This paper describes the use of fullerene molecules, also known as buckyballs, as a stationary phase for liquid chromatography. The performance of the fullerene-modified stationary phase (FMS) is compared to that of a more common C18 stationary phase and to two other carbon-based stationary phases, PGC and COZ. A. 10A OM B. - Figure 1. Idealized drawing of the cross-section of a pore inside a silica particle, showing the relative densities of aminopropylsilyl (red/green) and fullerene (blue) groups: (A) full cross- section; (B) detailed view of covalent bonding of fullerene to the silica surface. Surface densities of silyl and fullerene groups were inferred from elemental composition results obtained at each stage of the synthesis (see Table 1). Absorbance (mAU, 220 nm) 700 600 500 400 300 200 100 a. Define selectivity, a, with words and an equation. b. Explain how the choice of stationary phase affects selectivity. c. Calculate the resolution of the nitrobenzene and toluene peaks in the top trace of Figure 2. (Estimate any values you need from the graph, and show your work.) Nitrobenzene FMS, 50 mm x 4.6 mm i.d., 5 μm Toluene C18, 100 mm x 4.6 mm i.d., 3 μm COZ, 100 mm x 4.6 mm i.d., 3 μm PGC, 50 mm x 4.6 mm i.d., 5 μm Figure 2. Normalized retention of toluene and nitrobenzene on a conventional C18 bonded phase compared to FMS, PGC, and COZ. Eluent compositions [acetonitrile/water (A/W) v/v] were adjusted to obtain a retention factor of about 6.0 for nitrobenzene in each case: FMS (23.5/76.5 A/W), C18 (35/65 A/W), COZ (43/57 A/W), and PGC (54/46 A/W). All other conditions were constant: flow rate 2 mL/min, column temperature 40 °C, and injection volume 1 μL 0 0 5 10 Normalized Time (t/tm) 15 20

Thin Layer Chromatography. All types of chromatography have mobile phaseand stationary phase. What is a stationary phase and a mobile phase? Elaborate your answer.

Is longitudinal diffusion of the solute a more serious problem in gas or in liquid chromatography? gas chromatography O liquid chromatography Why is longitudinal diffusion a more serious problem in this type of chromatography? Gas chromatography is carried out at higher temperatures than liquid chromatography. The solute must be volatile for application of gas chromatography. The linear velocity in gas chromatography is greater than the linaer velocity in liquid chromatography. Diffusion coefficients of gases are much greater than those of liquids.

The following statements are true for any chromatographic analysis except: The analyte component interacting most strongly with the stationary phase elute faster than those with weaker interactions. On the other hand, those with least interaction with the mobile phase elute the slowest. Interactions between mobile phase-analyte - stationary phase can be both chemical and physical in nature. Chromatography is a separation technique. Electromagnetic radiation source for XPS. Gamma ray X-ray UV-Visible Infra red Radiowave The part of SEM that is responsible for the production of electrons. * Electron guns Condenser lens Secondary detector Electron beam

1) Which of the following is a most appropriate reason to perform column chromatography over paperchromatography?a. The sample is a mixture of strictly polar particlesb. The sample is a mixture of strictly nonpolar particlesc. The goal is to separate and recover the parts of the mixtured. The densities of the component parts of the mixture differ

Two commonly used chromatography methods in labs are Nickel and streptavidin resin based colums. Explain which type of chromatography-ion exchange, size-exclusion, or affinity-these are, as well as their seperation mechanisms at a molecular level.

hree components in a mixture have varying distribution constants between the mobile phase and the stationary phass One of the components has a very low distribution constant, Would this component likely elute first or last and how would you design an experiment or modify the components of the separation to make it perform in the opposite manner?

2. A gas chromatogram of a four-(4)-component mixture had the following areas and retention times (RT). Component ABCD (RT) (min) 2.564 5.241 1.904 3.217 Area (mm²) 2341 1278 4302 1987 A. Which compound do you suspect is the most volatile? Why? B. Calculate the percent composition of component D.

Classify the stationary phases based on whether they are commonly used in reversed-phase liquid chromatography (RPLC) or normal-phase liquid chromatography (NPLC). RPLC pentafluorophenyl (-(CH₂)3 C6F3) octyl (-(CH₂), CH3) Answer Bank diol (-(CH₂), OCH₂CH(OH)CH₂OH) octadecyl (-(CH₂)17 CH3) phenyl (-(CH₂), C6H₂) NPLC amino (-(CH₂)2NH₂) cyano (-(CH₂)₂C=N)

Classify the stationary phases based on whether they are commonly used in reversed-phase liquid chromatography (RPLC) or normal-phase liquid chromatography (NPLC). RPLC NPLC Answer Bank octadecyl (–(CH,)17CH,) amino (-(CH,)3NH2) cyano (-(CH,),C=N) pentafluorophenyl (-(CH,);C,F;) diol (-(CH,),ОСH, СНIОH)СH,ОН) octyl (-(CH,),CH;) phenyl (-(CH, ),C,H;)