Ion Chromatography is a part of the broader liquid chromatography technique. As the name suggests it deals with analysis of anions and cations. Practical ion chromatography was made possible by the innovative work of Dr. Hamish Small. In 1975 he reported a novel development of suppressor which simplified ion chromatography greatly and made it a useful tool for all laboratories.

The market for Ion Chromatography encompasses a wide range of industries and research. Globally the prominent market has been environment and food safety followed by others like pharmaceuticals, chem / petrochem, power, semiconductors etc. The Indian scenario is rather different as pharmaceutical industry leads in the area of Ion Chromatography.

It is estimated that 1C market is 10 per cent of the HPLC market globally but again the Indian situation is very different and has a significantly lesser ratio at 3-4 percent.

Instrumentation
Being a part of Liquid Chromatography 1C shares similar instrumentation like any LC but with some differences. The mobile phases used in ion chromatography can be extremely acidic or alkaline hence regular stainless steel systems are not suitable. The flow paths including the pump heads, autosampler injectors, columns and flow cells are made of polymeric material mostly PEEK.

Suppressor, the breakthrough component for 1C, essentially removes the cations from mobile phase and replaces it with a H+ ion in case of anion analysis. Similarly for cation analysis it removes anions and replaces it with OH-. This serves three purposes, one is to lower the background conductivity, remove analyte counter ion and increase sensitivity.

The earliest suppressors were packed bed which used a column body with a very high capacity ion exchange resin which had finite capacity and must be taken off-line and regenerated regularly. Suppressors evolved from packed bed to hollow fibre to micro membrane to the latest self regenerating suppressors (SRS) which are currently the standard.

The most common detector used in 1C is the conductivity detector but electrochemical detectors too have numerous applications followed by UV-Vis detector for analysis transition and heavy elements.

Application areas
The major market globally for Ion Chromatography has been in water testing for anions and cations be it drinking water, waste water, ground water, surface water, cooling tower water, boiler feed etc. In short water testing cutting across industries from environment to power to chem/petrochem forms the largest market for ion chromatographs. Analysis of common anions like chloride, fluoride, nitrate, nitrite, phosphate, sulphate and organic acids form the bulk of usage. Group I and II elements are easily separated and detected for cation analysis.

Food safety analysis is another major area for ion chromatography with applications in bottled water, carbonated and non carbonated beverages, fruit juices, functional drinks, nutritional supplements, fish, meat etc. The common analytes monitored are nitrate, nitrite, sulphite, preservatives and additives like benzoate, organic acids like tartrate, quinate, succinate, maleate, citrate etc along with biogenic amines which determine the indicators for food spoilage in this area, disinfection by products like bromate, oxyhalides etc.

Pharmaceutical testing is another market which has seen a sharp growth with the regulatory requirement to quantify ionic impurities. Increasingly one sees 1C methods in pharmacopoeia which is leading to higher sales in this area especially in India.

Apart from the inorganic testing Ion Chromatography is recognized as the gold standard for analysis of carbohydrates. Though these analysis are also performed by using other liquid chromatography techniques, 1C by far is more sensitivity and reliable for complex carbohydrates. It is now widely used in the pharmaceutical industry for determining the concentrations of sweetenerss or to monitor the sugars and alcohols in fermentation broths, glycoproteins and oligosaccharides in proteins based drugs, to determine polysaccharides in the manufacturing of vaccines etc. There are also methods available for determination of amino acids by direct injection and without derivatization.

Power and semiconductors are applications areas which are characterized by very low levels of detection limits in water and other process chemicals. Semiconductor market is almost non existing in India however the power sector holds a lot of promise, given huge investments planned in this decade.

Latest trends in Ion Chromatography
The last decade has seen a number of developments in Ion Chromatography which has mainly extended the ease of use of this technique and also increased the separation capabilities and sensitivity of detection.

Capillary 1C has been the latest path breaking technology introduced by Dionex which uses 0.2-0.6 mm columns, flow rates of 1 mL to 3 ml and sample volumes in the range of 0.4 mL. This has resulted in a 100 fold increase in mass sensitivity and also allows for direct injection on MS.

Development of Eluent Generator revolutionized the way Ion Chromatography is done.

The Indian market
In terms of units between 115-125 Ion Chromatographs are sold in India with a total volume of approximately US$ 7 million. The growth of Ion Chromatography is pegged at 20 per cent annually. Contrary to the global market distribution pharmaceutical market in India accounts for 40 per cent share followed by research, environment and food safety. The volumes for 1C are much lower in India as compared to other countries with similar GDP. The major markets globally are in food and environment which are only now seeing some serious legislations in India. One can expect the market to grow faster in coming years. The current per capita income of US$ 1200 seriously limits the market size as the national priorities are bound to be different. The growth will be directly linked to the growth of per capita income.

Conclusion
The Indian market for Ion Chromatographs though small holds promise of a faster growth as the Indian economy expands and we see increased investments in environment and food sector.