Quantitative analysis of galactose using LDI-TOF MS based on a TiO2 nanowire chip

Joo-Yoon Noh,Tae Gyeong Yun,Jae-Chul Pyun,Moon-Ju Kim,Jong-Min Park,Jo-Il Kim,Mira Kim,Min-Jung Kang

doi:10.1186/s40543-021-00300-7

Abstract

A novel method for quantifying galactose was developed to serve as a newborn screening test for galactosemia using laser desorption/ionization time-of-flight (LDI-TOF) mass spectrometry (MS) with a TiO2 nanowire chip. Herein, phosphate citrate buffer, serum, and dried blood spot (DBS) were employed for the quantitative analysis of galactose. To quantitatively analyze galactose, its reduction potential was used to oxidize o-phenylene diamine (OPD) into 2,3-diaminophenazine (DA), which were both detected using LDI-TOF MS with a TiO2 nanowire chip according to the concentration of galactose. The reproducibility and the interference of glucose were determined to demonstrate the applicability of this method. Moreover, mixtures of galactose, phenylalanine, and 17 α-OHP were analyzed to determine the interference induced by other biomarkers of metabolic disorders. The OPD oxidation of galactose was found to be selectively achieved under high-glucose conditions, similar to human blood, thereby showing good reproducibility. The intensities of the mass peaks of OPD and DA based on LDI-TOF MS with a TiO2 nanowire chip were linearly correlated in the galactose concentration range of 57.2–220.0 μg/mL (r2 = 0.999 and 0.950, respectively) for serum samples and 52.5–220.0 μg/mL (r2 = 0.993 and 0.985, respectively) for DBS after methanol precipitation/extraction. The enzyme immunoassay and LDI-TOF MS analysis results were statistically analyzed, and a mixture of phenylalanine, 17 α-OHP, and galactose was simultaneously investigated quantitatively at the cutoff level.

Highlights

Detection of galactose is important in many fields, including food science, medicine, and nutrition (Alm 1982; Nguyen et al 2020; Rajendran and Irudayaraj 2002; Kaarj et al 2020)
The results for phenylalanine and 17-α-OHP as the concentration-variable analytes showed the same trend (Fig. 6c, d). These results demonstrate that other biomarkers did not interfere in the analysis of galactose and the diagnosis of newborn metabolic disorders could be simultaneously be established using the multiplex test platform with MALDI-TOF mass spectrometry (MS) based on a TiO2 nanowire chip
In this study, galactose in dried blood spot (DBS) was quantified in a newborn screening test using MALDI-TOF MS based on TiO2 nanowire chip to diagnose galactosemia

Summary

Introduction

Detection of galactose is important in many fields, including food science, medicine, and nutrition (Alm 1982; Nguyen et al 2020; Rajendran and Irudayaraj 2002; Kaarj et al 2020). Newborn screening tests have been employed to diagnose many types of fatal diseases; these tests involve the analysis of essential metabolites involved in their growth, such as amino and fatty acids (Naylor and Chace 1999; Paul 2008; Pitt 2010; Ryckman et al 2013; Saudubray et al 2002). Newborn screening tests involving the analysis of amino and fatty acids have been extensively conducted using liquid chromatography with tandem mass spectrometry (LC–MS/MS) (Kaye et al 2006; Lee 2006; Li and Tse 2010; Shim et al 1999). Developing a simple, sensitive, single test platform for effective newborn screening tests is highly required for total and simultaneous analyses of the targeted metabolite repertoire, from small molecules (amino acids, fatty acids, and monosaccharides) to large proteins

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Conclusion