Infrared pulsed fiber laser-produced gold and silver-109 nanoparticles for laser desorption/ionization mass spectrometry of steroid hormones.

ABSTRACT

RATIONALE Hormones are compounds that perform many important functions in the human body, but above all their task is to maintain homeostasis by adapting them to the constantly changing environmental conditions. Even minor hormonal disorders have a negative effect on the body, leading to physical or mental changes. Therefore, monitoring these changes and precise quantification of hormones are essential for the early diagnosis of diseases related to hormonal disorders. METHODS: Application of monoisotopic silver-109 and gold nanoparticles obtained by PFL (pulsed fiber laser) 2D GS (galvo-scanner) LGN (laser-generated nanomaterial) for high-resolution laser desorption/ionization mass spectrometry (LDI-MS) and mass spectrometry imaging (MSI) of steroid hormones is presented. Four steroid hormones, estrone, prednisolone, corticosterone and progesterone, were used as test compounds for quantitative analysis with matrix-assisted LDI time-of-flight MS apparatus. Moreover, comparison of manual measurements and semiautomatic MSI with both types of nanoparticles was performed. Methods were also tested on spiked human blood serum for quantification of steroid hormones and for estimation of the matrix effect. RESULTS: Hormones were directly tested in 1 000 000-fold concentration change conditions ranging from 1 mg/mL to 1 ng/mL which equates to 300 ng to 300 fg of hormone per measurement spot. For almost all tested hormones MSI allowed one to obtain equal or lower limit of detection value than manual LDI-MS. The best results judged by lowest limit of detection values are found for silver-109 nanoparticles. CONCLUSION: The results of the quantitative analysis of steroid hormones using silver-109 and gold nanoparticles prepared with PFL 2D GS LGN for LDI-MS and semiautomatic LDI-MSI are presented. It has been proven that nanoparticles obtained by laser synthesis can be successfully used for the analysis of steroid hormones in a wide range of concentrations.