Development of a Manganese Speciation Method for Atmospheric Aerosols in Biologically and Environmentally Relevant Fluids

Figures & data

FIG. 1 Example spectra of the formaldoxime (FAD) method. Almost identical spectra are obtained for two solutions of equal manganese concentration, but varying iron concentration, showing that the iron interference can be eliminated at ppb levels by complexation with EDTA at slightly basic conditions (pH = 7.5). Baseline (BL) subtracted Absorbance values are shown at 450 nm.

TABLE 1 Comparison of leachable manganese with total manganese values

(Sample)	(Extractant)	(Leachable ng Mn m^− 3)	(Total ng Mn m^− 3)	(% Leachable (from ICP-MS values))
(St. Louis, March 17, 2005)	(NaCl)	(2.0 ± 0.2)	(18.3 ± 1.0)	(11.3)
(St. Louis, March 17, 2005)	(Acetate Buffer)	(3.6 ± 0.3)	(18.3 ± 1.0)	(20.2)
(St. Louis, March 17, 2005)	(Bicarbonate)	(1.16 ± 0.11)	(18.3 ± 1.0)	(6.3)
(St. Louis, March 17, 2005)	(Milli Q Water)	(2.1 ± 0.2)	(18.3 ± 1.0)	(11.8)
(St. Louis, March 21, 2005)	(NaCl)	(0.41 ± 0.04)	(8.3 ± 0.7)	(6.9)
(St. Louis, March 21, 2005)	(Acetate Buffer)	(1.1 ± 0.1)	(8.3 ± 0.7)	(12.8)
(St. Louis, March 21, 2005)	(Bicarbonate)	(0.55 ± 0.05)	(8.3 ± 0.7)	(5.0)
(St. Louis, March 21, 2005)	(Milli Q Water)	(0.33 ± 0.03)	(8.3 ± 0.7)	(4.1)

FIG. 2 Plots of how the extract solution affects the soluble manganese present in PM10 samples collected in East St. Louis, IL. Each date consists of four co-located samples submitted to a different extract solution. In acetate solution, the fraction of the total manganese extracted is 20% and 13% for March 17 and 21, respectively.

TABLE 2 Comparison of soluble (pH = 4.3 acetate buffer) manganese air and particle concentrations for PM10 samples collected in East St. Louis and Toronto. PM10 mass values for Toronto are summed for each stage of the PCIS

(Sample)	(PM10 Mass (μg m^−3))	(ng Mnsol/μg PM)	(ng Mnsol m^− 3)
(St. Louis, March 17, 2005)	(41.0)	(0.09)	(3.57)
(St. Louis, March 19, 2005)	(32.8)	(0.03)	(0.83)
(St. Louis, March 21, 2005)	(33.3)	(0.03)	(1.06)
(Toronto, Dec 30, 2005)	(23.6)	(0.03)	(0.64)
(Toronto, Jan 2, 2006)	(36.3)	(0.02)	(0.75)

TABLE 3 Comparison of soluble manganese versus soluble oxidized manganese concentrations for PM10 and PM2.5 samples collected in Toronto. PM10 and PM2.5 mass values are summed for each stage of the PCIS

(Sample)	(Total Mn by ICPMS (ng m^− 3))	(Soluble Mn (ng m^− 3))	(Soluble oxidized Mn (ng m^− 3))	(% Oxidized Mn of soluble [as Mn(III)])	(% Oxidized Mn of total [Mn(III)])
(Toronto, December 30, 2005, PM2.5)	(N/A)	(0.15)	(0.06)	(40)	(N/A)
(Toronto, December 30, 2005, PM10)	(N/A)	(0.65)	(0.06)	(9.7)	(N/A)
(Toronto, January 2, 2006, PM2.5)	(N/A)	(0.23)	(0.05)	(21)	(N/A)
(Toronto, January 2, 2006, PM10)	(N/A)	(0.75)	(0.05)	(6.4)	(N/A)
(Toronto, January 13 and 19, 2006)	(4.2)	(1.6)	(0.28)	(18)	(6.6)
(Composite PM2.5)
(Toronto, January 13 and 19, 2006)	(6.9)	(2.6)	(0.31)	(12)	(4.5)
(Composite PM10)

FIG. 3 Size-fractionated soluble manganese (Figure 3a) and soluble oxidized manganese (Figure 3b) air concentrations measured in Toronto by the formaldoxime method and the o-tolidine method, respectively. Note that soluble manganese was detected in particles < 0.5 μ m. Also, note that no oxidized manganese was detected in the coarse fraction, which was the most dominant overall soluble manganese fraction.