Monitoring of trace elements in breast milk sampling and measurement procedures

Area of Science:

• Environmental Science
• Analytical Chemistry
• Human Nutrition

Background:

• Breast milk composition is crucial for infant nutrition and health.
• Monitoring trace elements in breast milk requires validated analytical methods and optimal sampling strategies.
• Understanding element dynamics postpartum is vital for assessing infant exposure and maternal nutritional status.

Purpose of the Study:

• To validate analytical procedures for determining cadmium (Cd), copper (Cu), manganese (Mn), lead (Pb), selenium (Se), and zinc (Zn) in human breast milk.
• To establish optimal sampling conditions for biological monitoring of these elements.
• To investigate the temporal changes and factors influencing element concentrations in breast milk.

Main Methods:

• Microwave-assisted acid digestion (HNO3 + H2O2) of breast milk samples.
• Atomic absorption spectrometry (AAS) with optimized techniques: electrothermal atomization (ETA-AAS) for Cd, Mn, Pb; flame AAS for Cu, Zn; hydride generation (HG-AAS) for Se.
• Analysis of breast milk from two groups: a longitudinal study (n=7) and a cross-sectional study (n=200) across different regions and time points postpartum.

Main Results:

• Optimized analytical methods demonstrated reliable quantification of target elements.
• Zinc and manganese concentrations decreased sharply in early postpartum days, while copper showed a slight initial increase followed by a decrease.
• Selenium levels remained stable; cadmium and lead were mostly below detection limits. Whole milk had higher selenium than skim milk.
• Element concentrations stabilized after approximately 20 days postpartum, with no significant correlations found among elements.

Conclusions:

• Validated analytical procedures and optimized AAS techniques are effective for breast milk element analysis.
• Temporal dynamics of essential elements like Zn, Mn, and Cu in early postpartum breast milk are significant.
• Consistent sampling conditions, particularly the timing of collection, are critical for accurate biological monitoring of breast milk composition.