Volume calibration

Calibrate the detector tube pump for proper volume measurement at least quarterly. Simply connect the pump directly to the bubble meter with a detector mbe in-line. Use a detector mbe and pump from the same manufacturer. Wet the inside of the 100 cc bubble meter with soap solution. For volume calibration, experiment to get the soap bubble even with the zero ml mark of the buret. For piston-type pumps, pull the pump handle all the way out (full pump stroke) and note where the soap bubble stops for bellows-type pumps, compress the bellows fully for automatic pumps, program the pump to take a full pump stroke. 

Figure 2. Particle diameter-retention volume calibration curves...

With SEC retention volume calibrated against sample viscosity, the viscosity of any sample can be calculated according to equation 3, without involving MW calculations and K and a values. 

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. 

Elution volume calibrations were performed using radioactive tracers of the rare earth elements and 133Ba, with atomic-absorption or flame-emission analysis of iron, sodium, potassium, calcium, and magnesium. As shown in Fig. 5.14, any barium added to the second columns is eluted at the start of the light rare earth element fraction . To ensure barium removal the sample can be put through the first column again. 

Non-linear Hydrodynamic Volume Calibration Curve. The hydrodynamic calibration curve, log. V shown in Figure lb, is generated using the commercially available narrow MWD polystyrene standards listed in Table 1 and published values (28, 29) of the Mark-Houjjink parameters K and a for polystyrene in THF a 25°C, (K=1.6 x 10, o = 0.706 for > 10,000 and K = 9.0 x 10, a = 0.5 for Mw <10,000). The experimental data points composing the non-linear calibration curve were fitted with the phenomenologically based Yau-Malone equation.(30) This equation is derived from diffusion theory and is expressed as follows ... 

Figure 6 7. Value and 95% confidence interval on the volume delivered by a nominal 10.0000-mL pipette, with different corrections applied. Cal. volume calibrated by 10 fill-and-weigh experiments. Temp volume corrected for temperature measured in the laboratory.

Thus far, the procedure is the same as that illustrated by the first three rows of plots in Figure 7 in (I). The retention volume calibration curve obtained from the PMMA test polymer samples is shown in Figure 9 in (I). 

D) Construct the HDV calibration curve in TFE from the polystyrene-generated HDV calibration curve in tetrahydrofuran in conjunction with the uTHf vs. DtFe retention volume calibration curve by one of two possible routes described below and schematically illustrated in Figure 2. 

Both of these routes involve transforming the retention volume axis uThf to t>rFE via> the retention volume calibration curve and transforming the HDV axis for PMMA in tetrahydrofuran to that for PMMA in TFE by use of the Mark-Houwink parameters for PMMA in tetrahydrofuran and in TFE. 

Route 2 (a) Using the retention volume calibration curve in conjunction with the polystyrene HDV calibration curve, construct an ap-... 

An equation can be derived relating Z A (dtFE) to Z gF ( i>thf ) As was pointed out in step C, the retention volume calibration curve relating i>thf to i>tfe was constructed by relating t>rFE to i>thf at points of equal weight percent polymer on the integral distribution of retention volume curves in tetrahydrofuran and in TFE. At these points the molecular weight of the polymer species in tetrahydrofuran is the same as the molecular weight of the polymer species in TFE. 

Q-Factor (Extended Chain Length—Retention Volume Calibration)... 

Fig. 9.2. Constant-volume tensimeter. The sample tube (enlarged view, upper left) is loaded with solid in a dry box or by sublimation from the vacuum line. The lube is evacuated, sealed, weighed, then glassblown to the tensimeter. After evacuating and flame-drying the tensimeter, the mercury level is raised and the break-seal cracked. Since the mercury serves as the cutoff to the vacuum manifold, the sample is not exposed to grease, stopcocks, or joints. This design is desirable when very long equilibration times are necessary. The mercury level is adjusted at the volume-calibrated reference point, such as A on (he diagram, if it is important to know the gas volume in the apparatus.

A dry packed column with porous material was used for the characterization according to size of the PVAc latex samples. The packing employed was CPG (Controlled Pore Glass), 2000 A, 200-400 mesh size. Deionized water with 0.8 gr/lit Aerosol O.T. (dioctyl sodium sulphosuccinate), 0.8 gr/lit sodium nitrate and 0.4 gr/lit sodium azide served as the carrier fluid under a constant flowrate. The sample loop volume was 10 pC A Beckman UV detector operating at 254 nm was connected at the column outlet to monitor particle size. A particle size-mean retention volume calibration curve was constructed from commercially available polystyrene standards. For reasons of comparison, the samples previously characterized by turbidity spectra were also characterized by SEC. A number of injections were repeated to check for the reproducibility of the method. 

The function can then be interpolated for particle sizes between those corresponding to the known latices. The relationship between particle diameter and y, the mean elution volume of the particles, is the particle size versus elution volume calibration. As discussed earlier, an HDC is calibrated using polystyrene latices, but the calibration is valid for other latices (23), and even nonlatex materials. (Colloidal gold that had been sized at 40 nm by electron microscopy was detected at 39 nm using the FlowSizer.)... 

Calibration Samples. Monodisperse polystyrene latices are available with known, narrow particle size distributions. Coefficients of variance about the mean diameter are typically less than 6% of diameter measured using electron microscopy (25). HDC typically cannot resolve differences in diameter of only 6%. Therefore, these polystyrenes are sufficiently narrow to be used as HDC calibration reference samples. However, doing so may result in incorporation of a systematic error in the particle size versus elution volume calibration, arising from known electron microscopy errors of as much as 5% for particles below 1 um (26). Therefore, accuracy can only be stated as relative to electron microscopy results for the calibration samples. FlowSizer performance specifications have been reported elsewhere (27) with diameter and mass percent results within 5% of those determined by electron microscopy for a series of these monodisperse polystyrene latices. 

Density per se is measured by weighing the sample in a volume-calibrated pycnometer or density bottle using, for example, the IUPAC standard method 2.101 (Paquot and Hautfenne, 1987). 

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