Ion Chromatograph - IC

Analyses were done on a Dionex Model 14 Ion Chromatograph (IC), equipped with a Waters WISP 7 autosampler, Linear recorder, and interfaced with a Hewlett-Packard 3354 Laboratory Automated System. The principal components of the IC, shown in Figure 2, are (A) eluent reservoir, (B) pump, (C) injection valve, (D) separator column, (E) suppressor column, (F) conductivity cell, and (G) conductance meter with a recorder (integrator). 

Avicel RC and CL are water-dispersible, colloidal, microcrystalline cellulose products made for use in liquid preparations. Avicel RC and CL are coprocessed mixtures of microcrystalline cellulose and sodium carboxymethylcellulose. The amount of NaCMC can be determined using the IC method. About 10 g of Nasonex and about 25 mg of NaCMC NF are separately refluxed with 30 mL of glacial acetic acid for 2 h. The refluxed mixture is transferred to a 100-mL volumetric flask and diluted to volume with purified water, and mixed. The ion chromatograph (IC) was equipped with a suppressed conductivity detector, a 4-mm CSRS suppressor, current at 50 mA, a 250 mm x 4-mm Ion CS 12A column and a 50 mm x 4 mm Ion CG 12A guard column. The mobile phase is 0.13% methanesulfonic acid in water with a flow rate of 1 mL/min. Equal... 

While this spectroscopic technique may accurately and reliably analyze the salt forms, it lacks adequate precision to meet the release specifications. A method developed from this technique would not therefore meet the regulatory requirement and could not be validated for this application. Consequently, an ion chromatographic (IC) method should be developed to separate and quantitate both potassium and sodium, which theoretically can meet the precision requirement of 2.0 %. This chromatographic technique would meet the regulatory requirement and could be successfully validated. 

IC/HPLC The concentrations of selected major anions for 24 h leachate are determined by ion chromatography (Dionex Series 4000i Ion Chromatograph [IC] equipped with a conductivity detector). The concentrations of selected organics in 24 h leachate are determined by high-pressure Uquid chromatography (HPLC). 

The principles underlying IC can be found in any number of introductory texts discussed in the references on IC found in Chapter 4. Suppliers of ion chromatographs, IC columns, and related accessories such as Dionex Corporation and Alltech Associates are good sources of technical notes and applications. 

An Ion Chromatograph has been successfully automated by interfacing it to an automatic sampler (7). Continuous unattended analysis was possible, the actual number of samples analyzed being limited by the ionic capacity of the suppressor column. The automated Ion Chromatograph was used to analyze soluble sulfates, ammonia and alkyl amines in stack and automobile exhqust samples. Excellent agreement between IC and automated barium chloroanilate titration for sulfate was obtained with a relative standard deviation less than 5%. 

IC can also be used in detection of some acids. Zhao et al. [25] proposed a simple and eco-friendly ion chromatographic method for the determination of Hippuric acid (HA) in human urine (see Figure 12). Hippuric acid is a kind of metabolite of toluene in human body, therefore, HA is a physiological component of human urine if toluene was inhaled. The content of HA in human urine actually is confirmed as a diagnostic marker of exposure to toluene [26]. It has been reported that exposure to high concentrations of volatile organic compounds such as... 

Simplified analytical procedures for determination of gas-phase organic acids would be very beneficial. Currently, the acids are collected by using impregnated filters, denuder tubes, or water absorption techniques and then an ion chromatographic analysis. Normally, the collection and analysis steps are decoupled in time (i.e, samples collected at a field site are returned to a home laboratory for IC analysis). Once again, blank samples must be utilized to compensate for contamination during transport and storage prior to analysis. 

A CE determination of fluoride in rain water was compared with IC and ISE potentiometry the IC response was related to the total concentration, whereas CE and ISE responded to free fluoride [50]. The fluoride concentrations obtained by CE and ISE were systematically lower than those obtained by IC due to the fluoride complexation with aluminium. The detection limits for IC and ISE were similar (0.2 and 0.3 pmol/l) and somewhat lower than those for CE (0.6 xmol/l). CE was evaluated as an alternative method to the EPA ion chromatographic method for the determination of anions in water and a better resolution and a shorter analysis time were found for CE [51]. 

The 2.2.2 column is especially advantageous in the determination of fluoride ion, which in traditional IC often elutes so early as to be masked by the injection peak. [32] In similar fashion, Tsai and Shih [33] derivatized polystyrene/divinylbenzene resin with cryptand 2.2.2 for the ion chromatographic separation of cations or anions. 

Using a macrocycle as a mobile phase additive is only practical for simple, inexpensive, relatively low-toxicity macrocycles such as 18-crown-6. A recent example of the benefits to be derived from addition of 18-crown-6 to an ion chromatographic eluent is found in work published by Lamb s group. [72] Specifically, in separating alkali, alkaline earth and amine cations by IC, it was found that addition of the macrocycle to the mobile phase could be used to adjust the retention time of ammonium cation so that ammonium ion could be determined under concentration ratios of 60,000 1 Na+ to NH4+ (see Figure 7). This method has specific application in the determination of ammonia produced by nitrogenase—analysis time and sample size are considerably reduced over traditional wet chemical methods. 

Metals contained in samples are determined by a wide variety of analytical methods. Bulk metals, such as copper in brass or iron in steel, can be analyzed readily by chemical methods such as gravimetry or electrochemistry. However, many metal determinations are for smaller, or trace, quantities. These are determined by various spectroscopic or chromatographic methods, such as atomic absorbance spectrometry using flame (FAAS) or graphite furnace (GFAAS) atomization, atomic emission spectrometry (AES), inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), x-ray fluorescence (XRF), and ion chromatography (IC). 

Other Detectors. The conductivity detector is increasing in popularity because it is usually the detector used in ion chromatographs. The special problems associated with its use were discussed in the section on IC. 

In this study, a Model IC 100 ion chromatograph made by Yokogawa Co. was used for determination of S(IV) in the solution. 

The known compounds in PSG films can be quantitatively measured colorimetrically. The ion chromatographic data based on the measurement of phosphate and phosphite ion do not give accurate results for total weight percent of phosphorus. The difference between the IC results and colorimetric results is believed to be due to unidentified or missing peaks in the IC that contain phosphorus. Until these compounds are identified, the most reliable method for measuring the known phosphorus compounds and total weight percent phosphorus appears to be colorimetry. 

In aqueous chemistry, tellurium is mainly found as telluride (Te- ), tellurite (Te03 ), and tellurate (Te04 ). Zolotov et al. [19] developed an IC procedure for the separation of TeOi, and Te04 by a suppressed ion-chromatographic system. In the method, F interfered with the determination of TeO., while S04 " interfered with the determination of Te04. In a report by Chen et al. [20], a similar method was used to speciate tellurium. The detection limits for Te04 were very poor in both methods. The studies were confined only to standard solutions. 

Nitrate. In this case, the method of choice would be IC, with conductivity detection. The use of a dedicated ion chromatograph with an anion-exchange column allows the separation of nitrate (plus fluoride, chloride, bromide, nitrite, sulfate, etc.). 

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