Trace elements and minerals are compounds that are essential for the support of a variety of biological functions and play an important role in the formation of and the defense against oxidative stress. Here we describe a technique, allowing sequential detection of the trace elements (K, Zn, Se, Cu, Mn, Fe, Mg) in serum and whole blood by an ICP-MS method using single work-up, which is a simple, quick and robust method for the sequential measurement and quantification of the trace elements Sodium (Na), Potassium (K), Calcium (Ca), Zinc (Zn), Selenium (Se), Copper (Cu), Iron (Fe), Manganese (Mn) and Magnesium (Mg) in whole blood as well as Copper (Cu), Selenium (Se), Zinc (Zn), Iron (Fe), Magnesium (Mg), Manganese (Mn), Chromium (Cr), Nickel (Ni), Gold (Au) and Lithium (Li) in human serum. For analysis, only 100 μl of serum or whole blood is sufficient, which make this method suitable for detecting trace element deficiency or excess in newborns and infants. All samples were processed and analyzed by ICP-MS (Agilent Technologies). The accuracy, precision, linearity and the limit of quantification (LOQ), Limit of Blank (LOB) and the limit of detection (LOD) of the method were assessed. Recovery rates were between 80-130% for most of the analyzed elements; repeatabilities (C v %) calculated were below 15% for most of the measured elements. The validity of the proposed methodology was assessed by analyzing a certified human serum and whole blood material with known concentrations for all elements; the method described is ready for routine use in biomonitoring studies.

Obstructive sleep apnea (OSA), independently of obesity (OBS), predisposes to insulin resistance (IR) for largely unknown reasons. Since OSA-related intermittent hypoxia triggers lipolysis, overnight increases in circulating free fatty acid (FFA) including palmitic acid (PA) may lead to ectopic intramuscular lipid accumulation potentially contributing to IR. Using 3-T-1H-magnetic-resonance-spectroscopy, we therefore compared intra- and extra-myocellular lipid (IMCL and EMCL) in vastus lateralis muscle at ~7:00 a.m. between 26 male patients with moderate-to-severe OSA (17 obese, 9 non-obese) and 23 healthy male controls (12 obese, 11 non-obese). Fiber type composition was evaluated by muscle biopsies. Moreover, we measured fasted FFA including PA, HbA1c, thigh subcutaneous fat volume (ScFAT, 1.5-T-magnetic-resonance-tomograpphy) and maximal oxygen uptake (VO2max). 14 patients were reassessed after continuous-positive-airway-pressure (CPAP) therapy. Total FFA and PA were significantly by 178% and 166% higher in OSA patients vs. controls and correlated with the apnea-hypopnea index (AHI) (r≥0.45, P<0.01). Moreover, IMCL and EMCL were 55% (P<0.05) and 40% (P<0.05) higher in OSA patients, i.e. 114% and 103% in non-obese, 24.4% and 8.4% in obese subjects (with higher control levels). Overall, PA, FFA (minus PA) and ScFAT significantly contributed to IMCL (multiple r=0.568, P=0.002). CPAP significantly decreased EMCL (-26%) and, by trend only, IMCL, total FFA and PA. Muscle fiber composition was unaffected by OSA or CPAP. Increases in IMCL and EMCL are detectable at ~7:00 a.m. in OSA patients and partly attributable to overnight FFA excesses and high ScFAT or BMI. CPAP decreases FFAs and IMCL by trend but significantly reduces EMCL.

In this work, we describe a simple, fast, cheap, accurate and high-throughput method for the determination of Al; V; Cr; Mn; Fe; Co; Cu; Zn; As; Se; Mo; Cd; Sn; Ba; TI; Pb in a micro volume of urine by using inductively coupled mass spectrometry (ICP-MS) equipped with an octupole-based collision cell. The samples were directly analyzed after a simple acidification with 3% nitric acid. Validation of this method was performed by using certified urine reference material. He and H were used as collision gas for reducing polyatomic interference for most of the measured elements. Finally, we partook in an external quality assurance conducted by ISNTAND e.V. 2. Results show that our high-throughput method is ideal for detecting elements in newborns and infants because of its simplicity, speed, accuracy and low sample volume.