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Conventional calibration curves

The GPCV2 equations were developed for conventional log(MW) vs. retention volume calibrations. When used in conjunction with a universal calibration, the slope term (Do) must be corrected for the different molecular size/weignt relationships of the calibrants and the samples as derived in the following equations. To understand this correction, consider the conventional calibration curve that could be created from the universal calibration data. [Pg.126]

A compound or element added to all calibration standards and samples in a constant known amount. Sometimes a major constituent of the samples to be analysed can be used for this purpose. Instead of preparing a conventional calibration curve of instrument response as a function of analyte mass, volume or concentration, a response ratio is computed for each calibration standard and sample, i.e. the instrument response for the analyte is divided by the corresponding response for the fixed amount of added internal standard. Ideally, the latter will be the same for each pair of measurements but variations in experimental conditions may alter the responses of both analyte and internal standard. However, their ratio should be unaffected and should therefore be a more reliable function of... [Pg.620]

Alternatively, the predicted cumulative PSD can be converted to a conventional calibration curve for comparison with... [Pg.182]

A Calgon in-house computer simulation program developed by Min and Cha (48) has been applied to construct a conventional calibration curve. This program is written in Fortran. It needs two standards for a linear fit and four... [Pg.252]

Molecular weights were determined by gel permeation chromatography (GPC) using a Waters HPLC system equipped with noodel 510 pump. Waters model 717 autosampler, model 410 refractive index detector, and model T-50/T-60 detector from Viscotek Corporation with 500, 10, 10 and 10 A ultrastyragel columns in series. Trisec GPC software version 3 was used for calculations. Chloroform was used as the eluent at a flow rate of 1.0 mL per minute. Sanq>le concentrations of 0.2 % wt/vol and injection volumes of 100 )XL were used. Molecular weights were determined based on a conventional calibration curve generate by narrow molecular weight polystyrene standards obtained from Aldrich chemical conq>any. [Pg.408]

The results as illustrated in Fig. 4 are not as scattered as might first appear, since the discharge coefficient scale is expanded. The conventional calibration curve (shown in Fig. 5) approaches very nearly the theoretical curve for this Venturi. [Pg.288]

The use of hexafluoroisopropanol (HFIP) as an SEC eluent has become popular for the analysis of polyesters and polyamides. Conventional PS/DVB-based SEC columns have been widely used for HFIP applications, although the relatively high polarity of HFIP has led to some practical difficulties (1) the SEC calibration curve can exhibit excessive curvature, (2) polydisperse samples can exhibit dislocations or shoulders on the peaks, and (3) low molecular weight resolution can be lost, causing additive/system peaks to coelute with the low molecular weight tail of the polymer distribution... [Pg.359]

In SEC, universal calibration is often utilized to characterize a molecular weight distribution. For a universal calibration curve, one must determine the product of log(intrinsic viscosity molecular weight), or log([7j] M). The universal calibration method originally described by Benoit et al. (9) employs the hydro-dynamic radius or volume, the product of [tj] M as the separation parameter. The calibration curves for a variety of polymers will converge toward a single curve when plotted as log([7j] M) versus elution volume (VJ, rather than plotted the conventional way as log(M) versus V, (5). Universal calibration behavior is highly dependent on the absence of any secondary separation effects. Most failures of universal calibration are normally due to the absence of a pure size exclusion mechanism. [Pg.565]

Whereas the use of conventional fast atom bombardment (FAB) in the analysis of polymer/additive extracts has been reported (see Section 6.2.4), the need for a glycerol (or other polar) matrix might render FAB-MS analysis of a dissolved polymer/additive system rather unattractive (high chemical background, high level of matrix-, solvent- and polymer-related ions, complicated spectra). Yet, in selected cases the method has proved quite successful. Lay and Miller [53] have developed an alternative method to the use of sample extraction, cleanup, followed by GC in the quantitative analysis of PVC/DEHP with plasticiser levels as typically found in consumer products (ca. 30 %). The method relied on addition of the internal standard didecylphthalate (DDP) to a THF solution of the PVC sample with FAB-MS quantitation based on the relative signal levels of the [MH]+ ions of DEHP and DDP obtained from full-scan spectra, and on the use of a calibration curve (intensity ratio m/z 391/447 vs. mg DEHP/mg DDP). No FAB-matrix was added. No ions associated with the bulk of the PVC polymer were observed. It was... [Pg.702]

Quantitative analysis demands that an analytical measurement can be accurately and reliably related to the composition of the sample in a strict proportionality (p. 2). The complexity of relationships, especially for instrumental techniques, means that the proportionalities need to be practically established in calibration procedures. For a typical simple calibration, a range of standards is prepared containing varying amounts of the analyte. These are then analysed by the standard method and a calibration curve of signal us amount of analyte is plotted. Results for unknowns are then interpolated from this graph (Figure 2.7). An important convention is... [Pg.16]

The output of the system was calibrated against a conventional type K thermocouple and a calibration curve, resulting from using such a laser diode with a 670-nm... [Pg.362]

P-outine chemical analysis. This implies analysis of many samples, and use of calibration curves is an economic necessity. In general, the two-standard method, with standards bracketing each sample analyzed, is economical for the analysis of up to about 10 samples. Conventional least squares curve of best fit procedures are economical for analysis of 10 to 500 samples. The procedures described here are cost effective for the analysis of 500 samples or more. [Pg.115]

Determination of Pore Size Distributions. The shape and range of a GPC calibration curve are, in part, a reflection of the pore size distribution (PSD) of the column packing material. A consideration of the nature of PSDs for the ULTRASTYRAGEL columns to be used in this work is therefore appropriate. The classical techniques for the measurement of PSDs are mercury porisimetry and capillary condensation. The equipment required to perform these measurements is expensive to own and maintain and the experiments are tedious. In addition, it is not clear that these methods can be effectively applied to swellable gels such as the styrene-divinylbenzene copolymer used in ULTRASTYRAGEL columns. Both of the classical techniques are applied to dry solids, but a significant portion of the pore structure of the gel is collapsed in this state. For this reason, it would be desirable to find a way to determine the PSD from measurements taken on gels in the swollen state in which they are normally used, e.g. a conventional packed GPC column. [Pg.172]

The idea of calorimetry is based on the chemical reaction characteristic of molecules. The calorimetry method does not allow absolute measurements, as is the case, for example, with volumetric methods. The results given by unknown compounds must be compared with the calibration curve prepared from known amounts of pure standard compounds under the same conditions. In practical laboratory work there are very different applications of this method, because there is no general rule for reporting results of calorimetric determinations. A conventional spectrophotometry is used with a calorimeter. The limitations of many calometric procedures lie in the chemical reactions upon which these procedures are based rather than upon the instruments available . This method was first adapted for quinolizidine alkaloid analysis in 1940 by Prudhomme, and subsequently used and developed by many authors. In particular, a calorimetric microdetermination of lupine and sparteine was developed in 1957. The micromethod depends upon the reaction between the alkaloid bases and methyl range in chloroform. [Pg.132]

Erom Equations 12.46 and 12.47, one sees that ThEEE retention is related to (l/5j), but not specifically to a conventional analyte property, such as molar mass M or particle diameter d. However, since HSj depends on M or d, it also mediates the dependence between R and M or d. At constant Tq conditions, the relationship between X, M, and AT can be experimentally exploited by using standards. Eor instance, in polymers mass characterization, monodisperse or polydisperse standards can be employed for a specific polymer-solvent system. Once the relationship X vs. M, that is, the so-called calibration curve, is obtained, it is universal, that is, valid for any ThFFF instrument [3]. A typical calibration function, which relates the instrumental response to analyte property (in this case M), is... [Pg.349]

Determining Calibration Curves frcm Polydisperse Samples. In conventional SEC interpretation, narrow molecular weight distribution standards are needed for calibration purposes. Nonlinear regression has enabled polydisperse scimples to be used. A variety of methods... [Pg.205]


See other pages where Conventional calibration curves is mentioned: [Pg.182]    [Pg.182]    [Pg.214]    [Pg.51]    [Pg.270]    [Pg.287]    [Pg.43]    [Pg.44]    [Pg.143]    [Pg.226]    [Pg.182]    [Pg.182]    [Pg.214]    [Pg.51]    [Pg.270]    [Pg.287]    [Pg.43]    [Pg.44]    [Pg.143]    [Pg.226]    [Pg.360]    [Pg.2]    [Pg.732]    [Pg.290]    [Pg.224]    [Pg.266]    [Pg.529]    [Pg.105]    [Pg.110]    [Pg.439]    [Pg.49]    [Pg.286]    [Pg.62]    [Pg.160]    [Pg.228]    [Pg.104]    [Pg.205]    [Pg.205]    [Pg.452]    [Pg.266]   
See also in sourсe #XX -- [ Pg.44 , Pg.44 ]




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Calibration curve

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