Contents 3 Ideal sampling

An ideal sample for bottle testing (discussed in the next section) is a stable composite emulsion containing 30% water. When a composite sample is not suitable, as evidenced by a lack of stability, chemical contamination, or low water cut (content), a composite of several wellhead samples must be used. [ Cut refers to the process of determining the BS W (basic sediment and water) content of the oil phase in a sample of produced fluid. Cuts can be taken from the top, middle, or interface of the oil phase.]... 

The chemiluminescent detection method has also been employed for monitoring the glucose content of dialysate. This detection mode requires the addition of reagents such as luminol to obtain the analytical signal, and this requires a more complex system with additional pump lines, mixing coils, etc. Flow injection is considered the ideal sample introduction mode for chemiluminescence [134], but this makes the measuring system rather cumbersome and not easy to miniaturize. 

Evidently the ideal sampling depth from the viewpoint of a constant Rn signal is 2 m or more. In practice such a depth is seldom attained because of practical difficulties. Quite often overburden thicknesses are less than 2 m, and as was shown above, variation in depth from site-to-site in near-surface surveys can have a pronounced effect on the soil-gas Rn concentration, apart from any meteorological variations. The meteorological variables responsible for these large changes in the soil-gas Rn concentration are barometric pressure, moisture content of soil, wind, temperature, convection and Earth tremors. 

Similar to other compoimds, polymer may be real or ideal product. In the first case, structure and composition of the polymer, usually produced by an industrial or semi-industrial way, represents a compromise of production costs and competitive ability of the product by its quality. Most frequently, ideal or similar product is obtained in laboratory in vitro, using pure monomers and optimal technique. The latter should provide the absence of labile structures. However, quantity of ideal samples is limited, so it is not enough for performing pilot studies of aging and stabilization, in which the effect of these factors on macroscopic properties of polymers are considered. Therefore, a standard must be selected among industrial PSF. It should approach the ideal polysulfone in purity and the presence of labile structures. We mean not full absence of the mentioned defect, but their minimal content that causes no significant effect on thermal behavior. 

Conclusions. A Mossbauer sample with a low content of the resonance nuclide has ideal thickness when it attenuates the incident radiation by ca. 63-85% (/ie t = 1-2, C /Co e - e ). However, the optimization should be subordinated to the requirement of a thin absorber having an effective thickness / < 1 to avoid excessive line broadening. 

The performance curve presents graphically the relationship between the probability of obtaining positive results PPRy i.e. x > xLSp on the one hand and the content x within a region around the limit of discrimination xDIS on the other. For its construction there must be carried out a larger number of tests (n > 30) with samples of well-known content (as a rule realized by doped blank samples). As a result, curves such as shown in Fig. 4.10 will be obtained, where Fig. 4.10a shows the ideal shape that can only be imagined theoretically if infinitely exact decisions, corresponding to measured values characterized by an infinitely small confidence interval, exist. 

Electron paramagnetic resonance (EPR) spectroscopy is yet another diagnostic tool for the detection of isomorphous substitution of Ti. Its sensitivity is very high, and investigations can be performed with samples even with very low contents of paramagnetic species. The spectra and g parameters are sensitive to the local structure and associated molecular distortions. Hence, it is an ideal tool to characterize Ti in titanosilicates. Ti in the + 4 oxidation state in titanosilicates is diamagnetic and hence EPR-silent. Upon contacting with CO or H2 at elevated... 

A control sample is a sample for which the concentrations of the test analyte is known and which is treated in an identical manner to the test samples. It should ideally be of a similar overall composition to the test samples in order to show similar physical and analytical features. For instance, if serum samples are being analysed for their glucose content, the control sample should also be serum with a known concentration of glucose. A control sample will be one of many aliquots of a larger sample, stored under suitable conditions and for which the between batch mean and standard deviation of many replicates have been determined. It may be prepared within the laboratory or purchased from an external supplier. Although values are often stated for commercially available control samples, it is essential that the mean and standard deviation are determined from replicate analyses within each particular laboratory. 

Names are assigned to members of this series somewhat arbitrarily. For example, the term actinolite may be used when the magnesium content of the sample is as low as (Mgo.iFeo, ) and when the magnesium content is well above that of the ideal formula (20% Mg in place of Fe). 

Ideally, for purified or partially purified protein, the protein standard should have an aromatic amino acid content similar to that of the sample protein. For the total protein of a crude lysate, bovine serum albumin (BSA) is a commonly used standard for spectrophotometric quantitation of protein concentration. A 3 mg/ml solution of BSA should have an A280 of 1.98, based on an A2S0 of 6.61 for a 1% (w/v) solution. 

---