High-throughput and high-sensitivity quantitative analysis of serum unsaturated fatty acids by chip-based nanoelectrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry: Early stage diagnostic biomarkers of pancreatic cancer

• Published in: Analyst (London) Vol. 139; no. 7; pp. 1697 - 1706
• Main Authors: Zhang, Yaping, Qiu, Ling, Wang, Yanmin, Qin, Xuzhen, Li, Zhili
• Format: Journal Article
• Language: English
• Published: England 07.04.2014
• Subjects: Adult; Age Factors; Aged; Biomarkers - blood; Case-Control Studies; Cyclotrons; Diagnostic systems; Early Diagnosis; Fatty acids; Fatty Acids, Unsaturated - blood; Female; High-Throughput Screening Assays - instrumentation; High-Throughput Screening Assays - methods; Humans; Male; Middle Aged; Nanostructure; Pancreatic Neoplasms - blood; Pancreatitis - blood; Panels; Patients; Polycarbonates; Reproducibility of Results; Sensitivity and Specificity; Serums; Sex Factors; Spectrometry, Mass, Electrospray Ionization - instrumentation; Spectrometry, Mass, Electrospray Ionization - methods; Spectroscopy, Fourier Transform Infrared - instrumentation; Spectroscopy, Fourier Transform Infrared - methods; Unsaturated
• ISSN: 0003-2654; 1364-5528; 1364-5528
• DOI: 10.1039/C3AN02130K

In this study, Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) coupled with chip-based direct-infusion nanoelectrospray ionization source (CBDInanoESI) in a negative ion mode is first employed to evaluate the effect of serum and its corresponding supernatant matrixes on the recoveries of serum free fatty acids (FFAs) based on spike-and-recovery experimental strategy by adding analytes along with analog internal standard (IS). The recoveries between serum (69.8–115.6%) and the supernatant (73.6–99.0%) matrixes are almost identical. Multiple point internal standard calibration curves between the concentration ratios of individual fatty acids to ISs, (C 17:1 as IS of C 16:1 , C 18:3 , C 18:2 , or C 18:1 or C 21:0 as IS of C 20:4 or C 22:6 ) versus their corresponding intensity ratios were constructed for C 16:1 , C 18:3 , C 18:2 , C 18:1 , C 20:4 and C 22:6 , respectively, with correlation coefficients of greater than 0.99, lower limits of detection between 0.3 and 1.8 nM, and intra- and inter-day precision (relative standard deviations <18%), along with the linear dynamic range of three orders of magnitude. Sequentially, this advanced analytical platform was applied to perform simultaneous quantitative and qualitative analysis of multiple targets, e.g. , serum supernatant unsaturated FFAs from 361 participants including 95 patients with pancreatic cancer (PC), 61 patients with pancreatitis and 205 healthy controls. Experimental results indicate that the levels of C 18:1 , C 18:2 , C 18:3 , C 20:4 and C 22:6 , as well as the level ratios of C 18:2 /C 18:1 and C 18:3 /C 18:1 of the PC patients were significantly decreased compared with those of healthy controls and the patients with pancreatitis ( p < 0.01). It is worth noting that the ratio of C 18:2 /C 18:1 , polyunsaturated fatty acids (PUFAs) (C 18:2 , C 18:3 , C 20:4 , and C 22:6 ), panel a (C 16:1 , C 18:3 , C 18:2 , C 20:4 and C 22:6 ) and panel b (C 18:2 /C 18:1 and C 18:3 /C 18:1 ) performed excellent diagnostic ability, with an area under the receiver operating characteristic curve of ≥0.869, sensitivity of ≥85.7%, and specificity of ≥86.7% for differentiating the early stage PC from non-cancer subjects, which are greatly higher than those of clinically used serum biomarker CA 19-9. More importantly, this platform can also provide a fast and easy way to quantify the levels of FFAs in less than 30 s per sample.