Unbuffered Media

The use of aprotic. (and therefore totally unbuffered media in analytical studies of sulphones may lead to wrong conclusions. The voltammetric determination of the benzyl phenyl sulphone26 was aimed to clearly exemplify the deactivation process in dry dimethylformamide. So, in aprotic or low acidity solvents, two main steps (equivalent to the transfer of one electron each) can be seen (Figure 6, curve 1). These two steps were shown at the potential of the cleavage (— 1.7 volt) to correspond, for acidic sulphones, to the following processes ... 

II. DISSOLUTION OF ACIDIC AND BASIC DRUGS IN UNBUFFERED MEDIA... 

Q t r, obtained for benzene derivatives bearing the same reducible group R at pH 5—8 and in unbuffered media for pH-independent systems... 

Fig. 30. The range of potentials in which the half-wave potentials of monosubsti-tuted and of most of the disubstituted benzenoid compounds can be expected, provided that the reduction of the substituted compound follows the same path as that for the parent compound of the particular reaction series. For pH 5—8 and unbuffered media...

The following table lists the polarographic Em potential ranges (in V vs. SCE) obtained at pH 5-9 in unbuffered media in the reduction of benzene derivatives.1... 

The polarographic behavior of D-glucurono-6,3-lactone " and d-mannurono-6,3-lactone was also studied, in order to develop analytical methods for their detection. The polarographic waves of these lactones appear only in unbuffered media, among which, 0.2 M aqueous lithium chloride solution proved to be the best base electrolyte, with 0.005%... 

Initial studies on the removal of metal ions from an aqueous stream by microemulsion liquid membranes were focused on copper [16]. The copper was successfully separated from both buffered and unbuffered media by using a microemulsion liquid membrane similar to the one employed for acetic acid but modified to incorporate a liquid metal ion exchanger. This work was very preliminary in nature but did show the capability of microemulsions to separate metal ions from solution. 

Aqueous solutions of many salts and/or complexing agents at various pH. Buffered and unbuffered media. 

Species of Dekkera/Brettanomyces produce large amounts of acetic acid when grown on glucose (Freer, 2002). In fact, acetic acid production can be sufficient to inhibit and eventually kill cultures maintained on unbuffered media. Thus, routine laboratory maintenance media contains 2% w/v calcium carbonate to buffer against the acids produced (Section 13.5). However, Brettanomyces tends to a slow growing yeast, often requiring several days for colonies to appear on solidified media. 

Solubility of Poorly Soluble Salts in Unbuffered Media. . 642... 

Knight, S. A. B. Dancis, A. Reduction of 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2f7-tetrazolium-5-carboxanilide inner salt (XTT) is dependent on CaFRElO ferric reductase for Candida albicans grown in unbuffered media. Microbiology 2006, 152, 2301-2308. 

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