UV chromatogram

Similarly, estimation of chemical composition of soluble polymer was also dependent on selectivity of the UV detector. Polymerized acrylonitrile has no significant UV absorbance at 230 and 254 nm. Thus, UV chromatograms were used to estimate amounts of polymerized methylacrylate and styrene In each resin system. The refractometer detector was sensitive to polymerized methylacrylate and styrene, as well as to polymerized acrylonitrile. It was therefore necessary to calculate comonomer contribution to refractometer peak areas In order to estimate concentration of polymerized acrylonitrile. This was done by obtaining a refractometer calibration for all three homopolymers. Quantity of polymerized comonomers measured by UV were then converted to equivalent refractometer peak areas. Peak areas due to polymerized acrylonitrile were then calculated by difference, and used to calculate amount of polymerized acrylonitrile. 

Figure 7.4 SFE-SFC-UV chromatogram of an HDPE/(Irgafos 168, Irganox 1010) extract. After Tikuisis and Dang [112]. Reprinted with permission from T. Tikuisis and V. Dang, in Plastics Additives, An A-Z Reference (G. Pritchard, ed.), Chapman Hall, London, pp. 80-94 (1998) Copyright CRC Press, Boca Raton, Florida...

Figure 7.23 (a) LC-UV chromatogram (275 nm) of a PVC sample extract (b) FTIR spectra of peaks. Legend (1) monoesterified... 

Figure 7.44 shows the 2D UV chromatogram (RPLC-UV/VIS (DAD)) for a five-compound test mixture of polymer additives [662]. Any spectral data collected during hyphenated chromatography-spectroscopy measurements can be readily transformed into 2D correlation spectra. 

Figure 7.44 2D UV chromatogram (254 nm) for a five-compound test mixture. After Louden et al. [662]. Reproduced from D. Louden et al., Anal. Bioanal. Chem., 373, 508-515 (2002), by permission of Springer-Verlag, Copyright (2002)...

Figure 9.10 HPLC-UV chromatogram of the 26 h microbial incubation of 5-ketoprofen with Streptomyces sp. ATCC 55043...

Fig. 3.43. UV chromatogram as obtained in the LC/NMR ran of fraction A. For chromatographic conditions see text. Reprinted with permission from A. Preiss el al. [117].

Fig. 3.59. HPLC-UV chromatogram at 230 nm for the analysis of azo dyes, (a) Disperse red 1 (b) Solvent yellow 14 (c) Solvent red 24. Reprinted with permission from M. C. Garrigos el al. [129].

Fig. 3.61. HPLC-UV chromatogram at 230 nm for the analysis of the aromatic amines listed. (1) 1,4-Diaminobenzene (2) 2-chloro-l,4-diaminobenzene (3) 2,4-diaminotoluene (4) benzidine (5) 4,4 -oxidianiline (6) aniline and 4-nitroaniline (7) o-toluidine (8) 4,4 -methylenedianiline (9) 3,3 -dimethoxibenzidine (10) 3,3 -dimethylbenzidine (11) 4-chloroaniline and 2-amino-4-nitrotoluene (12) 4,4 -thiodianiline (13) p-cresidine (14) 2,4-dimethylaniline (15) 2-naphty-lamine (16) 4-chloro-o-toluidine (17) 4,4 -methylene-di-o-toluidine (18) 2,4,5-trimethylaniline (19) 4-aminobiphenyl (20) 3,3 -dichlorobenzidine (21) 4,4 -methylenbis (2-chloroaniline) and (22) o-aminoazotoluene. Reprinted with permission from M. C. Garrigos et al. [130].

FIGURE 22 (a) HPLC/UV chromatogram, (b) ESI LC/MS total ion chromatogram, (c) extracted mass spectrum for RT = 25.35 min peak without background subtraction, (d) Extracted mass spectrum for the same peak with background subtraction. 

FIGURE 27 LC/UV chromatogram shows two late eluting peaks for the discolored tablets at retention time of 24.2 and 30.4 min. 

Fig. 12.18 Single bead FTIR spectra (A) and HPLC/UV chromatograms (B) of resin (40) at various times during the n-butylamine cleavage reaction.

An example where this was utilised effectively is seen where compound X showed an intense fragment ion at miz 112. Figure 6.19 shows the TIC produced from precursor ion scanning for mIz 112. When compared with the UV chromatogram it can clearly show which peaks contained the partial structure for fragment ion miz 112 and in some cases show components not seen by UV detection. 

Figure 6.30 UV chromatogram of a drug substance. Expanded section from 13 to 17 min along with two mass traces for the peak at RT 14.9 min and the corresponding product ion spectrum of mJz 780. Reproduced from [22] with permission of John Wiley and Sons Ltd.

While identification of the peaks in a LC-UV chromatogram is possible by comparing retention times and UV spectra with authentic samples or a databank, this might not be possible for compounds with closely related structures, and wrong conclusions might be drawn. It has been established that in order to complete the characterization of phenolic compounds, reagents inducing a shift of the UV absorption maxima can be used. ... 

Figure 10 UV chromatogram (top trace) and CD chromatogram (bottom trace) of the trfoil AMIDE KNOT. SINCE THE KNOT IS THE ONLY CHIRAL PRODUCT, THE CD TRACE, WHICH SHOWS TWO BANDS OF EQUAL INTEGRATIONS WITH OPPOSITE SIGNS OF THE CD SIGNAL, PROVIDES EVIDENCE FOR THE FORMATION AND SUCCESSFUL SEPARATION OF BOTH ENANTIOMERS BY CHIRAL HPLC.

Without backpressure regulation for each channel, it is necessary to minimize the flow rate fluctuation over time. The relative standard deviation (RSD%) in retention time variation among the eight channels over 1 month for compounds A and B was less than 2% and for C and D it was less than 1%. The RSD% for all channels over a 1-month period for compounds A to D was 3.2, 2.4,1.6, and 1.5%, respectively. Therefore, this system is well suited for combinatorial library analysis. The UV chromatograms from channel 5 from different days are shown as an example in Fig. 2A. The retention times of the four compounds (compounds A to D) from all eight channels during a 1-month period are shown in Fig. 2B. 

Fig. 5. UV chromatograms of the standard mixture separated using 2.1-mm-i.d. columns at 12 ml/min Polaris (A), Zorbax (B), Omnisphere (C), Luna (D), and Aqua (E).

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