title: Spectrophotometric determination of silicate traces in hemodialysis solutions.
abstract: Reliable methods for the analysis of silicon are of great importance, because it seems that the silicate anion can reduce aluminum bioavailability in patients undergoing dialysis. Thus, a simple and sensitive spectrophotometric method is described for the determination of silicate traces in dialysis solutions. The method is based on the reaction between silicate ions and excess ammonium molybdate reagent to give a yellow silico-molybdic complex. This complex is then reduced to the heteropoly blue compound by means of ascorbic acid. Absorbance values are measured at 830 nm, and are stable for more than 2 h. A good linearity was obtained up to 300 ng ml(-1) of silicon concentration. The accuracy and the precision of the method were good; relative standard deviation values of 2% intraday and of 3.9% interday for six replicates on 40 ng ml(-1) standard silicate solutions were found. Results of the analysis of some commercial hemodialysis solution samples, obtained by means of the 'standard additions' method, are provided.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, University of Bologna, Italy. raggima@kaiser.alma.unibo.it
authors.forename: M A
authors.initials: MA
authors.lastname: Raggi
authors.forename: C
authors.initials: C
authors.lastname: Sabbioni
authors.forename: R
authors.initials: R
authors.lastname: Mandrioli
authors.forename: Q
authors.initials: Q
authors.lastname: Zini
authors.forename: G
authors.initials: G
authors.lastname: Varani
mesh_terms: D000535:Aluminum / Q000032:analysis; D002138:Calibration; D015312:Hemodialysis Solutions / Q000032:analysis*; D006801:Humans; D007202:Indicators and Reagents; D008982:Molybdenum; D010472:Perchlorates / Q000032:analysis; D015203:Reproducibility of Results; D017640:Silicates / Q000032:analysis*; D012824:Silicic Acid; D012996:Solutions; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D015312:Hemodialysis Solutions; D007202:Indicators and Reagents; D010472:Perchlorates; D017640:Silicates; D012996:Solutions; D012824:Silicic Acid; D008982:Molybdenum; D000535:Aluminum; C022175:ammonium molybdate