Trace Level Arsenic Quantification through Cloud Point Extraction: Application to Biological and Environmental Samples

Table 1

Effect of foreign ions.

Interferent	Tolerance limit (μg)
Ca^2+, Cl^−, Zn^2+, Ni^2+, Co^2+, F^−	>2000
Cd^2+,SO42−, I^−, NO3−	>1000
Na^+, K^+, Mg^2+, Fe^3+, Fe^2+	800
Pb^2+, Ba^2+, Cu^2+, Al^3+,Hg^2+	500
PO43−	900^a
	10
	50^b
SiO32−	40
	100^c

^aThe white precipitate formed by the addition of the above metal ions was removed by centrifuging the solution, and then the reducing agent was added followed by the surfactant for preconcentrating the formed blue complex.
^bThe calcium nitrate was added before adding the molybdate so that phosphate does not form blue complex.
^cThe tartaric acid was used to mask the silica interference, otherwise it forms silicomolybdenum blue and causes positive interference.