Reference

The coulometric generation of tungstate ion from a tungsten electrode in aqueous base solutions

The coulometric generation of tungstate ion from a tungsten electrode in aqueous base solutions. Kelsey, G. Stephen (Dep. Chem., Univ. Missouri, Columbia, Mo., USA). Anal. Chim. Acta, 93, 287-90 (English) 1977. CODEN: ACACAM. DOCUMENT TYPE: Journal CA Section: 72 (Electrochemistry) Section cross-reference(s): 78, 79 The conditions of c.d., basicity, and temp. conductive to quant. generation of W(VI) were detd. as a continuation of the anodic oxidn. study of Group VI metals in aq. soln., and in particular of the electrode kinetics of W in aq. basic solns. The prodn. of WO42- [14311-52-5] from anodic oxidn. of the parent metal proceeds with 100% current efficiency over a wide range of c.d. values and temps. in basic solns. Although the passivity prohibits applications requiring in situ generation in acidic media, the method lends itself to coulometric titrns. with externally generated WO42-. It also suggests a method for prepg. std. tungstate solns. of low concn., where gravimetric methods would not suffice.

Spectrophotometric determination of tungstate using an iron salt, a thiol, and oxygen

Spectrophotometric determination of tungstate using an iron salt, a thiol, and oxygen. Eberhard, Anatol; Kenyon, George L. (Dep. Chem., Ithaca Coll., Ithaca, NY 14850, USA). Analyst (London), 112(3), 305-7 (English) 1987. CODEN: ANALAO. ISSN: 0003-2654. DOCUMENT TYPE: Journal CA Section: 79 (Inorganic Analytical Chemistry) A simple, fast, and inexpensive method for the detn. of W as tungstate was developed. The detn. uses only reagents that are commonly found in biochem. labs., i.e., iron(II) ammonium sulfate or FeCl3, a thiol such as cysteine, 2-aminoethanethiol, or 2-thioethanol, O gas and a buffer (phthalate, acetate, or glutarate) at pH 5.8. A compd. of unknown structure is formed, which has an absorbance max. at 475 nm (for cysteine) with molar absorptivity of 420 L mol-1 cm-1, allowing the detn. 14311-52-5 and 616-91-1 are just another two chemicals used in this study. of 0.5-10 mmol tungstate/mL. .