Ultratrace Determination of Lead in Whole Blood Using Electrothermal Atomization Laser-Excited Atomic Fluorescence Spectrometry

Abstract

Laser-excited atomic fluorescence has been used to detect lead that was electrothermally atomized from whole blood in a graphite furnace. A 9 kHz repetition rate copper vapor laser pumped dye laser was used to excite the lead at 283.3 nm, and the resulting atomic fluorescence was detected at 405.8 nm. No matrix modification was used other than a 1:21 dilution of the whole blood with high-purity water. Using the atomic fluorescence peak area as the analytical measure and a background correction technique based upon a simultaneous measurement of the transmitted laser intensity, excellent agreement for NIST and CDC certified whole blood reference samples was obtained with aqueous standards. A limit of detection in blood of 10 fg/mL (100 ag absolute) was achieved.

Determination of Lead in Whole Blood by Filter Furnace Laser-Excited Atomic Fluorescence Spectrometry

“…Laser-excited atomic fluorescence using a copper vapor laser has proven to be a very sensitive method for the determination of lead where a limit of detection of 0.1 fg has been reported in a previous study made in our laboratory 4 , in contrast to 5 pg that can be achieved by graphite furnace atomic absorption spectrometry. 2 Taking advantage of this high sensitivity, the amount of blood deposited in the filter furnace was reduced to 1 µl to minimize the amount of organic matter and the amount of fumes released.…”

“…The difference in intensities in this case can be attributed mainly to the attenuation of the excitation laser radiation as well as the emitted fluorescence by the smoke released and to fluorescence quenching of excited species by the high concentration of molecular species in the analytical zone during atomization. 4 With the filter furnace technique, several heating programs were evaluated. The best program (Table 1) included a pre-atomization cycle with two drying steps and a low temperature ashing step (300˚C), to avoid the problems related to the use of the high temperature preatomization discussed above.…”

“…4 A platform, which delays the atomization of the analyte until a temperature equilibrium is reached between the walls and the center of the tube, in many cases is a very useful approach to minimize problems related with the formation of compounds after the vaporization of highly volatile and medium volatile elements. Chemical modifiers can chemically transform the analyte of interest making it less volatile, and so higher ashing and/or atomization temperatures can be applied.…”

“…Ideally, a method to analyze complex samples should allow the correlation of complex standards to aqueous standards simplifying the calibration curve procedure by eliminating the need for blood standards. In previous work by Wagner et al 4 , correlation was successfully accomplished for lead by using a photodiode placed behind the furnace, in line with the laser beam, correcting for the decrease of laser intensity of the sample relative to the blank. Potentially, the Katskov filter is a cheaper and simpler alternative to achieve such correlation of standards.…”

Colorimetric assay of lead using unmodified gold nanorods

“…To monitor Pb 2+ level, several methods have been developed, including inductively coupled plasma mass spectrometry [6,7], atomic fluorescence spectrometry [8,9], atomic absorption spectroscopy [10], reversed-phased high-performance liquid chromatography [11], and so on. Even with sensitivity and accuracy, there also share some disadvantages, such as timeconsuming, expensive, and/or require sophisticated equipment, etc.…”