Separation number

SEPARATION NUMBER. As an extension of the term separation factor (S) discussed above, we also can calculate a separation number (nsep) as another way of describing column efficiency (34). By separation number we mean the number of possible peaks which appear between two n-paraffin peaks with consecutive carbon numbers. It may be calculated by 

This equation may be used to characterize capillary columns or when employing programmed pressure or temperature conditions for packed columns. 

The value of SN depends on the alkanes used for the calculation, these are therefore specified with any value of SN quoted. 

For low k veilues resolution increases very rapidly with increasing k. At large k values the term C 1 and a further k increase will not improve resolution. Thus, the optimum veilues of k lie in the range 1 k 10. The minimum analysis time for open tubular columns is achieved under the conditions where k is about 1-2. As a rule, capacity is not a critical parameter in ALOT columns. 

Separation is also characterized by separation number (S/y) or Trennzahl (TZ). The latter is defined as the maximum number of peaks of equal heights one can place between the peaks of two reference compounds assuming a resolution of 1.0 between each of these peaks [77]. 

Separation number is defined as the number of component peaks which can be placed between the peaks of two consecutive homologous standards with z and (z + 1) carbon atoms and can be separated with resolution of ff = 1.77, 

The SN of a column is dependent on the nature of the stationary phase, on the column length, temperature and carrier gas flow rate. The separation number is the only parameter of column efficiency which can be determined under temperature progreimming conditions [50]. 

Equation (3-23) can be eirreinged for two peaks (located close to each other in the chromatogram) to predict the number of theoretical plates required to give the separation [78, 79]  

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Schmidt number = p D flow-line separation number = D j inertial separation number = U /U /... 

Gardner Color. Color measurement is obtained by comparing the sample with 18 separately numbered Gardner color standards. These are convenientiy mounted as glass disks on wheels. The entire apparatus, consisting of two wheels containing nine disks each, a case to enclose the wheels, and a slot ia the case for the sample, is commercially known as the HeUige Comparator (3). 

Patis Numheting. Parts shall he completely identified with a numerical system (no alphabetical letters) to facilitate parts inventory control and stocking. Each part shall he properly identified by a separate number, and those parts that are identical shall have the same number to effect minimum spare parts inventory. 

N r Electrostatic-attraction separation number Dimensionless Dimensionless ... 

And introducing the ratio of accelerations, = ag/g, where indicates the relative strength of acceleration, ag, with respect to the gravitational acceleration g. This is known as the separation number. The LHS of equation 60 contains a Reynolds number group raised to the second power and the drag coefficient. Hence, the equation may be written entirely in terms of dimensionless numbers ... 

For this reason we want to determine the number of centric and bicentric trees separately. Numbers of centric trees will be distinguished from those of bicentric trees by primes and double primes, respectively. Of the p, a, T, respectively, free trees are... 

Use hyphens to separate the different prefixes, and use commas to separate numbers. If two or more different substituents are present, cite them in alphabetical order. If two or more identical substituents are present, use one of the multiplier prefixes d, fn -, tetra-, and so forth, but don t use these prefixes for alphabetizing. Full names for some of the examples we have been using follow. 

The efficiency of an open tubular column can be measured in several ways the most widely used methods are the number of theoretical plates (n), the nu3aber of effective theoretical plates (N), the height equivalent to a theoretical plate (HETP) or effective plate, the coating efficiency and the separation number (SM). No single method is ideal, standardization is lacking and... 

The potential of a chromatographic system to provide a certain separation can be estimated from its separation number, S SH, also referred to as the spot capacity in TLC. The separation j nund>er in TLC is defined as the number of spots that can be. completely separated (R, > 1) between R 0 and R, ° 1 (6). It is calculated in an approximate form by equation (7.16) and morej exactly by equation (7.17) with b, and b, as defined in Figure 7.4. 

The colvooi efficiency is determined by the separation number tained for the methyl esters of decanoic, undecanoic, and dodecanoic acids (E o> 12> A relative difference in the molecular sizes of the homologous pairs decreases with increasing molecular size, the first pair of methyl esters (E, /E t) provides a separation number value that is about 8% higher than that of the... 

Other state differences can be too subtle to record effectively on a statechart — for example, there is a difference between a book that has been loaned five times and one that has been out on six occasions but unless the library s loan policy changes qualitatively at that number, it would be pointless, though valid, to draw separate states for loaned more (or less) than five times , and still more so to draw separate states for each separate number of times out. 

We separate numbers from other numbers by commas, and we separate numbers from letters by a dash. 

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