Carbon peaks, identification

Figure 12.7 Cliromatograms of a polycarbonate sample (a) microcolumn SEC ti ace (b) capillary GC ti ace of inti oduced fractions. SEC conditions fused-silica (30 cm X 250 mm i.d.) packed with PL-GEL (50 A pore size, 5 mm particle diameter) eluent, THE at aElow rate of 2.0ml/min injection size, 200 NL UV detection at 254 nm x represents the polymer additive fraction ti ansfeired to EC system (ca. 6 p-L). GC conditions DB-1 column (15m X 0.25 mm i.d., 0.25 pm film thickness) deactivated fused-silica uncoated inlet (5 m X 0.32 mm i.d.) temperature program, 100 °C for 8 min, rising to 350 °C at a rate of 12°C/min flame ionization detection. Peak identification is as follows 1, 2,4-rert-butylphenol 2, nonylphenol isomers 3, di(4-tert-butylphenyl) carbonate 4, Tinuvin 329 5, solvent impurity 6, Ii gaphos 168 (oxidized). Reprinted with permission from Ref. (14).

Figure 14.7 Typical clnomatogram obtained by using the refinery analyser system shown in Figure 14.6. Peak identification is as follows 1, hydrogen 2, Cg+, 3, propane 4, acetylene 5, propene 6, hydrogen sulfide 6, iso-butane 8, propadiene 9, n-butane, 10. iso-butene 11, 1-butene 12, traw-2-butene 13, cw-2-butene 14, 1,3-butadiene 15, iso-pentane 16, w-pen-tane 17, 1-pentene 18, tro 5-2-pentene 19, cw-2-pentene 20, 2-inethyl-2-butene 21, carbon dioxide 22, ethene 23, ethane 24, oxygen + argon, 25, niti Ogen, 26, carbon monoxide.

The spray paint can was inverted and a small amount of product was dispensed into a 20 mL glass headspace vial. The vial was immediately sealed and was incubated at 80°C for approximately 30 min. After this isothermal hold, a 0.5-mL portion of the headspace was injected into the GC/MS system. The GC-MS total ion chromatogram of the paint solvent mixture headspace is shown in Figure 15. Numerous solvent peaks were detected and identified via mass spectral library searching. The retention times, approximate percentages, and tentative identifications are shown in Table 8 for the solvent peaks. These peak identifications are considered tentative, as they are based solely on the library search. The mass spectral library search is often unable to differentiate with a high degree of confidence between positional isomers of branched aliphatic hydrocarbons or cycloaliphatic hydrocarbons. Therefore, the peak identifications in Table 8 may not be correct in all cases as to the exact isomer present (e.g., 1,2,3-cyclohexane versus 1,2,4-cyclohexane). However, the class of compound (cyclic versus branched versus linear aliphatic) and the total number of carbon atoms in the molecule should be correct for the majority of peaks. 

Figure 13 Electropherogram of selected amino acids with end-column addition of 1 mM Ru (bpy)32+. Separation conditions 20 kV with injection of analytes for 8 s at 20 kV. Capillary, 75 im id, 62 cm long with a 4-cm detection capillary. Buffer 15 mM borate, pH 9.5. The electrode used for in situ generation of Ru(bpy)33+ was a 35-jlm-diameter carbon fiber, 3 mm long held at 1.15 V versus a saturated calomel electrode. The PMT was biased at 900 V. Peak identification (1) 100 fmol TEA, (2) 70 fmol proline (3) 1.6 pmol valine, (4) 50 pmol serine. Injection points. (From Ref. 97, with permission.)...

Fig. 42 Reversed-phase HPLC profiles of natural (top) and rearranged (bottom) butterfat triacylglycerols as obtained with the light-scattering detector. HPLC conditions Hewlett-Packard Model 1050 liquid chromatograph equipped with a Supelcosil LC-18 column (25 cm X 0.46-cm ID) coupled to a Varex ELSD II light-scattering detector. Solvent linear gradient of 10-90% propanol in acetonitrile at 25°C over a period of 90 min (1 ml/min) recording stopped at 70 min. Peak identification by carbon and double-bond numbers of triacylglycerols.

Figure 2. GC-FID chromatograms for the sulfide fractions from different Alberta petroleums. The peaks labeled B13 and B20 correspond to the bicyclic terpenoid sulfides with 13 and 20 carbons, respectively. The peak labeled T23 corresponds to the tetracyclic terpenoid sulfide with 23 carbons and peaks due to the hopane sulfides are indicated at the end of the chromatograms. The clusters of peaks spaced one carbon apart on the Bellshill Lake trace correspond mainly to complex mixtures of isomeric monocyclic sulfides possessing a linear carbon framework. These sulfides have been removed by biodegradation from the upper two samples. For more complete peak identification see References 9, 10 and 35. (Reproduced from Reference 34. Copyright 1989, American Chemical Society.)...

The results of an experiment at 308 K and 6.98 MPa are detailed here. The liquid phase contained 48 wt (74 mole %) carbon dioxide and the vapor phase contained 99.5 wt (99.8 mole %) carbon dioxide. A gas chromatogram for the lemon oil from the liquid phase sample is shown in Figure 3. Peak identification, retention, response value, and concentration are given in Table I. Composition of the lemon oil in the vapor phase is also listed. Average molecular weight of lemon oil is 137.9 in the liquid and 136.A in the vapor. 

Peak positions in an XPS spectrum are likely to be affected by spectrometer conditions and the sample surface. Before XPS peak identification, we often need to calibrate the binding energy. Calibration is particularly important for samples with poor electrical conductivity. Calibration can be done with an internal standard that has a peak that shows little or no chemical shift, for example, elemental Si. The most common method is use of the C Is peak at 285 eV from carbon adsorbed on the sample surface. The carbon from organic debris (as C—H or C-C) in air is found on all samples exposed to the environment. The peaks of core level binding energies as listed in Table 7.1 are sufficiently unique for element identification. 

A Varian XLFT-100 Fourier Transform nmr Spectrometer interfaced with a Varian 620-L minicomputer with magnetic tape storage provided high-resolution, proton-decoupled spectra of natural abundance carbon-13 at 25.2 MHz. For identification of carbon peaks, chloroform-d solutions of surfactant (solubility about 20 wt%) were prepared. Chloroform-d also served for a deuterium field lock. Samples of surfactant in water or decane were placed... 

Figure 4.17. Separation of a mixture of inorganic and organic anions by gradient elution ion chromatography with conductivity detection using a micromembrane suppressor. A variable rate gradient from 0.5 mM to about 40 mM sodium hydroxide on an lonPac ASH column was used for the separation. Peak identification 1 = isopropylmethylphosphonate 2 = quinate 3 = fluoride 4 = acetate 5 = propionate 6 = formate 7 = methylsulfonate 8 = pyruvate 9 = chlorite 10 = valerate 11 - monochloroacetate 12 - bromate 13 = chloride 14 = nitrite 15 = trifluoroacetate 16 = bromide 17 = nitrate 18 = chlorate 19 = selenite 20 = carbonate 21 = malonate 22 = maleate 23 = sulfate 24 = oxalate 25 = ketomalonate 26 = tungstate 27 = phthalate 28 = phosphate 29 = chromate 30 = citrate 31 = tricarballylate 32 = isocitrate 33 = cis-aconitate and 34 = trans-aconitate. Each ion is at a concentration between 1 to 10 mg/1. (From ref. [417]. Marcel Dekker).

Figure 7.3. Separation of organotin compounds on a 10 cm x 1 mm I.D. column packed with Deltabond Methyl with supercritical fluid carbon dioxide saturated with formic acid as mobile phase. The separation was obtained at 60°C using pressure programming 0.5 min hold at 90 atm. Then programmed at 4 atm / min to 150 atm where the program rate was increased to 10 atm / min to 300 atm. Peak identification 1 = dibutyltin dichloride 2 = tributyltin chloride 3 = tetrabutyltin 4 = diphenyltin dichloride 5 = dicyclohexyltin dichloride 6 = bis(tributyltin) oxide 7 = triphenyltin chloride 8 = tricyclohexyltin chloride 9 = tetraphenyltin 10 = tetracyclohexyltin 11 = bis(triphenyltin) oxide and 12 = hexakis(2-methyl-2-phenylpropyl) distannoxane. (From ref. [42] Springer-Verlag)...

Figure 4 Separation of a standard sample containing 13 food additives. Peak identification , caffeine 2, aspartame 3, sorbic acid 4, benzoic acid 5, saccharin 6, green S 7, acesulfame K 8, sunset yellow FCF 9, quinoline yellow 10, brilliant blue FCF 11, carmoisine 12, ponceau 4R 13, black PN. Conditions fused-silica capillary 50 m i.d. x 48.5cm with x3 extended path length detection cell separation buffer, 20mmoll carbonate, pFI 9.5, containing 65mmoll SDS applied voltage, 20kV temperature, 25°C.

Figure 3 Ion chromatogram of a condensate discharge water sample. Peak identification 1 =fluoride, 2 = acetate, 3=formate, 4 = chloride, 5 = nitrite, 6 = carbonate, 7 = sulfate, 8 = unknown, 9 = nitrate, 10 = unknown, 11 = phosphate. (Reprinted with permission from Lu Z, Liu Y, Barreto V, etal. (2002) Determination of anions at trace levels in power plant water samples by ion chromatography with electrolytic eluent generation and suppression. Journal of Chromatography A 956. 129-138 Elsevier.)...

Survey and detailed high-resolution spectra were measured on both the disc and on the ball. Survey spectra were used for peak identification and to check the presence of contaminants. Detailed spectra of phosphorus 2p, together with zinc 3s, sulphur 2p, carbon Is, oxygen Is, iron 2p, zinc 2p3/2 and zinc LMM were recorded to identify the different chemical states of the species and to perform the quantitative analysis. 

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