Determination of Lead in Mexican Candy and Flavored Salt Products
GFAAS Analysis
The GFAAS analysis procedure is likewise detailed in EAM 4.3 [10]. These analyses were
performed using a Varian model SpectrAA 880Z instrument. Standard “cookbook” parameters
were employed, including a wavelength of 283.3 nm, bandpass of 0.5 nm, and Zeeman
background correction. Each solution analyzed included 10 µL of the sample, 10 µL of
deionized water, and 3 µL of a 1% NH4H2PO4 matrix modifier solution to suppress premature
volatilization of lead in the form of PbCl2. GFAAS temperature program parameters include
200ºC dry stage, 825ºC ash stage, 1750ºC atomization stage, and a 2300ºC clean stage. Given
that the samples contained high salt contents, a standard addition-based method was used for
quantitation. Here, lead was quantified by spiking a sample extract with three different levels of
lead and computing the original concentration using linear regression.