TABLE 2.

Instrumental conditions of PerkinElmer Optima 4300DV ICP-OES.

	ICP source operation parameters
RF power	1300 W
Plasma gas flow	Ar 15 L min−1
Auxiliary gas flow	Ar 0.2 L min−1
Nebulizer gas flow	Ar 0.7 L min−1
Nebulizer	Borosilicate glass conical nebulizer
Spray chamber	Borosilicate glass cyclonic spray chamber
Sample uptake	1 ml min−1
	Spectrometer operating parameters
Viewing direction	Axial
Signal measurement mode	Peak area (3 point)
Background correction	Manually selected, 2 point interpolations
Measurement time	Auto
Measurement replications	Ten times
Measured emission line	La: 407.735 nm, Co: 238.892 nm