WHEAT FLOUR FORTIFICATION WITH IRON - Idpas.org

Analytical methods for monitoring wheat flour fortification with iron
2. It is a sensitive technique with a detection limit of 10 to 20 ppb and a linear range between 1
and 20 ppm of iron.
3. It is highly reliable, accurate, and precise.
4. Once the sample is ashed, the solution can be used for determining other elements.
5. Although the AAS instrument is expensive, it has a unique advantage, i.e. the ability for
simultaneous determinations of calcium, iron, copper, magnesium, zinc, and manganese.
6. It is ideal for analyzing a large number of samples.
Limitations
1. It requires skilled personnel who are trained to handle corrosive chemicals. Also, personnel
must be well trained in the use of the AAS instrument to optimize the instrument settings
and air-acetylene flow parameters.
2. The AAS method is a time-consuming procedure involving overnight dry ashing. Samples
with high protein content may take longer to be ashed.
3. The AAS instrument has high capital and maintenance costs. (See Appendix 3.1.)
Notes
1. Careful calibration of the AAS instrument with an iron standard solution is necessary. An
internal standard may also be needed to minimize matrix interference.
2. Both dry and wet ashing procedures are approved by AOAC for the preparation of plantbased
food samples for iron determination by AAS (AOAC 975.03, Appendix 3.9).
3. Wet ashing can also be performed using sulfuric and nitric acids. (See University of Chile
method, Appendix 3.10.)
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