LC chromatogram

Referring again to the retention of a solute on a thin layer plate depicted in figure 2 and comparing this with a normal GC or LC chromatogram, then the distance (y - x)... 

Gianesello et al. (120) described the determination of the bronchodilator brox-aterol in plasma by on-line LC-GC. After deproteination and extraction, the LC separation was carried out by using a mixture of -pentane and diethyl ether (55 45 (vol/vol) as mobile phase. A small cut of the LC chromatogram (shown in Figure 11.9(a)) was introduced at 85 °C into the GC via so-called concurrent solvent evaporation. Figure 11.9(b) demonstrates that a detection limit of about 0.03 ng/ml was obtained. A fully automated LC-GC instrument was described by Munari and Grob (121) and its applicability was demonstrated by the determination of heroin metabo-... 

Figure 13.10 LC-LC chromatogram of a surface water sample spiked at 2 p.g 1 with ati azine, and its metabolites (registered at 220 nm). Conditions volume of sample injected, 2 ml clean-up time, 2.60 min ti ansfer time, 4.2 min The blank was subtracted. Peak identification is as follows 1, DIA 2, HA 3, DEA 4, atrazine. Reprinted from Journal of Chromatography, A 778, F. Hernandez et al, New method for the rapid detemiination of triazine herbicides and some of thek main metabolites in water by using coupled-column liquid cliromatography and large volume injection , pp. 171-181, copyright 1997, with permission from Elsevier Science.

Fig. 2.3.2. LC chromatograms of a standard solution containing LAS and DATS obtained by eluting them on (a) Cg column and (b) Clg column. In both cases, peaks 1-4 are, respectively, for C10-C13 DATS, while peaks 5-8 are, respectively, for C10-C13 LAS. Reprinted with permission from Ref. [31] 2001 Elsevier.

Fig. 3.82. LC/ESI-MS analysis of reacted RB4 (500 mg/1) in negative ion mode of operation total LC chromatogram (a) and enlarged chromatogram from 25 to 30 min retention time (b). Reprinted with permission from W. J. Epolito et al. [145],...

Figure 6.36 500 MHz H NMR spectra obtained during a stop-flow LC-NMR experiment on a 1 mg injection of a crude sample of a drug compound, (a) LC chromatogram, (b) spectram corresponding to the parent bulk drug compound acquhed for 64 transients and (c) to the impurity peak RRT 0.87 (—3% by area), acquhed for 1024 transients. NOESY-type presaturation was used to suppress the solvent resonances. Bruker DRX500 H/ C 4-mm z-gradient probe with a 120 pi active cell volume.

Figure 3. LC chromatogram of carbonyls collected on a DNPH-impregnated silica gel cartridge. Peak identities 1, DNPH 2, formaldehyde 3, acetaldehyde 4, acrolein 5, acetone 6, propionaldehyde 7, x-acrolein 8y crotonaldehyde 9, butyraldehyde and 10, benzaldehyde. (Reproduced with permission from reference8. Copyright 1992.)...

Figure F3.1.1 Isocratic gradient LC chromatogram of betacyanin pigments. Peak A betanin peak B isobetanin peak C betanidin, and peak D isobetanidin. Adopted from Schwartz and von Elbe (1980).

Fig. 34 (a) Typical LC chromatogram for soybean oil as reference material for the identification of... 

Figure 2.4 (a) LC chromatogram of fat extracted from an irradiated chicken. The... 

Figure 6.7 LC chromatograms with photodiode array detection at two different wavelengths of the leachate sample (for peak assignment, see Table 6.3). Reprinted from Benfenati, E., Pierucci, P., Fanelli, R., Preiss, A., Godejohann, M., Astratov, M., Levsen, K., and Barcelo, D.,. /. Chromatogr., A, 831, 243-256, copyright (1999), with permission of Elsevier Science...

Figure 6.15 LC chromatogram of the hydrolysis products from the first step of simulated waste water treatment of Remazol Black 5. Conditions column, LiChrospher RP 18e, 250 x 4.0mm, 5 eluent, A - 20mM NH4COOH in CH3CN/D20 (70/30), B - 20mM NH4COOH in CH3CN/D2O (10/90) gradient, t = Omin A/B (10/90), / = 15min A/B (70/30) flow, 0.8 ml/min...

Overall there are 2n — n — 1 = 1013 variations of different two-, three-, four- up to the only one possible ten-component reaction mixture. From these 1013 different combinations of starting materials, several gave the expected and known MCR products. Using a minimum peak height requirement of 30% (compared to the sum of all peaks in the respective LC chromatogram) for a novel and unknown reaction product, unique MCR products were found. For example, the expected Ugi 4-CR product was re-found by this systematic search method (Figure 10.1). 

Figure 6.9. LC chromatograms and ratiograms using UV detection at two wavelengths (255 and 280 nm) with four different mobile phases. Reprinted with permission from A. C. J. H. Drouen, H. A. H. Billiet, and L. De Galan, Anal. Chem. 1984, 56, 971. Copyright 1984, American Chemical Society.

Fig. 1 Capillary LC chromatogram of a river water solid-phase extract containing PAHs. Column fused silica (20 cm X 0.25 mm) HjO home-packed with RP-18 (5 tm). Mobile phase ACN/H20 (75 25), flow rate 4 /xL/min, UV detection at 254 nm. Compound identity 1 = fenanthrene, 2 = anthracene, 3 = fluoranthene, 4 = pyrene, 5 = crysene.

Fig. 7 LC chromatograms of Irgafos 168, Irganox 1076 and of the degradation product from Irgafos 168, extracted by MAE from PE. Permission for reproduction from Elsevier [71]...

Figure 1. LC chromatograms (UV, 254 nm) representing (A) SF extract of a garlic homogenate stored at room temperature for 10 min and (B) SF extract of a garlic homogenate stored at room temperature for 2 h.

Figure 13 LCxGC-FID bubble plot relative to an experiment carried out on edible oil TAGS. The x-axis defines the LC fraction number, while the y-axis defines the TAG carbon number. The reconstructed LC chromatogram shows the saturated, mono-, di-, tri-, and higher-than-tri-unsaturated TAGs [48].

Fig. 1. LC chromatograms of edible oils showing a high degree of variation in baseline.

Fig. 3. An LC chromatogram before (blue) and after (red) baseline correction.

There are multiple ways to spot samples. For instance, the sample and matrix may be mixed before spotting, or either solution may be spotted first with or without drying in-between. Often it is worth trying multiple approaches to sample loading to see which provides the best signal-to-noise ratio. Robotic placement of samples is applicable for the eluates from nano-LC. The signals from automated, sequential analysis of hundreds of spots replicate LC chromatograms. In these applications the MALDl plate is often pretreated with the matrix solution to provide an appropriate surface for the analytes. 

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