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The study of adverse effects of air pollution requires semi-continuous, rapid and accurate measurements of inorganic species in aerosols and their gas phase components in ambient air. The most promising instruments, often referred to as steam collecting devices, are the Particle-Into-Liquid-Sampler (PILS) coupled to wet-chemical analyzers such as a cation and/or anion chromatograph (IC) and the Monitoring instrument for AeRosols and GAses (MARGA) with two integrated ICs. Both instruments comprise gas denuders, a condensation particle growth sampler as well as pump and control devices. While PILS uses two consecutive fixed denuders and a downstream growth chamber, the MARGA system is composed of a Wet Rotating Denuder (WRD) and a Steam-Jet Aerosol Collector (SJAC). Although the aerosol samplers of PILS and MARGA use different assemblies, both apply the technique of growing aerosol particles into droplets in a supersaturated water vapor environment. Previously mixed with carrier water, the collected droplets are continuously fed into sample loops or preconcentration columns for on-line IC analysis. While PILS has been designed to sample aerosols only, MARGA additionally determines water-soluble gases. Compared to the classical denuders, which remove gases from the air sample upstream of the growth chamber, MARGA collects the gaseous species in a WRD for on-line analysis. In contrast to the gases, aerosols have low diffusion speeds and thus neither dissolve in the PILS denuders nor in the WRD. Proper selection of the ion chromatographic conditions of PILS-IC allows a precise determination, within 4 to 5 minutes, of seven major inorganic species (Na+, K+, Ca2+, Mg2+, Cl-, NO3- and SO4 2-) in fine aerosol particles. With longer analysis times (10-15 minutes) even airborne low-molecular-weight organic acids, such as acetate, formate and oxalate can be analyzed. MARGA additionally facilitates the simultaneous determination of HCl, HNO3, HNO2, SO2 and NH3.PILS and MARGA provide semi-continuous, long-term stand-alone measurements (1 week) and can measure particulate pollutants in the ng/m3 range.

This work was carried out with a Metrosep C 2 - 150 separation column, the following eluent parameters being investigated: nitric, tartaric, citric and oxalic acid concentration and concentration of the complexing anion of dipicolinic acid (DPA). The aim was to determine the effect of these parameters plus that of the column temperature on the retention times of alkali metals, alkaline earth metals, ammonium and amines using ion exchange chromatography with non-suppressed conductivity detection. Due to similar affinities for the ion exchange column, transition metals are difficult to separate with the classical nitric, tartaric, citric and oxalic acid eluents. Partial complexation with the dipicolinate ligand significantly shortens the retention times and improves the separation efficiency. However, too strong complexation results in a rapid passage through the column and thus in a complete loss of separation. Apart from a change in the elution order of magnesium and calcium at high DPA concentrations, other non-amine cations are only slightly affected by the eluent composition. Irrespective of the tartaric acid and nitric acid concentration in the eluent, an increase in column temperature shortens the retention times and slightly improves the peak symmetries of organic amine cations, particularly in the case of the trimethylamine cation. In contrast, an increase in column temperature in the presence of DPA concentrations exceeding 0.02 mmol/L increases the retention time of the transition metals. Depending on the separation problem, variation of the pH value, the use of a complexing agent and/or an increase in column temperature are powerful tools for broadening the scope of cation chromatography.

Comparative measurements show that the new Metrosep C 4 cation column has even better separation characteristics than the previous Metrosep C 2 and Metrosep Cation 1-2 column types. The Metrosep C 4 column has a clearly improved peak shape which leads to a better separation of the individual peaks. Using Metrosep C 4 the number of theoretical plates per meter was noticeably higher than that obtained on the Metrosep C 2 or C 1-2 column. Additionally for standard cations transition metals and amines, the Metrosep C 4 column shows better results with respect to peak shape, peak height, resolution and asymmetry factor. The clearly improved resolution of the C 4 column with its narrow and high peaks achieves baseline separation for six standard and six transition metal cations. Analysis times and peak areas obtained with the C 4 column are in the same range as those obtained with its predecessors.As a result of the latest production methods and materials, the promising Metrosep C 4 column excels by an outstanding separation performance for complex mixtures comprising standard cations, transition metal cations and amines.

The combination of 850 Professional IC, 858 Professional Sample Processor, Dosino and MagIC NetTM software offers a variety of automated ion chromatographic sample preparation and calibration techniques available as an anion, cation or dual channel system. Calibration is straightforward and requires only one multi-ion standard.Inline calibration allows the calibration of any standard concentration in the ppt range by using one single stable standard solution at the ppb level. By using a preconcentration column and switching the valves one, two or more times different calibration concentrations at the ultra-trace level can be created with unprecedented reproducibility. The inline preconcentration technique uses a pre-concentration column and is ideally suited for trace analysis in complex matrices, especially when combined with matrix elimination. Besides facilitating the preparation of g/L to ng/L calibration graphs Metrohm`s intelligent techniques are capable of logical decision making. While Metrohm`s intelligent Partial Loop technique (MiPT) allows samples with a wide concentration range to be injected without previous manual dilution, the intelligent inline dilution technique, after the first sample injection, compares peak areas, calculates, if necessary, the dilution factor, dilutes and automatically re-injects the sample. The presented inline techniques allow the rationalization of the time-consuming, error-prone and cost-intensive manual preparation of standard solutions. They guarantee that the determined sample concentrations always lie within the calibration range. Higher sample throughputs as well as lower analysis costs and improved data reliability are achieved.

In routine chemical analysis, the predominant challenge involves a higher sample throughput, improved reproducibility, liquid handling flexibility and reduced personnel costs. In response to these requirements, the 872 Extension Module Liquid Handling in combination with the MagIC NetTM software and the well-proven Dosino technology expands the possibilities of inline sample preparation and opens up new fields of application. Among others, the module can be used, together with an optional mixing vessel, for pH adjustments, pre-column derivatizations, or the mixing of solutions.As a representative of an inline sample preparation technique, this poster describes the performance of precise dilutions. By using only one single stable standard solution, multi-point calibration curves can be automatically recorded by diluting a concentrated standard in an external vessel.

The presented IC system with inline sample preparation allows the determination of traces of lithium and sodium (ppt) in the presence of ppm quantities of ammonium and ethanolamine.

This poster presents an approach that couples a Particle-Into-Liquid-Sampler (PILS) to a dual-channel ion chromatograph (IC) for measurement of aerosol anions and cations and a voltammetric measuring stand (VA) to determine the heavy metals. Feasibility of the PILS-IC-VA online system was demonstrated by collecting aerosol samples in Herisau Switzerland, at defined time intervals; air pollution events were simulated by burning lead- and cadmium-coated sparklers.

The potentiometric titration of Kjeldahl nitrogen is one of the most common analytic procedures. It is referenced in numerous standards, ranging from the food and animal feed industries through sewage and waste analysis and all the way to the fertilizer industry. As a rule, the samples are digested with concentrated sulfuric acid with the addition of a catalyst. The ammonium sulfate that is formed is distilled as ammonia in alkali solution, collected in an absorption solution and titrated there.This Bulletin provides a detailed description of potentiometric nitrogen determination following distillation of the digestion solution, followed by a discussion of the possibilities of coulometric titration (without distillation).

Methods are described for the potentiometric analysis of the following bath components:Brass plating bath: copper, zinc, free cyanide, ammonium, carbonate, and sulfite.Bronze plating bath: copper, tin, and free cyanide.

The potassium (or ammonium) ion is precipitated with sodium tetraphenyl borate, and the excess of this reagent back-titrated against the thallous(I) ion, using biamperometric endpoint detection. Ammonium can either be titrated together in an acid solution, or driven off by previous boiling in an alkaline solution. Methods are given for determining potassium in the presence of large excesses of sodium, ammonium, calcium, and magnesium.

Although the known photometric methods for the determination of ammonia/ammonium are accurate, they require a considerable amount of time (Nessler method 30 min, indophenol method 90 min reaction time). A further disadvantage of these methods is that only clear solutions can be measured. Opaque solutions must first be clarified by time-consuming procedures. These problems do not exist with the ion-selective ammonia electrode. Measurements can be easily performed in waste water, liquid fertilizer, and urine as well as in soil extracts. Especially for fresh water and waste water samples several standards, such as ISO 6778, EPA 350.2, EPA 305.3 and ASTM D1426, describe the analysis of ammonium by ion measurement. In this Application Bulletin, the determination according to these standards is described besides the determination of other samples as well as some general tips and tricks on how to handle the ammonia ion selective electrode. Determination of ammonia in ammonium salts, of the nitric acid content in nitrates, and of the nitrogen content of organic compounds with the ion-selective ammonia electrode is based on the principle that the ammonium ion is released as ammonia gas upon addition of excess caustic soda:NH4+ + OH- = NH3 + H2OThe outer membrane of the electrode allows the ammonia to diffuse through. The change in the pH value of the inner electrolyte solution is monitored by a combined glass electrode. If the substance to be measured is not present in the form of an ammonium salt, it must first be converted into one. Organic nitrogen compounds, especially amino compounds are digested according to Kjeldahl by heating with concentrated sulfuric acid. The carbon is oxidized to carbon dioxide in the process while the organic nitrogen is transformed quantitatively into ammonium sulfate.

This Bulletin gives a survey of standard methods from the field of water analysis. You will also find the analytical instruments required for the respective determinations and references to the corresponding Metrohm Application Bulletins and Application Notes. The following parameters are dealt with: electrical conductivity, pH value, fluoride, ammonium and Kjeldahl nitrogen, anions and cations by means of ion chromatography, heavy metals by means of voltammetry, chemical oxygen demand (COD), water hardness, free chlorine as well as a few other water constituents.

The two potentiometric titration methods described here allow the determination of the content of commercial betaine solutions. Neither method is suitable for determining the betaine content of formulations. The possibilities and limits of both methods are described and distinctive features and possible sources of interference are mentioned. The Bulletin explains the most important theoretical principles and is intended to help users to develop their own product-specific titration methods.

Determination of sodium, ammonium, potassium, calcium, and magnesium in 4% boric acid using cation chromatography with direct conductivity detection.

Determination of zinc, lithium, cobalt, sodium, ammonium, potassium, manganese, magnesium, and calcium in power plant feed water stabilized with 7 ppm monoethanolamine using cation chromatography with direct conductivity detection.

Determination of lead, zinc, indium, cadmium, cobalt, ammonium, potassium, manganese, magnesium, and calcium using cation chromatography with direct conductivity detection.

Determination of sodium, ammonium, methylamine, guanidine (Gu), and aminoguanidine (Agu) in wastewater using cation chromatography with direct conductivity detection.

Determination of sodium, ammonium, and potassium in polyethers using cation chromatography with direct conductivity detection.

Determination of sodium, ammonium, potassium, calcium, and magnesium in betaine using cation chromatography with direct conductivity detection.

Determination of sodium, ammonium, potassium, calcium, and magnesium in a grapefruit soft drink using cation chromatography with direct conductivity detection after advanced dialysis for inline sample preparation.

Determination of sodium, ammonium, potassium, calcium, and magnesium in a functional fruit juice using cation chromatography with direct conductivity detection after advanced dialysis for inline sample preparation.

Determination of sodium, potassium, DMEA (dimethylethanolamine), calcium, choline, and magnesium in a saline solution using cation chromatography with direct conductivity detection.

Determination of ammonium, magnesium, and calcium in a fertilizer using cation chromatography with directconductivity detection.

Determination of trace levels of lithium, sodium, ammonium, potassium, magnesium, and calcium in boiler feed water using cation chromatography with direct conductivity detection.

Determination of ammonium, potassium, magnesium, and calcium in a liquid fertilizer using cation chromatography with direct conductivity detection..

Determination of betaine in the presence of standard cations in an Echinacea product using cation chromatography with direct conductivity detection.

Determination of traces of lithium, sodium, ammonium, potassium, calcium, and magnesium in ethanol using cation chromatography with direct conductivity detection after Metrohm Inline Matrix Elimination.

Determination of choline in infant milk powder using cation chromatography with direct conductivity detection applying Metrohm Inline Dialysis.

Determination of traces of ammonium in the presence of sodium, potassium, magnesium, and calcium using cation chromatography with direct conductivity detection.

Long-term determination of standard cations with automatic inline eluent preparation using Dosino and Level Control instruments and cation chromatography with direct conductivity detection.

Determination of lysine as well as sodium, ammonium, potassium, and calcium in bulk lysine using cation chromatography with direct conductivity detection.

Determination of sodium, ammonium, potassium, magnesium, and calcium in an ambient aerosol (PM2.5) using aerosol sampling with the PILS (Particle Into Liquid Sampler) and cation chromatography with direct conductivity detection.

Calibration of lithium, sodium, ammonium, zinc, potassium, magnesium, and calcium using the partial loop technique and cation chromatography with direct conductivity detection. This technique allows a calibration range of 1:100 (e.g. 1 μg/L to 100 μg/L corresponding to 2 μL to 200 μL injected volume) out of 1 calibration solution. Applying the full range of partial loop injection to the samples one calibration covers a sample concentration range of 1 to 10'000 e.g. 2 μL of a 10 mg/L solution corresponds to the highest calibration level (100 μg/L) while 200 μL of a 1 μg/L solution corresponds to the lowest calibration level.

Determination of lithium, sodium, ammonium, zinc, potassium, magnesium, and calcium impurities in syringe filters using cation chromatography with direct conductivity detection.

Determination of Bethanechol Chloride and HPTA (2-hydroxy-propyl-trimethyl ammonium chloride) besides sodium and calcium using cation chromatography with direct conductivity detection.

Determination of lithium, sodium, ammonium, potassium, calcium, magnesium, and strontium in brine using cation chromatography with direct conductivity detection.

Determination of lithium, sodium, ammonium, potassium, manganese, calcium, magnesium, strontium, and barium using cation chromatography with direct conductivity detection.

Determination of lithium, sodium, ammonium, potassium, manganese, calcium, magnesium, strontium, and barium in an offshore effluent using cation chromatography with direct conductivity detection.

Determination of lithium, sodium, ammonium, and monoethanolamine (MEA) using cation chromatography with direct conductivity detection and Metrohm Inline Preconcentration and Inline Calibration.

Eluent preparation on demand (EPOD) is the convenient and flexible way of automatic eluent preparation. The 849 Level Control together with an 800 Dosino equipped with a 50 mL dosing unit are used to dilute an eluent concentrate to the required eluent concentration. The use of eluent concentrates is suitable for any eluent. This facilitates unattended operation of the system over several weeks (see AN S-296 for anion eluent preparation).

Drinking water analysis is strongly regulated by standards. In this Application Note, the cation determination according to ISO 14911 is shown. The Metrosep C 4 - 150/4.0 is the optimum separation column for this purpose.

Water chemistry of the water-steam cycle is crucial for maintaining plant reliability and for ensuring optimal plant operational conditions. Impurities such as corrosion products in ionic, colloidal, or oxide forms are ubiquitous in feedwater, condensate, and reactor coolant. This application shows the determination of sub-ppb levels of Cu, Ni, Zn and standard cations (e.g., Na+, NH4+, Mg2+, Ca2+) in the water-steam cycle of a BWR.

Water in steel-based cooling systems requires a pH value slightly above 7 to prevent corrosion. Often ammonium or organic amines are applied for pH adjustement. This application shows the separation of typical amines besides inorganic cations. Sample preconcentration applies combined Inline Preconcentration and Matrix Elimination (MiPCT-ME).

The Metrosep C 6 columns have a higher capacity than those of the Metrosep C 4. The present Application Note describes the exceptional separating efficiency for standard cations with the three Metrosep C 6 column lengths available. The outstanding sodium-ammonia separation is particularly noteworthy.

Maritime pore water contains sodium in the percentage range. The analysis of ammonia in this kind of sample requires a high column capacity and an exceptionally good separation of sodium and ammonia. These requirements are completely fulfilled by a 2 µL injection to the high-capacity Metrosep C 6 - 250/4.0 column.

The determination of low ammonium concentrations besides excess sodium is demanding due to the small retention time difference of these two cations. This Application Note shows direct conductivity detection as an ideal means to detect ammonium in a wastewater sample containing 400 mg/L sodium. AN-S-313 shows the analysis of nitrite traces.

Bethanechol is a pharmaceutical compound which is used to treat urinary retention. This API (active pharmaceutical ingredient) can be determined by cation chromatography with direct conductivity detection. A good separation is achieved between bethanechol and its degradation product 2-hydroxy-propyl-trimethyl ammonium (HPTA) and the standard cations. Peak shape and resolution meet the USP requirements for bethanechol.

Sample dilution is a work-intensive routine task in the analysis laboratory. An automatic two-step dilution exponentiates the dilution factor – 1:100 – thus incorporating a dilution factor of 10,000. The intelligent dilution is made possible by MagIC Net, which calculates the essential dilution steps, and by the dosing properties of the 800 Dosino and the Liquid Handling Station. The Application Note shows statistical results of a 1:10,000 dilution.

Cleanliness is indispensable in electronics production. Ionic contaminations in particular lead to a drastic worsening of the quality of the printed circuit boards. The present Application Note describes the determination of cations on printed circuit board surfaces. The intelligent Partial Loop Injection Technique (MiPT) used for this purpose permits the determination of cations and anions in the same sample. The determination of the anions is described in AN-S-317.

Fast IC means short run times on separation columns with a relatively high flow rate and the standard eluent. Here the standard cations are separated within eleven minutes on the Metrosep C 4 - 250/2.0. The sodium and ammonium peaks are separated from one another under these conditions.