Rapid determination of inorganic elements in airborne particulate matter by using acidified subcritical-water extraction and inductively-coupled plasma?optical-emission spectrometry

Abstract

A rapid and simple method has been developed for determination of inorganic elements in airborne particulate matter (PM10) by using acidified subcritical water and ICP-OES. Elements such as Al, As, B, Ba, Cd, Cu, Fe, Mn, Pb, Se, and Zn were rapidly and efficiently extracted from PM10 samples with a solution of 0.1 mol L(-1) HNO(3) under subcritical conditions. The method requires approximately 5% of the amount of acid used in the standard microwave extraction procedure. The material selected for the subcritical extraction manifold was poly ether ether ketone (PEEK), to avoid sample contamination with elements present in previously reported stainless-steel manifolds. The extraction temperature, time of static and dynamic extraction, and flow rate of acidified water were studied keeping the pressure controlled at about 1,500 psig. The efficiency of extraction of most of the analytes increased with temperature, tending to quantitative extraction at temperatures near 150 degrees C. After the extraction process the analytes were determined directly in the extract by ICP-OES. When the method was compared with the USEPA counterpart, the results indicate that under optimized conditions (static extraction time: 15 min, dynamic extraction time: 30 min, flow rate: 2 mL min(-1)) the analytes were extracted with recoveries between 73 and 158%. Alternatively, by using an extraction time of 15 min, the method could be used to screen for all the elements, with recoveries over 50%. The developed method was applied to the determination of inorganic elements in airborne particulate matter in the atmosphere of Santiago, Chile.

Abnormal absorption of subcritical water posts in microwave heating

“…Subcritical water extractions are based on the pressurized microwave‐assisted extraction, due to the volumetric heating and fast heating . In this case, water is heated by microwave energies with maintaining the liquid state . The pressurized microwave‐assisted subcritical water extraction has been applied in chemical engineering, medicine industries and environmental engineering, but it still bears the shortcomings of the heating nonuniformity, the low heating efficiency and safety issues.…”

“…[11][12][13][14][15] In this case, water is heated by microwave energies with maintaining the liquid state. [14][15][16][17][18][19][20][21] The pressurized microwave-assisted subcritical water extraction has been applied in chemical engineering, medicine industries and environmental engineering, but it still bears the shortcomings of the heating nonuniformity, the low heating efficiency and safety issues. In order to overcome these difficulties, the physical mechanism between microwaves and subcritical water should be well understood, but it has been not yet reported.…”

Characterization of Urban Particulate Matter by Diffusive Gradients in Thin Film Technique

“…Application of these procedures to fractionation studies (e.g., [ 15 ]) is limited because airborne particulate matter, unlike soil, sediments, and fly ash, is only available with very limited sample amounts collected on filters, typically at submilligram to milligram level [ 11 ]. To overcome problems associated with this special kind of sample, various approaches were introduced [ 16 – 18 ]. Instead of whole sample only aliquots of the sample in the form of either circular parts or punches of the sampling filter substrate with homogeneously distributed particulate matter were used, which enables loading of sample into the extraction unit.…”

Use of chelating solvent-based pressurized liquid extraction combined with inductively coupled plasma-optical emission spectrometry for trace element determination in atmospheric particulate matter

“…Atmospheric particulate matter is usually collected on quartz fiber filters prior to analysis. Since most of the analytical techniques for metals are based on spectrometric determinations, such as flame atomic absorption spectrometry (FAAS), [6][7][8] electrothermal atomic absorption spectrometry (ETAAS) [9][10][11] and multi-elemental ICP-MS 6,[12][13][14] and ICP-OES, [15][16][17][18][19] high efficiency digestion procedures involving the use of hydrofluoric acid are needed to destroy the quartz fiber filter. 12,14,[20][21][22] The selection of a suitable combination of mineral acid mixtures has been reported as quite important.…”