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Abstract

Human biomonitoring is a scientific technique that allows us to assess whether and to what extent particular environmental substances have entered our bodies and how our exposure to them is changing over time. Polybrominated diphenyl ethers (PBDEs) and Cr(VI) were both identified as priority substances in the European human biomonitoring initiative (HBM4EU) because of their well-known toxicity and presence in the environment. In order to reliably determine these substances in different environmental and biological samples, simple, sensitive and robust analytical methods must be developed. Such methods provide important data to our knowledge on the behavior of potentially toxic substances in the environment and in the human body.
Polybrominated diphenyl ethers (PBDEs) are flame retardants that are added to a wide range of consumer products. Due to their extensive use in the past, their presence has been documented in multiple environmental compartments and living organisms, including humans. Most analytical procedures for the determination of PBDEs in human serum require large amounts of sample and tedious clean-up steps that consume large amounts of organic solvents. Therefore, a new simple, reliable, and sensitive method was developed for the determination of six PBDE congeners (BDE 28, BDE 47, BDE 99, BDE 100, BDE 153, BDE 154) in human serum by gas chromatography–inductively coupled plasma mass spectrometry (GC-ICP-MS). The PBDEs were extracted from 1 mL of serum by 30 min of mechanical shaking with 1 mL of formic acid. Subsequently, 2 mL of iso-octane was added and 30 min of mechanical shaking applied. For clean-up of the extract, Florisil column was applied. The analytical method was validated by analysis of human serum standard reference materials SRM 1957 (Non-Fortified Human Serum) and SRM 1958 (Fortified Human Serum). The results showed that the method is accurate, repeatable and reproducible. The limits of detection (LODs) for the PBDEs analyzed were between 0.0016 and 0.0039 ng mL-1 wet weight (ww). The feasibility of the method was tested by analyzing human serum samples. The determined concentrations were similar to those reported for certain other European countries.
Although the transport and interactions of Cr species with blood constituents have attracted the interest of researchers, there are only a few studies available on Cr speciation in the human serum. Therefore, in order to investigate the kinetics of interactions of Cr(VI) and Cr(III) with serum constituents, and to perform Cr speciation at physiological concentration levels, a novel analytical method based on monolithic convective interaction media (CIM) chromatography coupled to UV and inductively coupled plasma mass spectrometry (ICP-MS) detectors was developed. Cr(VI) was separated from Cr-transferrin (Cr-Tf) and Cr-albumin (Cr-HSA) on a CIM diethylamino (DEAE) column using linear gradient elution from 100% buffer A (50 mM Tris-HCl + 10 mM NaHCO3, pH 7.4) to 60% buffer B (buffer A + 2 M NH4Cl) in 10 min at a flow rate of 1 mL min-1. Good column recovery of separated Cr species (close to 100%) and satisfactory method repeatability (RSDs below 8%) was obtained. Kinetics of interaction of Cr(VI) and Cr(III) with serum constituents was followed after the human serum was doubly spiked with enriched 50Cr(VI) and 53Cr(III) solutions, and speciation analysis applied from 5 min up to 48 h after spiking. The results showed that in the serum, 53Cr(III) rapidly interacted with Tf, while 50Cr(VI) reduction was slow. 48 h after spiking, more than 90% of added 53Cr(III) was bound to Tf and the remaining 10% associated with HSA. About 20% of spiked 50Cr(VI) was still present in the serum, while the resulting 50Cr(III) was bound predominantly to Tf. High sensitivity of the developed speciation procedure enabled the detection of the Cr-Tf complex as the main Cr species in the human serum at physiological concentration levels.