Graphene Oxides Coated Paper as a Substrate to Paper Spray Ionization Mass Spectrometry for Creatinine Determination in Urine Samples

Paper spray ionization (PSI) is a promising analytical tool for direct analysis in mass spectrometry (MS). However, this technique usually uses chromatographic paper, which rarely accomplishes a stable MS signal and could vary with the sample matrix effect. In the present study, the application of graphene oxides (GO) was scrutinized as modifier paper substrate for PSI-MS methods. The developed substrate efficiency was evaluated towards creatinine determination in urine samples. The GO-PSI-MS developed method for creatinine in urine samples showed linearity in the range of 0.1 to 3.4 ppm with R2 = 0.9991. The precision was evaluated and the values were between 1.1 to 6.8% and the accuracy above 96.8%. The limit of quantification (LOQ) and limit of detection (LOD) were 0.05 and 0.17 ppm, respectively. The GO-PSI developed was compared to conventional chromatographic paper for PSI-MS methods, and the results showed that the modified paper with GO bolsters method linearity, precision, and LOQ values.

纸喷雾电离（Paper Spray Ionization, PSI）是一种极具应用前景的质谱（Mass Spectrometry, MS）直接分析工具。然而，该技术通常采用色谱滤纸作为基底，不仅难以获得稳定的质谱信号，还易受样品基质效应影响而产生波动。本研究针对PSI-MS分析方法，考察了氧化石墨烯（Graphene Oxides, GO）作为改性滤纸基底的应用效果。以尿液样品中的肌酐定量检测为模型，对所开发基底的分析性能进行了评估。所建立的GO-PSI-MS肌酐检测方法在0.1~3.4 ppm范围内呈现良好线性关系，决定系数R²=0.9991。对方法精密度进行考察，结果介于1.1%~6.8%之间，准确度高于96.8%。定量限（Limit of Quantification, LOQ）与检测限（Limit of Detection, LOD）分别为0.05 ppm与0.17 ppm。将所开发的GO-PSI方法与传统色谱滤纸基底的PSI-MS方法进行对比，结果表明，经GO改性的滤纸可显著提升方法的线性度、精密度与定量限性能。