Comparison of Three Aqua Regia Digestion Methods for Twenty Florida Soils

Abstract

soil and sludge samples based on it, in addition to the total elemental concentrations (Vercoutere et al., 1995; It is important to evaluate different digestion methods to accurately Quevauviller et al., 1993). In many countries (excluding determine elemental concentrations in soils. Three commonly used digestion procedures, hotplate aqua regia, microwave aqua regia, and the USA), this procedure is required by regulations to microwave aqua regia ϩ HF, were compared for digestion of three estimate the impact of soil amendments such as sewage standard reference materials (SRMs 2704, 2709, and 2711) and 20 sludge on the environment (Krause et al., 1995; Marr Florida soils (three groups of Quartzipsammemts, one group of Alaet al., 1995; Vercoutere et al., 1995). However, this proquods, and one group of Paleudults). Sixteen elements (Al, Ba, Ca, cedure is very tedious and time-consuming (Siaka et Fe, K, Mg, Mn, P, Zn, As, Cd, Cr, Cu, Ni, Pb, and Se) were analyzed al., 1998). In addition, if open systems are used during using either an inductively coupled plasma optical emission spectromdigestion, there are risks of atmospheric contamination eter (ICP-OES) or a graphite furnace atomic absorption spectrophoand volatilization losses of volatile compounds during tometer (GFAAS). Precise analysis was achieved for all elements the oxidation of organic substances of the soils (Kubraexcept As (1.0-25%), Cd (1.8-22%), and Se (4.1-22%) in the SRMs kova, 1997; Nieuwenhuize et al., 1991; Quevauviller et using all three procedures, with the microwave aqua regia ϩ HF procedure having slightly better precision (3.7%) averaged across all al., 1993). elements. Compared with the elemental recoveries in SRMs by the Since the 1980s, microwave-assisted sample digestion microwave aqua regia digestion (80%), microwave aqua regia ϩ HF techniques have become popular and are widely used digestion achieved greater accuracy (94%), whereas the hotplate aqua (Chen and Ma, 1998; Quevauviller et al., 1993; Smith regia digestion achieved less accuracy (74%). In general, the microand Arsenault, 1996). Microwave-assisted aqua regia wave aqua regia ϩ HF digestion was overall the best procedure for digestion using a Teflon bomb is considered a rapid determining concentrations of most metals in SRMs and Florida soils, sample digestion method (Marr et al., 1995; Nieuwenhufollowed by the microwave aqua regia and the hotplate aqua regia ize et al., 1991; Paudyn and Smith, 1992; Rantala and digestion. However, this so-called total-total digestion procedure (mi-Loring, 1989). This technique provides a rapid, safe, and crowave aqua regia ϩ HF) may underestimate total Pb concentration efficient digestion and is not susceptible to losses of in Florida soils and total Al, Ca, Fe, Mg, and Ba concentrations in the Florida Paleudults. * Significant at the 0.05 probability level. ** Significant at the 0.01 probability level. *** Significant at the 0.001 probability level. † Arithmetic mean Ϯ standard deviation. ‡ Paired t-test (least significant difference) at ␣ ϭ 0.0...

Chromium in Soil Organic Matter and Cowpea After Four Consecutive Annual Applications of Composted Tannery Sludge

“…The selection of this method was based on the objective of estimating the environmental availability of trace elements. Thus, recovery of the Cr in the reference samples may be considered satisfactory when compared to the methods using HNO 3 , HCl, H 2 O 2 , and HF (Chen and Ma, 2001;Vieira et al, 2005).…”

Enriched cocoa pod composts and their fertilizing effects on hybrid cocoa seedlings

“…Total organic C and total N were analyzed by the dry combustion and micro-Kjeldahl method, respectively. Total elemental composition (P, K, Ca, Mg and S) was estimated in Aqua Regia (concentrated HCl-HNO 3 at 3:1 v/ v ratio) digested samples in an Inductively Coupled Plasma-Optical Emission Spectrophotometer (Varian 725ES model) (Chen and Ma 2001). The pH was recorded after suspending the feed-stocks and compost sample powders in deionized water (1:10 w/v) for 1 h using a pH meter.…”

Assessment of the distribution of potentially harmful trace elements in bedrocks and stream sediments of Okemesi-Ijero area, Southwestern, Nigeria

“…The Campbell et al (2008), to evaluate the quality of analytical method. The detection limits of ICP-MS were evaluated with respect to the protocols of Chen and Ma (2001) and were found to range between (0.0001 -0.1) mg/kg for the thirteen elements considered in this study. Two distinct indices were used in the assessment of the level of enrichment and ecological risk by PTEs contamination in the stream sediments of Okemesi-Ijero, southwestern, Nigeria.…”