Bi vitamin

Description of Method. The water-soluble vitamins Bi (thiamine hydrochloride), B2 (riboflavin), B3 (niacinamide), and Be (pyridoxine hydrochloride) may be determined by CZE using a pH 9 sodium tetraborate/sodlum dIhydrogen phosphate buffer or by MEKC using the same buffer with the addition of sodium dodecyl-sulfate. Detection Is by UV absorption at 200 nm. An Internal standard of o-ethoxybenzamide Is used to standardize the method. 

Vitamin Bi is a cation and must, therefore, elute before the neutral species methanol thus it elutes first at 3.41 min. Vitamin B3 is a neutral species and should elute with methanol at 4.69 min. The remaining two B vitamins are weak acids that partially ionize in the pH 9 buffer. Of the two, vitamin Be is the stronger acid and is ionized (as the anion) to a greater extent. Vitamin Be, therefore, is the last of the vitamins to elute. 

The order of elution when using MEKC is vitamin B3 (5.58 min), vitamin Be (6.59 min), vitamin 82 (8.81 min), and vitamin Bi (11.21 min). What conclusions can you make about the solubility of the B vitamins in the sodium dodecylsulfate micelles ... 

A quantitative analysis for vitamin Bi was carried out using this procedure. When a solution of 100.0 ppm Bi and 100.0 ppm o-ethoxybenzamide was analyzed, the peak area for vitamin Bi was 71 % of that for the internal standard. The analysis of a 0.125-g vitamin B complex tablet gave a peak area for vitamin Bi that was 1.82 times as great as that for the internal standard. How many milligrams of vitamin Bi are in the tablet ... 

Toxopyrimidine (pyramin lOlO) may be obtained from thiamine (vitamin Bi 1011) by acidic hydrolysis or by treatment with the thiaminase of Bacillus aneurinolyticus. Toxopyrimidine produces convulsions and death in rodents as do analogues, e.g. 2,4-dimethylpyrimidin-5-ylmethanol (1012) (65JMC750), but the effect is minimized or even... 

Liquid paraffin — triethanolamine vitamin Bi 2-fold chloroform — liquid paraffin —triethanolamine (60-1-10-1-10) [258]... 

Potassium hexacyanoferrate(III) forms, for example, fluorescent thiochrome with vitamin Bi ... 

Under long-wavelength UV light (2 = 365 nm) thiamine (/i/fr 40 — 45) appeared as a bluish fluorescent zone which could be employed for quantitative analysis (Fig. 1). The detection limit was 500 pg vitamin Bi per chromatogram zone. 

Finally, in connection with the investigations on the antineuritic action of homologs and analogs of vitamin Bi, the corresponding seleno compound was also mentioned. However, no details are given on the properties (except mp 203°C) and method of synthesis of this compound. 

Thiazoles play a prominent role in nature. For example, the thiazolium ring present in vitamin Bi serves as an electron sink and its coenzyme form is important for the decarboxylation of a-keto-acids. Furthermore, thiazoles are useful building blocks in pharmaceutical agents as exemplified by 2-(4-chlorophenyl)thiazole-4-acetic acid, a synthetic anti-inflammatory agent. 

See also Vitamin Bi Thiamine deficiency, 26 291 Thiamine hydrochloride, 25 795 Thiamine hydrochloride... 

This factor is particularly significant in OFBD since biological samples or isolates are used. In addition to background interference, fluorescence quenching has been demonstrated in a variety of biomolecules such as thiamine (vitamin Bi),(27) nicotinamide/28 nucleosides/nucleotides,(29) and pyruvate/30 To circumvent the obvious limitations associated with the use of UV or visible fluorophores in OFD, the potential... 

---