Analysis of Inorganic Anions

There are numerous applications for the determination of mineral acids in the field of plating bath analyses. In copper sulfate plating baths based on electrodeposition, it is possible to simultaneously analyze the small amount of chloride contained in these baths along with the main component, sulfate (Fig. 9-93). 

An important constituent in copper pyrophosphate baths is nitrate, which enhances the maximum permissible current density [163]. The chromatogram in Fig. 9-94 shows the separation of nitrate and orthophosphate. The latter is the hydrolysis product of pyrophosphate and is formed during the plating process. If gradient elution with a hydroxide gradient is applied instead of an isocratic technique, the main component, pyrophosphate, may also be separated on a suitable anion exchanger and detected via suppressed conductivity. 

Nickel plating baths based on electroless deposition contain a reducing agent and a catalyst. The reducing agent acts as an electron donor for the reduction of metal ions to metal. Hypophosphite, formaldehyde, hydrazine, and boron hydride are suited for this. A colloidal Pd/Sn + solution usually serves as a catalyst This solution is adsorbed on the material surface and catalyzes the deposition of a monolayer of the corresponding metal. Further plating occurs autocataly-tically to form hydride ions. 

The following reaction scheme has been proposed for the electroless deposition of nickel with hypophosphite as reducing agent  

If the nickel bath also contains organic adds such as lactic add, it is necessary to apply a gradient technique, because lactic acid and hypophosphite have the same retention time under the isocratic conditions chosen in Fig. 9-95. 

The reference analytical methods for anions in wines and byproducts are summarized in Table 8.3. They use titrimetric, gravimetric approaches or selective ion electrodes, but today the most performed and extensively used approach for quality control analysis in oenology is ion chromatography. 

Fluoride (MA-F-AS321-03-FLUORU) The concentration of fluoride is measured using a fluoride selective ion electrode. The addition of a buffer provides a high constant ionic strength, complexes iron and aluminium and adjusts the pH to reduce HFHF2 formation. Matrix effects are minimized by using standard addition. Fluoride (2003.03) - the concentration of fluoride is measured with the use of a fluoride selective ion electrode. 

---

As pointed out above, IC is a well-established method for the analysis of inorganic anions and has become the method of choice in many application areas. Many techniques are available using singlecolumn [46] or dual-column systems with various detection modes. IC can be used both for analytical and preparative purposes. Large sample volumes, up to 1300 pul, can be injected to determine trace anions and cations and to attain detection limits of 10-400 ng/1. For determinations at a pig/1 to mg/1 level, a sample size of 10-50 xl is sufficient. Preconcentration is necessary for lower concentrations (an additional column, a sample pump, an extra valve and an extra time are the disadvantages of this approach [47]). With an IEC column and isocratic... 

INDIRECT UV DETECTION METHOD FOR ANALYSIS OF INORGANIC ANIONS... 

In connection with the introduction of a chromatographic system for the analysis of inorganic anions, in which the separator column was coupled directly to the conductivity cell, Fritz et al. [16,17] developed a series of macroporous, macroreticular anion exchangers of low capacity, featuring highly crosslinked PS/DVB particles as substrate (XAD-1, Rohm Haas, Philadelphia, PA, USA). The substrate was chloromethylated... 

When the chromatographic conditions for the analysis of inorganic anions are taken as a basis ), the lifetime of the exchanger cartridge is about 780 h. Even if, as suggested,... 

Fig. 8-21. Analysis of inorganic anions in the scrubber solution of a flue gas desulfurization plant. - Chromatographic conditions see Fig. 8-16 injection 50 pL sample (1 100 diluted).

Fig. 8-55. Analysis of inorganic anions in a detergent. - Separator column IonPac AS3 eluent 0.0028 mol/L NaHC03 + 0.0022 mol/L Na2C03 flow rate 2.3 mL/min detection suppressed conductivity injection 50 pL of a 0.1% detergent solution (1 5 diluted).

J. Moller and B. Winter, Application of Flow Injection Techniques for the Analysis of Inorganic Anions. Fresenius Z. Anal. Chem., 320 (1985) 451. 

Experiment 31. Determination of the amino acid composition of a peptide using pre-column derivatisation with o-phthalaldehyde and reverse phase HPLC and fluorescence detection Experiment 32. Analysis of inorganic anions in aqueous samples... 

Experiment 32. Analysis of inorganic anions in aqueous samples... 

Soga, T., and Imaizumi, M., Capillary electrophoresis method for the analysis of inorganic anions, organic acids, amino acids, nucleotides, carbohydrates and other anionic compounds. Electrophoresis, 22,3418,2001. 

In the analysis of inorganic anions using acetonitrile-water (3-1-7) containing citric acid and hexadecyltrimethylammonium hydroxide as eluent. Wheals reported that bromide, cyanide, dithionite, ferrocyanide, iodide, metabisulfite, nitrite, perborate, peroxide, sulfide, thiocyanate and thiosulfate respond at a GCE (-1-0.75 V vs Ag/AgCl). Dou and Krull have further shown that post-column irradiation (low pressure Hg arc discharge lamp) can facilitate the EC detection of chromate, dichromate and perchlorate and give improved sensitivity for thiocyanate. Despite this work, however, the application of EC detection to the analysis of these ions in biological systems has not been reported as yet. 

Carbonate/Bicarbonate-Selective Grafted Polymers The most common surface-functionalized, carbonate/bicarbonate-selective grafted polymer is available under the trade name Dionex lonPac AS14. This universal anion exchanger for the analysis of inorganic anions was developed as an advanced successor product of the nanobead-agglomerated lonPac AS12A [23] (see Section 3.4.1.4). 

Figure 10.95 Trace analysis of inorganic anions with capillary 1C through large-volume injection. Separator column Ion Pac AS19 column dimensions 250 mm x 0.4 mm i.d. column temperature 30 °C eluent 20mmol/L KOH (EG) flow rate lOpL/min detection ...

Figure 10.119 Analysis of inorganic anions in volume 50 (iL sample flue gas scrubber solu-a flue gas scrubber solution. Separator column Son, 1 100 diluted peaks 1 lOmg/L fluoride lonPac AS4 eluent 2.2 mmol/L Na2C03 + 25 (1), 650 mg/L chloride (2), 1300 mg/L nitrate...

---