Applicability of Liquid Chromatography with Time-of-Flight Mass Spectrometric Detection for Determination of Cyanuric Acid in Soil

Sanja Stipičević,Marko Vuletić,Vlasta Drevenkar,Gordana Mendaš,Sanja Fingler

doi:10.5562/cca2109

Abstract

Abstract. Cyanuric acid (2,4,6-trihydroxy-1,3,5-triazine, CA) is a highly polar and hydrophilic degrada-tion product of symmetric triazine herbicides, fairly stable under environmental conditions. We investi-gated the applicability of reversed-phase liquid chromatography coupled to time-of-flight mass spectrome-try (LC-ToF-MS) for qualitative and quantitative determination of CA in soils of different origin and pe-dological characteristics. CA was ultrasonically extracted from soils either with a mixture of acetone and n -hexane (volume ratio = 2:1) or with methanol and analysed on a LiChrospher 100 CN column with ψ(acetonitrile,water) = 50:50 as the mobile phase for isocratic elution. The efficiency and selectivity of LC-ToF-MS determination, using the electrospray ionisation in negative mode and selective monitoring of deprotonated CA molecule ( m/z 128), was evaluated with respect to injection volume, extracting solvent, and possible soil matrix interferences. The advantage of LC-ToF-MS over conventional HPLC with UV-diode array detection was the high ion detection selectivity minimising the interferences of coeluting spe-cies and the unambiguous identification of CA in soil extracts by accurate mass measurements of deproto-nated molecule. (doi: 10.5562/cca2109)

Highlights

Cyanuric acid (2,4,6-trihydroxy-1,3,5-triazine, CA) is a highly polar, hydrophilic compound, fairly stable under many environmental conditions
We reported the mass fractions of CA found in industrial soils that were long contaminated with triazine herbicides
To optimise the high-performance liquid chromatography (HPLC)-UV(DAD) conditions for the determination of CA in soil extracts, the performance of two LC columns of different polarity was compared by analysing CA standard solutions prepared either in LCgrade water or in phosphate buffer

Summary

Introduction

Cyanuric acid (2,4,6-trihydroxy-1,3,5-triazine, CA) is a highly polar, hydrophilic compound, fairly stable under many environmental conditions. CA is a by-product of melamine (2,4,6-triamino-1,3,5-triazine) production, another industrial chemical, and one of the melamine microbial metabolites.[3] In the recent years, both compounds have attracted remarkable attention as potentially harmful adulterants deliberately incorporated in pet food, animal feed, and human food (including infant formula, milk, and milk products) Their role in the mentioned foodstuffs was to increase the calculated apparent protein level by increasing the food total nitrogen content.[4] When combined, CA and melamine can form crystals of insoluble melamine cyanurate via hydrogen bonding, whose deposition in kidneys leads to renal failure.[4,5,6]

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