Eluate curves

The column system was connected to an in-line monitoring arrangement. Table IV presents the detectors used for in-line monitoring. Eluate curves were drawn on the recorders. An eluate curve of separated Am and Cm based on Ge(Li) detector is shown in Fig. 4. With this in-line monitoring arrangement, pure products of Am and Cm were collected. 

Differential ionic chromatography. In a potentiometric method for recording ion-exchange elution curves, a dual-channel membrane cell is used as a differential detector186 for following the eluate composition in comparison with the eluent. In the chromatography of alkali metal ions over a... 

The elution volume of a solute is determined mainly by its relative molecular mass and it has been shown that the elution volume is approximately a linear function of the logarithm of the relative molecular mass. It is possible to determine the relative molecular mass of a test molecule using a calibration curve prepared from the elution volumes of several reference substances of known relative molecular mass. This should be done using the same column and conditions (Figure 3.37) and in practice it may be possible to calibrate the column and separate the test substance at the same time by incorporating the reference compounds in the sample. Such a method is rapid and inexpensive and does not demand a highly purified sample, provided that there is a specific method for detecting the molecule in the eluate. 

Fig. 2.26 Plot of the DBQ (Drug, D)/CMVP A144L (Protein, P) molar ratios for the incubated concentrations as a function of the non-covalently bound concentrations as determined in the titration study of the GPC spin column eluates assayed by ESI-MS (see Table 2.5). The shape of the curve indicates that up to three drugs bind non-covalently and non-specifically to CMVP A144L.

Spectra of nitric oxide reductase from Paracoccus denitrificans (batch eluate). Solid curve, enzyme as prepared (oxidized) dashed and dtit-dashed curves, reduced with a small excess of dithionite. Inset solid curve shows the second derivative of the dashed curve. The protein concentration was about 200 /ng/ml. From Dermastia et al. (1991). 

In work published in 1989, Hylemon et al. used cholesterol oxidase to convert 7a-hydroxycholesterol to 7a-hydroxy-4-cholesten-3-one. Cholesterol that remained was converted to 4-cholesten-3-one. 7/3-Cholesterol, which was added as an internal steroid recovery standard, was oxidized to 7/3-hydroxy-4-cholesten-3-one. These steroid products were analyzed by Qg reversed-phase chromatography on an Altex Ultrasil-ODS column (4.6 mm x 25 cm) using 70 30 (v/v) mixture of acetonitrile and methanol (Fig. 9.83). The eluate was monitored at 240 nm, and the amount of product determined from a calibration curve. 

The quinoxalinol derivative obtained by reaction of pyruvate with o-phenylenediamine is chromatographed on a ChromSphere Q8 column (3 mm X 100 mm, 5 pim) at a flow rate of 0.4 mL/min using a mobile phase of 45% methanol, 1% acetic acid, and 54% water. The eluate was monitored by a fluorescence spectrometer using excitation and emission wavelengths of 336 and 420 nm, respectively. Calibration curves were constructed by adding known amounts of pyruvate to cytosolic fractions and carrying them through the derivatization and analysis procedures. 

Alternatively, the nickel content in each fraction can be determined gravimctrically and an elution curve obtained by plotting a graph of volume of eluate against nickel concentration. 

Recovery and Analysis of Abamectin Residues. Sample preparation was a modification of the initial steps of Merck Co. Method 8001 (9). Cg solid-phase extraction columns (Fisher Prep-Sep, 300 mg resin) were conditioned by consecutive washes with hexane, ethyl acetate, methanol, acetonitrile, and water (20 ml. each). Samples (100 ml of glass-distilled water) were spiked with various amounts of abamectin, adjusted to 25% (v/v) acetonitrile, and applied to the columns. The columns were washed with 10 ml of water, and then the abamectin was eluted in 12 ml of acetonitrile. The eluates were evaporated to 1.0 ml at 70s under nitrogen. Dilutions of these samples were made in PBS-Tween-20% acetonitrile, and mixed with equal volumes of MAb B11C2.1 (1 200 in the same buffer) in sealed 1.4 ml polypropylene tubes. After incubation for 2 hr to about 14 hr (overnight) at room temperature, replicate aliquots (100 pi) were transferred to Immukm 2 EIA wells coated with 25 ng ivermectin 4"-hemisuccinate-CON for the standard competition EIA. Standard curves consisted of 8 dilutions of abamectin, from 0.01 ppb to 500 ppb, in triplicate. 

Absorption and CD spectra of the [Coa(gly)(tacn)]-type complexes — The absorption spectrum of the racemic anmine complex and the CD spectra of the resolved isomers are shown in Figure 13, showing that the CD curves are mirror images of each other. Since the same situation is encountered in the resolved pairs of other complexes, the CD spectra for only the isomers obtained from the earlier eluates are illustrated together with the absorption spectra in Figures 14-17. The spectra for the hydroxo complex, [Go (OH) (gly) (tacn) ]+, were those measured with an aqueous solution of the aqua complex at pi 9.0. 

Figure 5.15 shows how the uranium concentration of the eluate changes with bed volumes of eluate for three commonly used eluants, as reported by Greer et al. [Gl]. The area under each curve represents the original, uniform uranium concentration of the bed, apparently around 80 g UsOg/liter in this example. 

GC/MS. About one-third of the pre-application samples and nearly all post-application samples were analyzed by GC/MS for 11 herbicides and 2 metabolites of atrazine. Herbicides and metabolites were Isolated by solid- phase extraction and analyzed by GC/MS (14). GC/MS analyses of the eluates were performed on a Hewlett Packard model 5890A gas chromatograph (Palo Alto, Calif.) and a 5970A mass selective detector (MSB). Thirty-one ions were selectively monitored, and the base-peak ion current was measured for the quantification curve as a function of the response of the mass 188 Ion of d Qphenanthrene. Confirmation was based upon... 

Metal-ion uptake in a dynamic system Sorption experiments in a dynamic system were carried out using a glass column (length 10 cm, internal diameter 1.2 cm) filled with 1.0 g resin. The resin was washed with distilled-deionized water (10 bed volumes), then a solution containing 40 ppm Cu was passed through at a flow rate of 3 mLmin . For determination of the breakthrough curve, the eluate from the column was collected in 50 mL fractions and the copper cation concentration was determined by atomic absorption spectroscopy. 

FIGURE 6.24 Example of an ii-curve. (1) Injection, (2) first tracer molecules in eluate, (3) maximum tracer concentration, (4) last tracer molecules in eluate. 

Figure 11. Separation of hemoglobin preparation by electrofocusing in the same apparatus shown in Fig. 10 showing a curve from the same run. The curve with the peaks shows the absorption in the eluate at 260 nm. It is obtained from one run in a series of consecutive experiments with the aim of getting a more narrow pH-gradient and a more refined separation of sample compounds in every step. The steadily falling curve is plot of the pH-gradient. The pi values shown at the various peaks were read from the pH-gradient curve. The electrofocusing was run at +4°C as were the pH readings.

Figures 1 A and B. 1 A compares the T3 and T4 standard curves with serial dilutions of eluates obtained from embryo-trophoblasts (E-T), embryonic (E) placental (P) and amniotic fluid (AF) samples obtained at different gestational ages in the rat, shown in the inset. 1 B shows similar curves with extracts from human fetal brains, between 10 and 16 weeks of gestation. 

Figure 1 Ideal elution curve from an ion-exchange column of a di-isotopic single solute ion. (A) The isotopic ratio Rasa function of the elution volume V. (B) Total concentration Cof the ion in the eluate as a function of V.

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