Simultaneous determination of silicate and phosphate in environmental waters using pre-column derivatization ion-pair liquid chromatography.

A highly sensitive HPLC method for the simultaneous determination of soluble silicate and phosphate in environmental waters was developed, using ion-pair liquid chromatography preceded by the formation of their yellow alpha-heteropolymolybdates. The moderate-pH mobile phase enabled to use a highly efficient reversed-phase silica column. The pre-column coloring reactions at moderate-pH were reproducible for both silicate and phosphate in all quantification ranges with R.S.D.s less than 2% and 5%, respectively. The linear calibration lines between concentrations (mg-SiO(2)/L and mg-PO(4)/L) and peak area intensities were obtained for silicate and phosphate both with acceptable determination coefficients (r(2)) of 0.9999. The limits of determination for both analytes were 0.007 mg-SiO(2)/L and 0.003 mg-PO(4)/L, which were calculated theoretically using 10sigma/slope. The four-digit dynamic ranges were obtained for 0.007-10mg-SiO(2)/L and 0.003-20mg-PO(4)/L. The developed method was applied for the analysis of tap water, river water, coastal seawater, well water, hot-spring water, commercial mineral water, and laboratory water. The results were very reasonable and acceptable from the environmental viewpoints, which were well correlated with those confirmed by the molybdenum-blue spectrophotometry.

[1]  A. Y. El-Sayed,et al.  Simultaneous determination of phosphate and silicate in detergents and waters by first-derivative spectrophotometry , 2001 .

[2]  D. F. Boltz,et al.  Spectrophotometric Study of Modified Heteropoly Blue Method for Phosphorus , 1956 .

[3]  A. G. Fogg,et al.  Differential-pulse voltammetric determination of phosphate as molybdovanadophosphate at a glassy carbon electrode and assessment of eluents for the flow injection voltammetric determination of phosphate, silicate, arsenate and germanate , 1981 .

[4]  P. Worsfold,et al.  High temporal resolution field monitoring of phosphate in the River Frome using flow injection with diode array detection , 2001 .

[5]  F. Sigon,et al.  Flow-injection analysis for power plants: Evaluation of detectors for the determination of control parameters in conditioned water—steam cycles , 1990 .

[6]  P. Worsfold,et al.  Determination of Dissolved Reactive Phosphorus in Estuarine Waters Using a Reversed Flow Injection Manifold , 1997 .

[7]  G. Piccardi,et al.  Spectrophotometric determination of silicate in rain and aerosols by flow analysis , 1999 .

[8]  J. Paul.  Simulataneous determination of silicon and phosphorus in the presence of each other , 1960 .

[9]  K. Johnson,et al.  Determination of phosphate in seawater by flow injection analysis with injection of reagent , 1982 .

[10]  A. G. Sinclair,et al.  Analytical applications of β-heteropoly acids , 1965 .

[11]  H. B. Li,et al.  Determination of silicate in water by ion exclusion chromatography with conductivity detection. , 2000, Journal of chromatography. A.

[12]  A. J. Walker,et al.  The spectrophotometric determination of silicic acid in dilute solution , 1964 .

[13]  I. McKelvie,et al.  Separation and detection of condensed phosphates in waste waters by ion chromatography coupled with flow injection , 1996 .

[14]  A. G. Sinclair,et al.  Analytical applications of β-heteropoly acids : Part I. Determination of arsenic, germanium and silicon , 1965 .

[15]  J. Strickland.  The Preparation and Properties of Silicomolybdic Acid. II. The Preparation and Properties of β-Silicomolybdic Acid , 1952 .

[16]  T. Yokoyama,et al.  Spectrophotometric Determination of Silicic Acid by Flow Injection Analysis , 1982 .

[17]  Kikuo Kato,et al.  Spectrophotometric determination of dissolved silica based on α-molybdosilicic acid formation , 1976 .

[18]  M. C. Schwartz.  Photometric Determination of Silica in Presence of Phosphates , 1942 .

[19]  C. V. Banks,et al.  SPECTROPHOTOMETRIC DETERMINATION OF SILICON IN THE PRESENCE OF ZIRCONIUM, BERYLLIUM, ALUMINUM AND CALCIUM , 1951 .

[20]  Christopher J. Smith,et al.  The formation of molybdosilicic acids from mixed solutions of molybdate and silicate , 1975 .

[21]  Y. Narusawa.  Flow-injection spectrophotometric determination of silicate, phosphate and arsenate with on-line column separation , 1988 .

[22]  R. Cattrall,et al.  Time-division multiplex technique for producing concentration profiles in flow analysis , 1998 .

[23]  D. F. Boltz,et al.  Determination of Phosphorus, Germanium, Silicon, and Arsenic , 1947 .

[24]  J. Strickland.  The Preparation and Properties of Silicomolybdic Acid. III. The Combination of Silicate and Molybdate , 1952 .

[25]  G. Christian,et al.  Enhancement of flow injection optosensing by sorbent extraction and reaction rate measurement , 1990 .

[26]  Wenzhi Hu,et al.  Selective and Simultaneous Determination of Phosphate and Silicate Ions in Leaching Process Waters for Ceramics Glaze Raw Materials of Narutal Origin by Ion-Exclusion Chromatography Coupled with UV-detection after Postcolumn Derivatization , 2006, Analytical sciences : the international journal of the Japan Society for Analytical Chemistry.

[27]  K. Johnson,et al.  Determination of reactive silicate in seawater by flow injection analysis , 1983 .

[28]  J. Burguera,et al.  A flow injection-ETAAS system for the on-line determination of total and dissolved silica in waters. , 2002, Talanta.

[29]  L. Rogers,et al.  SPECTROPHOTOMETRIC AND POLAROGRAPHIC DETERMINATIONS OF SOLUBLE SILICATE , 1954 .

[30]  J. Ruzicka,et al.  Flow injection analyses , 1975 .

[31]  J. P. Riley,et al.  A modified single solution method for the determination of phosphate in natural waters , 1962 .

[32]  Paul J Worsfold,et al.  A compact flow injection analysis system for surface mapping of phosphate in marine waters. , 2002, Talanta.

[33]  O. Borggaard,et al.  Determination of silicon in soil extracts by flow injection analysis , 1985 .

[34]  L. Rogers,et al.  Spectrophotometric Determination of Arsenic, Phosphorus, and Silicon in Presence of Each Other , 1954 .

[35]  J. Strickland.  The Preparation and Properties of Silicomolybdic Acid. I. The Properties of Alpha Silicomolybdic Acid , 1952 .

[36]  N. Nakagoshi,et al.  Simultaneous spectrophotometric determination of phosphate and silicate ions in river water by using ion-exclusion chromatographic separation and post-column derivatization. , 2008, Analytica chimica acta.

[37]  M. Mellon,et al.  Extraction of Heteropoly Acids , 1953 .

[38]  R. Robinson,et al.  Forms of Silicate Available for Colorimetric Determination , 1953 .

[39]  J. P. Riley,et al.  The colorimetric determination of silicate with special reference to sea and natural waters , 1955 .

[40]  B. Birch,et al.  Static and flow injection voltammetric determinations of total phosphate and soluble silicate in commercial washing powders at a glassy carbon electrode , 1983 .

[41]  H. Kimura,et al.  Spectrophotometric determination of silicon in silicates by flow-injection analysis. , 1985, Talanta.

[42]  A. El-Sayed,et al.  Simultaneous Determination of Phosphate and Silicate by First-Derivative Spectrophotometry , 2001, Analytical sciences : the international journal of the Japan Society for Analytical Chemistry.