Total ionic current

Transport numbers are intended to measure the fraction of the total ionic current carried by an ion in an electrolyte as it migrates under the influence of an applied electric field. In essence, transport numbers are an indication of the relative ability of an ion to carry charge. The classical way to measure transport numbers is to pass a current between two electrodes contained in separate compartments of a two-compartment cell These two compartments are separated by a barrier that only allows the passage of ions. After a known amount of charge has passed, the composition and/or mass of the electrolytes in the two compartments are analyzed. Erom these data the fraction of the charge transported by the cation and the anion can be calculated. Transport numbers obtained by this method are measured with respect to an external reference point (i.e., the separator), and, therefore, are often referred to as external transport numbers. Two variations of the above method, the Moving Boundary method [66] and the Eiittorff method [66-69], have been used to measure cation (tR+) and anion (tx ) transport numbers in ionic liquids, and these data are listed in Table 3.6-7. 

Fig. 29.17 TIC and SIR recordings collected from blank and spiked milk samples with 2 ppb of the various tested corticosteroids. From top to bottom total ionic current m/z 313, tp 17 97/18 13 min for dexamethasone (IS) m/z 310, tp 17 99/18 14 min for dexamethasone m/z 328, tp 17 86/18 01 min for flumethasone m/z 298, tp 18 34 min for prednisolone m/z 312, tp 18 73 min for methylprednisolone m/z 296, tp 17 97 min for isoflupredone. (Reprinted from Ref. 527, with permission from Elsevier Science.)...

The fraction of the total ionic current carried by one particular species is known as the transport number,... 

A computer dedicated to mass spectrometry registers the data given out by the mass spectrometer and converts them either into values of masses and peak intensities, or into total ionic current, temperatures, acceleration potential values, and so on. It is also capable of data processing. It allows calculation of average spectra and subtraction of one spectrum from another in order to eliminate the background noise or simply to emphasize the differences between two spectra. 

A mass spectrometry detector (MSD) which consists of a low resolution mass spectrometer, cf. Chapter 16) can be placed to the outlet of the column. A fragmentation spectrum of each eluted compound is obtained. From the total ionic current... 

AGC settings, and a rapid rf scan to get a rough measurement of the total ionic current. All... 

Recordings of the elementary contributions to the total ionic current in squid giant axons due to single potassium channels have been recently obtained. These measurements confirm the validity of... 

In an inorganic compound the total ionic current density, iion. is given by the sum of the current densities of anions, ian> and the cations, icat- From our previously derived expressions for partial current densities we thus obtain... 

Due to the creation/annihilation reaction of Frenkel pairs, Equations (7.1) and (7.4) can be combined to yield the total ionic current density, jj ... 

An important characteristic of the efficiency of electrochemical cell is the value of the current efficiency coefficient (r ). Current efficiency (i]) can be defined from the value of the oxygen ionic current (Ino) due to the oxygen from decomposed NO gas (see eq.2) and a total ionic current flux through the cell (I = Ino + I02) as ... 

TIC indicates total ionic current. RIC, meaning reconstituted ionic current, is also used. The third dimension, perpendicular to the plan of the paper, corresponds to the mass spectrum s trace (ion current as a function of m/z ratio). For practical reasons, the chromatograms are never visualized as in Figure 5.2. They are visualized in... 

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