Table 1. Physical and Morphological Characteristics of Graphite Standard (GST), and of -400 Mesh Spherical Fe Powder (-400MSIP)a a Also shown are the physical and morphological characteristics of ICM and GCI by our previous method7 and of GCIP by our optimized method.13 The SEM pictures (2nd, -400MSIP; 4th, GCI; 5th, GCIP from top) were from ref 13. crystal, the carbon classiﬁcation in Figure 1, enabled the degree of crystal to be ranked (high to low) as graphite crystal > t-C > g-C > i-C. The i-C is highly disordered and approximates a-C. Finally, the GCIP was the most facile to tamp into the AMS target holder. Figure 3 showed FT-IR transmission spectra of GST and of the AMS targets ICM, GCI, and GCIP, all showed a water band at ∼1630 cm-1, and except for ICM, and all showed a band at ∼1580 cm-1 that corresponded to the sp2 bond (CdC bond stretching) in graphite. The band at ∼1580 cm-1 indicated that GCI and GCIP each had a carbon hexagonal structure. Figure 4 summarized the Raman spectra of GST, ICM, GCI, and GCIP (left panel) in relation to Raman spectra from the scientiﬁc literature (right panel) with permission. The D, G, and G′ (G′ ) 2D ) D*) bands correspond to the sp3 bond (diamond- like carbon), sp2 bond (graphite and graphite-like carbon), and stacking arrangement without disorder (graphite crystal), respec- tively. The GST showed intense G and G′ bands at 1566.3 and 2705.4 cm-1 and weak D and D′′ bands at 1339.0 and 3228.5 cm-1, respectively. The ICM appeared to have only weak D and G bands 7664 Analytical Chemistry, Vol. 80, No. 20, October 15, 2008 at 1329.4 and 1584.7 cm-1 and no evidence of G′ or a G + D combination band that would indicate second-order Raman scat- tering. The GCI showed intense D and G bands at 1321.5 and 1585.7 cm-1, respectively. In addition, GCI showed G′, G + D combination, and D′′ bands at 2655.7, 2917.2, and 3203.6 cm-1 respectively. The Raman spectrum of GCIP was similar to that of GCI, and it also showed the ﬁrst-order (D and G bands) and second-order Raman scattering (G′, G + D, and D′′ bands). The full width at half-maximum height (fwhm, ∆ ) of D, G, and G′ bands in GST was narrow, while the fwhm of those same bands in ICM, GCI, and GCIP were two to three times broader than those same corresponding bands in GST. The in-plane crystallite size (La) was inversely proportional to the ID/IG, and GST > GCI > ICM ) GCIP were ranked large to small based on their La. Figure 5, panel A showed the XRD spectra of GST and -400MSIP. The GST had an intense diagnostic graphite-002 reﬂection peak (G-002) at ∼26.5°; its intensity was 5-33 times greater than that of G-004, G-100, or G-101 peaks. Thirty mil- ligrams of GST had a stacking height of crystal (often called Lc) of 15.42 nm and an interlayer distance (d) of 0.334 nm. The