Conclusions
Niacin, a water-soluble vitamin, is an essential nutrient which is also known as vitamin B3 or vitamin PP. It exists as nicotinic acid and nicotinamide which have equal biological activity and can also be synthesised from tryptophan. Niacin is directly or indirectly involved in many metabolic functions including the digestive system, skin, and nerves. It is also important for converting food to energy. A wide range of vitamin supplements containing nicotinamide are available and certain food types are often fortified with nicotinamide and other vitamins. Analysis is primarily required to confirm label declarations in fortified foods, feeds or supplements since unfortified foods contain little free niacin. A number of chemical, or microbiological assay techniques have been used for many years. HPLC methods using UV detection are available, although sensitivity and selectivity can be a problem. The use of mass spectrometric detection following HPLC has been used in more recent methods. Official methods are listed above. Microbiological assay has been the most commonly used assay technique for foods and has been used for the majority of available food nutrition datasets. However such techniques are expensive to support in the absence of a minimum level of use. A commercial test kit method is available that has been used successfully although care is required to select a suitable extraction protocol for different food types. Additional validation may be required. A method using aqueous extraction followed by ion-pair HPLC with UV detection is also available for analysis of vitamin premixes but is only suitable for this purpose. Deuterated niacin compounds are commercially available for MS procedures for the determination of niacin