Flame and Electrothermal Atomic Spectrometry

Regarding FAAS, only a study by Flores et al. [74] employed PLS to quantify Cd in marine and river sediments measured by direct solid sampling FAAS. 

ETAAS was also combined with PLS by Baxter et al. [76] to determine As in marine sediments. They demonstrated that the classical standard additions method does not correct for spectral interferences (their main problem) because of mutual interactions between the two analytes of interest (As and Al). PLS-2 block was applied to quantify simultaneously both elements (PLS-2 block is the notation for the PLS regression when several analytes are predicted simultaneously it is not widely applied, except when the analytes are 

Since the work of Baxter et al. [75,76] around 1990, we have not found many more recent applications and it was not until 2003 that Felipe-Sotelo et al. [77] presented another application. They considered a problem where a major element (Fe) caused spectral and chemical interferences on a minor element (Cr), which had to be quantified in natural waters. They demonstrated that linear PLS handled (eventual) nonlinearities since polynomial PLS and locally weighted regression (nonlinear models) did not outperform its results. Further, it was found that linear PLS was able to model three typical effects which currently occur in ETAAS peak shift, peak enhancement (depletion) and random noise. 

Inductively coupled plasma (ICP) needs careful extraction of the relevant information to obtain satisfactory models and several chemometric studies were found. Indeed, many ICP spectroscopists have applied multivariate regression and other multivariate methods to a number of problems. An excellent review has recently been published on chemometric modelling and applications of inductively coupled plasma optical emission spectrometry (ICP-OES) [79]. 

Moberg et al. [90] used ICP-MS to determine Cd in fly ash and metal alloys since severe spectral overlaps arose, multivariate regression outperformed other univariate approaches. They also studied whether day-to-day ICP-MS recalibration could be avoided so that the calibration set could be constructed on several runs. 

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Flame and Electrothermal Atomic Spectrometry (FAAS and ETAAS)... 

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