantified by light absorption . These techniques initially were replaced by the commercialization of atomic absorption spectrometry in 1963, followed later by inductively coupled plasma (ICP)−atomic emission spectrometry in the 1980s and ICP−mass spectrometry in the 1990s , . However, even at the present time, the analysis of table salt (sodium chloride) in foods is routinely determined as chloride by titration with silver ions.…”

Modern instrumentation and practical application of flame atomic emission spectrometry

“…water, beverages) direct determinations are possible with minimal sample processing such as dilution, degassing or evaporation of matrix components. Solid samples are decomposed by dry or wet ashing [65][66][67][68][69] as well as microwave decomposition [70].…”

Recent Techniques in Nutrient Analysis for Food Composition Database

“…AES has been widely used for the analysis of accurate and precise in food composition which enable consumers to make their food choices based on dietary reference intakes [ 72 ]. ICP-OES/AES was mostly used to determine the geographical origin of honey [ 48 ], wines [ 49 ], cumin [ 45 ], vinegar [ 50 ], coffee beans [ 46 ], baby foods, vegetables, milk powder [ 47 ] for minerals such as Mn, Zn, P, Fe, Cu, Rb, Mo, Ba, Sr and Ni.…”