Salt substitute, sodium Sample

Description of Method. Salt substitutes, which are used in place of table salt for individuals on a low-sodium diet, contain KCI. Depending on the brand, fumaric acid, calcium hydrogen phosphate, or potassium tartrate also may be present. Typically, the concentration of sodium in a salt substitute is about 100 ppm. The concentration of sodium is easily determined by flame atomic emission. Because it is difficult to match the matrix of the standards to that of the sample, the analysis is accomplished by the method of standard additions. 

The concentration of sodium in the standard addition samples is determined from the absolute value of the x-intercept (see Figure 5.7b) thus, substituting zero for the emission intensity gives the concentration of sodium as 1.44 ppm. The concentration of sodium in the salt substitute, therefore, is... 

The 6-0-benzyl protected dienes 4a and 4P were prepared from the known (10) 1,2-O-isopropylidene-a-D-glucofuranose (Scheme 3). In fhis case, evidence for the intermediate formation of aldehyde 23a in the Wittig reaction conducted at room temperature was obtained by comparison with an authentic sample of aldehyde 23a obtained directly from compound 21 (a + P) using P-tosyloxy acrolein prepaid in situ from the sodium salt of malonaldehyde and tosyl chloride in THF. Finally, the methyl substituted derivatives 5a and SP were prepared as for the parent dienes 2a and 2p according to Scheme 1 using the corresponding 2-methyl substituted sodium salt of malonaldehyde (72). 

Synthesis of the rhodium(I) complexes of TTP and TTX is not as straightforward as, for example, that of the Rh(I) complexes of phosphines. Substitution reactions, such as the refluxing of [Rh(l,5-cyclo-octadiene)2Cl]2 with TTP, generally failed. Also the Rh(III) in RhCls 3H2O is not simultaneously reduced and chelated by TTP (JO). The only successful routes that we foimd involve the reduction of the previously characterized Rh(III) complexes. Voltammetry in acetonitrile solution on [Rh(TTP)Cl2]Cl showed a single cathodic process at —0.72 V (vs. AgVAgCl) which represents a two-electron reduction. Small samples of the Rh(I) salt were prepared by electrolysis, but reduction with sodium borohydride in methanol was used to prepare most of the salts reported here. 

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