Kinetic analytical method for determination of uric acid in human urine using analyte pulse perturbation technique

Abstract

Novos métodos simples e confiáveis para a determinação de ácido úrico (UA) são propostos e validados. Para a determinação quantitativa de UA, duas matrizes foram usadas: a reação oscilatória de Bray-Liebhafsky (BL) em um estado estacionário de não equilíbrio, estável, próximo ao ponto de bifurcação (método A), e o subsistema não oscilante (mistura de KIO 3 e H 2 SO 4), isto é, reação de Dushman (RD) em um estado estacionário (método B). Os métodos propostos são otimizados num reator tanque continuamente agitado (CSTR) e aplicados com excelentes resultados na determinação de UA em amostras de urina humana. A relação linear entre o deslocamento potencial máximo DE m e o logaritmo da concentração de UA (processo A), ou entre DE m e a concentração UA (processo B) é obtido no intervalo de concentração 2,98 × 10-5-2,68 × 10-4 mol L-1 e 2,98 × 10-5-3,58 × 10-4 mol L-1 , respectivamente. Os métodos têm uma velocidade de processamento de amostra excelente de 30 amostras h-1 (método A) e 7 amostras h-1 (método B) com sensibilidade determinada para ser 1,1 × 10-5 mol L-1 (método A) e 8,9 × 10-6 mol L-1 (método B), e precisão RSD ≤ 3.4% para ambos os métodos. Alguns aspectos do possível mecanismo de ação de UA nos sistemas de reação oscilante BL e não-oscilante de Duschman, são discutidos em detalhe. Simple and reliable novel methods for the determination of uric acid (UA) are proposed and validated. For quantitative determination of UA, two matrices were used: the Bray-Liebhafsky (BL) oscillatory reaction in a stable non-equilibrium stationary state close to the bifurcation point (method A) as well as, the BL non-oscillating subsystem (mixture KIO 3 and H 2 SO 4), i.e., Dushman reaction (DR) in a steady state (method B). The proposed methods are optimized in a continuously fed well stirred tank reactor (CSTR) and applied with excellent results in the determination of UA in human urine samples. The linear relationship between maximal potential shift DE m , and both the logarithm of the UA concentration (procedure A) and UA concentration (procedure B) is obtained in the concentration range 2.98 × 10-5-2.68 × 10-4 mol L-1 and 2.98 × 10-5-3.58 × 10-4 mol L-1 , respectively. The methods have an excellent sample throughput of 30 samples h-1 (method A) and 7 samples h-1 (method B) with the sensitivity determined to be 1.1 × 10-5 mol L-1 (method A) and 8.9 × 10-6 mol L-1 (method B) as well as the precision RSD ≤ 3.4% for both methods. Some aspects of the possible mechanism of UA action on the BL oscillating and Duschman non-oscillating reaction systems are discussed in detail.

Determination of experimental conditions for examination of analytes in Bray-Liebhafsky oscillatory reaction in open reactor conditions

“…S obzirom da je BL oscilatorna reakcija i dalje nepoznanica, ponašanje matrice pri perturbaciji analitom, može da doprinese i proširivanju saznanja o samom ocilatornom sistemu. Do sada je BL reakcija, u uslovima otvorenog reaktora, uspešno korišćena za određivanje koncentracije kvercetina [12,13], rutina [14], hesperidina [15], polimernog nosača [16], paracetamola [17], morfina [18], 6-O-acetilmorfina [19], askorbinske kiseline [20] , vitamina B grupe (B1, B2, B3 i B6) [21], mokraćne kiseline [22] i piroksikama [23] Cilj ovog rada je pronalaženje eksperimentalnih uslova u otvorenom reaktoru za ispitivanje širokog spektra analita u BL reakciji. Pronalaženje pomenutih uslova vrši se bifurkacionom analizom i predstavlja prvi korak u ispitivanju analita, njegovih fizičko-hemijskih svojstava, koncentracije, ali i mehanizma delovanja u BL sistemu.…”

Advances made by Belgrade's group in research of oscillatory reactions

“…Furthermore, various methods were developed for formal kinetics of homogenous oscillatory process (Anić et al 1986a;Anić et al 1987;Anić et al 1988;Anić et al 1996;Anić et al 2007), as well as for the stability analysis of the postulated models (Kolar- Anić et al 1995b;Schmitz et al 2000). All investigations were used for different purposes, starting with the development of new analytical methods Pejić et al 2003;Pejić et al 2005;Pejić et al 2006;Pejić et al 2007a;Pejić et al 2007b;Pejić et al 2007c;Pejić et al 2009;Pejić et al 2011;Pejić et al 2012;Pejić et al 2013;Pejić et al 2014a;Pejić et al 2014b;Pejić et al 2016;Vukojević et al 1999;Vukojević et al 2001) and the methods for determining the catalyst's activity Terlecki-Baričević et al 1995;Pejić et al 2001;Anić et al 2009;Maksimović et al 2011), as well as the influence of external fields on the evolution of the chemical oscillator (Stanisavljev et al 2004;Stanisavljev et al 2005;Stanisavljev et al 2006;Stanisavljev et al 2014) to modelling of biochemical processes (Jelić et al 2008;Jelić et al 2009;Čupić et al 2016b;Čupić et al in press;Kolar-Anić 2017d;Marković at. al 2011a;Čupić et al in press;Marković et al 2011b;…”

“…Using them, analyte pulse perturbation techniques (Fig. 4) were developed for determination of paracetamol, ascorbic acide, morphine, 6-monoacetylmorphyne, piroxicam, and also for uric acid in human urine Pejić et al 2007a;Pejić et al 2007b;Pejić et al 2007c;Pejić et al 2012;Pejić et al 2014). …”

Insight into the Origin of Pyrocatechol Inhibition on Oscillating Bray-Liebhafsky Reaction: Combined Experimental and Theoretical Study

“…15 Beside wide scientific interest from the aspects of their unusual dynamics and mechanism, thanks to their great sensitivity to external perturbations, chemical oscillators have also become very popular for analytic determination of "reactive" analyte, usually antioxidant or radical scavenger. [16][17][18][19][20][21] It is well-known that iodate-based oscillatory Briggs-Rauscher (BR) reaction, 22 which is the hybrid of two oscillatory reactions Bray-Liebhafsky (BL) and Belousov-Zhabotinsky 23 (BZ), can be inhibited by small amounts of different perturbants. [19][20][21] Based on this observation, the BR reaction was successfully applied as a test tool for measuring the concentration of different analytes and their potential antioxidative/antiradical activity.…”