High-Purity Water Analysis

In addition to high-purity water analysis, ion chromatography is the primary method used for analyzing conditioned waters, which is a lot more difficult, because the concentrations of the chemicals used for conditioning exceed the analyte concentrations by many orders of magnitude. 

Heberling, S. (1996) Advances in high purity water analysis by ion chromatography. Presentation at the Symposium for Contamination Control in the Semiconductor and Electronics Industry, Sunnyvale, USA. 

Melanson, P. and M. Retzik. 1995. A second-generation TOC analysis system for high-purity water systems. Ultrapure Water 12(3) 76-79. 

Removal of cationic impurities from water. Careful analysis of water purified by various methods (see Table 7.10) indicates that the water that is obtained by passing ordinary distilled water through a small monobed deionizer (contained in polyethylene) and a submicrometer filter is equal or superior (with respect to cations) to water obtained by distillation in conventional quartz stills, and is distinctly superior to the product from systems constructed of metal.70 From the data available in the literature, simple distillation clearly does not produce high-purity water. In practice, two effects cause contamination of the distillate. Entrainment is the major factor that prevents the perfect separation of a volatile substance from nonvolatile solids during distillation. Rising bubbles of vapor break through the surface of the liquid with considerable force and throw a fog of droplets (of colloidal dimensions) into the vapor space... 

Lead (Note For this test, use reagent-grade chemicals with as low a lead content as is practicable as well as high-purity water and gases. Before use in this analysis, rinse all glassware and plasticware twice with 10% nitric acid and twice with 10% hydrochloric acid, and then rinse them thoroughly with... 

Fig. 8-19. Anion analysis of high purity water after pre-concentration. - Separator column IonPac AS4A chromatographic conditions see Fig. 8-13 concentrated volume 50 mL high purity water (SERAL).

Ding et al. described an automated on-line SPE-LC-MS/MS method for the determination of macrolide antibiotics, including erythromycin, roxithromycin, tylosin, and tilmicosin in environmental water samples. A Capcell Pak ME Ph-1 packed-column RAM was used as SPE column for the concentration of the analytes and clean-up of the sample. One millilitre of a water sample was injected into the conditioned SPE column, and the matrix was washed out with 3 ml high-purity water. By rotation of the switching valve (see Fig. 4.2), macrolides were eluted in the back-flush mode and transferred to the analytical column. The limits of detection and quantification obtained were 2-6 and 7-20 ng/1, respectively, which is suitable for trace analysis of macrolides. The intra- and inter-day precisions ranged within 2.9-12% and 3.3-8.9%, respectively. At the three fortification concentrations tested (20, 200, and 2000 ng/1), recoveries of macrolides ranged from 86.5% to 98.3%. 

The solutions of Cd in 1 M NaCl were prepared using Cd(N03)2 -4H20 (MERCK, pro analysi), NaCl (MERCK, pro analysi) and high-purity water which was obtained by passing distilled water through a Milli-Q water purification system. A supporting electrolyte of 1 M NaCl was used in all the experiments. 

Method and instrument blanks and, where possible, field blanks should be analyzed with each batch of samples. A method blank uses water, usually high-purity (double-distilled and deionized) water, which is processed through all laboratory steps in the same way as samples. An instrument blank uses the same water directly introduced into the detector. A field blank is high-purity water that has been bottled in the laboratory, shipped with sample bottles to the sampling site, processed, and preserved as a routine sample and returned with the routine samples to the laboratory for analysis. The analysis of a blank should not yield a value higher than that allowed by the acceptance criteria. Blanks are used to determine the limit of detection of a method and to monitor all aspects of the analytical process. 

While very low detection limits are definitely needed for analysis of high-purity water samples, this aspect of ion chromatography should not be overly emphasized. Determination of anions at the low ppm (mg L ) level is quite adequate for a great many samples. In fact, it is quite common to dilute a sample before injection in order to bring the analyte concentration into the desired range. This process is often called dilute and shoot Suppressed and nonsuppressed methods are equally valid for many sample types. 

Shortly after its introduction in 1975, ion chromatography was adopted by the power-generating industry to assay high-purity water for anionic and cationic impurities. Table 10.14 summarizes the IC detection methods for the analysis of mineral acids, orthosilicate, borate, alkali and alkaline-earth metals, and transition metals in high-purity water. While the analysis of orthosilicate and transition metals requires postcolumn derivatizations with subsequent photometric detection, all other analytes can be determined using suppressed conductivity detection. 

For trace analysis of borate in high-purity water a special concentrator column, TBC-1 (trace borate concentrator), was developed. The resin material contains cis-diol groups, on which borate is retained via complexation. When preconcentrating large volumes, detection limits of approximately 100 ng/L are achieved. A typical chromatogram of a 500 ng/L borate standard, obtained after pnevunatic preconcentration of 160 mL of the respective standard solution, was already shown in Figure 5.10 (see Section 5.5). An IonPac ICE-Borate coliunn, which is an IonPac ICE-ASl conditioned for borate analysis, was used as a separator. 

Figure 10.83 Trace analysis of orthosilicate in a high-purity water after preconcentration. Separator column lonPac AS4A-SC column dimensions 250 mm x2 mm i.d. eluent ...

Figure 10.84 Cation analysis of high-purity water sample after preconcentration. Separator column lonPac CS12A column dimensions 250 mm X 2 mm i.d. eluent lOmmol/L...

Water analysis Determination of mineral acids in high-purity water, process liquors, and rinsing and wastewater... 

Figure 10.131 Trace analysis of metals in a high-purity water sample. Separator column lonPac CS5A concentrator column lonPac CG2 eluent 6 mmol/L pyridine-2,6-dicarboxylic acid + 86 mmol/L LiOH flow...

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