A study of the distribution of aluminium in human placental tissues based on alkaline solubilization with determination by electrothermal atomic absorption spectrometry

Abstract

Aluminium (Al) is a nonessential element known to induce neurotoxic effects, such as dialysis dementia, in patients on hemodialysis, with compromised kidney function. The role of Al in the progression of some neurodegenerative diseases, such as Alzheimer's disease (AD), is controversial, and remains unclear. The effects of Al on other vulnerable populations, such as fetuses and infants, have been infrequently studied. In the present study, Al has been measured in human placenta samples, comprising ∼160 each of placenta bodies, placenta membranes, and umbilical cords, using electrothermal atomic absorption spectrometry (ETAAS) after atmospheric pressure digestion with tetramethylammonium hydroxide (TMAH) and ethylenediaminetetraacidic acid (EDTA). The sensitivity, or characteristic mass (m(0)), for Al at the 309.3-nm line was found to be 30 ± 4 pg. The instrumental detection limit (IDL) (3s) for Al in solution was calculated as 0.72 μg L(-1) while the method detection limit (MDL) (3s) was 0.25 μg g(-1). Accuracy was assessed through analysis of quality control (QC) materials, including certified reference materials (CRMs), in-house reference materials (RMs), and spike recovery experiments, of varying matrices. Placental tissue analyses revealed geometric mean concentrations of approximately 0.5 μg g(-1) Al in placenta bodies (n = 165) and membranes (n = 155), while Al concentrations in umbilical cords (n = 154) were about 0.3 μg g(-1). Al was detected in 95% of placenta bodies, and 81% of placenta membranes, but only in 46% of umbilical cords.

Figure 1

Pyrolysis (a) and atomization (b) curves for a placenta body digest containing approximately 13.3 μg L^-1 Al (133 pg). The filled symbols denote optimal temperatures chosen for the determination of Al in placental tissue.

Figure 2

Al distribution in (a) placenta body, (b) placenta membrane, and (c) umbilical cord tissue samples.

Figure 3

Scatter dot plot showing geometric mean and range for Al (μg g^-1) in each placental tissue component. Each data point represents the average Al concentration measured by duplicate analysis of a sample. Black horizontal lines indicate geometric mean concentrations for each sample component. Numbers in parentheses indicate the number of placenta samples analyzed for each component.