Influence of water content on the laser-induced breakdown spectroscopy analysis of human cell pellet

• The influence of water content on the LIBS spectra of human cell pellet is investigated.
• Intensity and intensity ratio of LIBS spectra changed significantly by water content.
• Emission lines whose intensity ratio became independent of water contents were identified.

The effects of water content change in a biological sample on the emission signal intensity and intensity ratio during LIBS analysis were investigated. To examine the effects of water content only avoiding matrix effects, a homogeneous human cell pellet consisting of cultured human immortalized keratinocyte cell only was used as the sample. LIBS spectra of the human cell pellet sample produced with a Q-switched Nd:YAG laser (λ = 532 nm, τ = 5 ns, top-hat profile) and a six-channel CCD spectrometer (spectral range = 187–1045 nm, spectral resolution = 0.1 nm) revealed that most of the emission lines observed from a tissue sample were also observable from the human cell pellet. The intensity and intensity ratio of the emission lines varied significantly as the water content of the human cell pellet was changed. It was found that a typically selected internal standard in LIBS analysis of biological samples such as carbon could produce inconsistent results, whereas the ratio of properly selected emission lines such as Mg(II) 280.270 nm and Ca(II) 396.847 nm was nearly independent of sample water content.