Determination of Pb in Geological Materials by Heat Extraction Slurry Sampling ET-AAS

Abstract

Lead (Pb) is a non-essential but extremely noxious metallic element, which is important for the assessment of environmental pollution. A simple and high throughput method involving fast heat extraction slurry sampling electrothermal atomic absorption spectrometry (HESS-GFAAS) was developed to detect trace Pb content in geological standard reference materials (SRMs). Compared with the traditional digestion method, the HESS-GFAAS method greatly reduces the time of sample pretreatment. The HESS-GFAAS technique improved Pb recovery and precision compared to conventional slurry sampling techniques. This optimized HESS-GFAAS procedure was performed as follows: first, the sample was added into 1 mL HNO3, 1 mL HCl and 1 mL HF, followed by heating for 30 min at 120 ℃ on a heating block; Next, dilute the solution with 50 mL water, and finally, the solution was introduced into a graphite tube with Pd(NO3)2-NH4H2PO4 as the mixed matrix modifier and analyzed by the GFAAS with a Pb electrodeless discharge lamp (EDL). To eliminate the interface of the geological sample matrix, the method of additions calibrate was used for Pb determination in geological samples. The results for 20 of these materials were in good agreement with the reference values. The characteristic mass and limit of detection for Pb based on the integrated absorbance for a 0.2% (m/v) sample were 14.8 ± 0.8 pg and 0.035 mg kg-1 , respectively. The accuracy (96.05-102.4% recovery) and precision (0.13-2.07%) of this procedure are illustrate by the results obtained for the 20 geological reference materials. The proposed method shows great potential for the determination of trace Pb in geological samples.

An environmentally friendly approach for the characterization of construction materials: determination of trace, minor, and major elements by slurry sampling high-resolution continuum source graphite furnace atomic absorption spectrometry

“…Dispersing media reported for metal determination by slurry sampling GFAAS usually consist of compounds with surfactant properties with the addition of an acid, mainly HNO 3 solutions due to its high purity and lack of interferences. 12,13,[16][17][18][19] This combination of reagents prevents the agglomeration and sedimentation of the solid particles by forming repulsive layers around them and/ or produces a partial dissolution of the solid sample and the extraction of metals. In general, the amount of metal extracted from the solid sample increases as the concentration of HNO 3 in the dispersing medium increases, but for too high acid concentrations, a faster deterioration of the graphite tube used for GFAAS measurement can also be observed.…”

“…[12][13][14][15][16] GFAAS methods for the direct analysis of solid samples have undergone signicant development since the arrival of highresolution continuum source AA spectrometers (HR-CS AAS) due to the higher background correction capability of these instruments. [17][18][19] Using these spectrometers, the main or secondary absorption lines and the wings of the absorption lines can be selected for the analytical measurements, and therefore the sensitivity for each element can be adjusted to the expected concentration level in the sample. [20][21][22] The main drawback of direct solid sampling GFAAS methods is the greater imprecision compared to GFAAS methods with liquid sample introduction due to the intrinsic inhomogeneity of solid samples and the small amount of sample introduced into the graphite tube for the analysis.…”

Novel Platinum–Nickel Composite Trap for Simultaneous and Direct Determination of Mercury and Cadmium in Soil and Its Mechanism Study

“…Electrothermal vaporization (ETV), as a versatile direct solid sampling approach, has been employed to combine with various atomic spectrometers or inorganic mass spectrometers for elemental analysis in soil, food, biological, and other samples. − The vaporizer’s features and elemental vaporization behaviors mainly depend on ETV materials, which are frequently fabricated into a strip, coil, rod, or furnace with high melting point metals (such as Ta, W, or Re), graphite, or metal ceramics. − Among them, graphite furnaces , are the most commonly used to directly introduce a solid or slurry sample and then couple with AAS and ICPOES/MS for elemental analysis including Hg and Cd; however, the high energy consumption, large water-cooling system, and <1 mg maximum sample size disable its field deployment. Thus, a high efficiency, small size, and low power consumption vaporizer should be designed for easy sample introduction and sensitive detection with the aim of miniature, field, and portable instrumentation fabrication.…”

Metal and Molecular Vapor Separation Analysis for Direct Determination of Mn and Cu by Atomic Absorption Detection, Free of Background Absorption

“…So far, a number of direct applications of solid samples into an electrothermal atomizer for atomic absorption spectrometry (AAS) have been investigated [1,2]. The direct analysis of solid materials has many advantages, such as no contamination from added chemicals, no separation/preconcentration steps, time-saving, a lower loss of volatile elements caused by digestion steps, and fewer chemical treatments.…”