Development of a Simple and Fast Electrochemical Method to Evaluate Physical Stress in Athletes

Abstract

This work describes a simple and fast electrochemical method to evaluate the level of physical stress in athletes by monitoring total proteins in saliva. The proposed system is based on FIA with multiple pulse amperometric detection (FIA/MPA) using gold as the working electrode and 0.1 mol L À1 NaOH as the unique reagent. The proposed method is economical, fast (110 injections per hour) and allows the analysis of a small amount of saliva (~32 mL) with no sample treatment (just dilution). The results obtained by FIA/MPA were compared with the reference spectrophotometric method (Bradford) and a good agreement was found (r = 0.967; p < 0.05). In order to investigate a portable system to determinate physical stress, the electrodes were adapted to a batch injection analysis system (BIA) and the current signals of total proteins in saliva were obtained, similar to FIA.

Electrochemical Determination of the Steroid Tibolone and Its Metabolites in Saliva Samples

“…Saliva samples were collected after informed consent was obtained from healthy people (after mouth rinse) using the Salivette device (Sarstedt AG & Co; Nümbrecht ‐ Germany). Salivette is designed as a synthetic swab which was inserted in the mouth and chews it for about two minutes to stimulate salivation [25] . After that, the swab with the absorbed saliva was placed in the Salivette tube for centrifugation at 5000 rpm for 2 minutes and volumes were collected in the range between 1 to 2 mL.…”

“…Salivette is designed as a synthetic swab which was inserted in the mouth and chews it for about two minutes to stimulate salivation. [25] After that, the swab with the absorbed saliva was placed in the Salivette tube for centrifugation at 5000 rpm for 2 minutes and volumes were collected in the range between 1 to 2 mL. The saliva samples were directly 2-fold diluted in supporting electrolyte (sample pretreatment step).…”

“…Recently, competitive advantages of electrochemical methods have been successfully explored for analysis of drugs and other compounds in saliva samples. [13,[24][25][26][27][28][29][30][31][32] Boron-doped diamond (BDD) has become an important material applied in electrochemistry and electroanalysis. [33][34][35] In fact, its properties are different from other commonly used carbonaceous electrodes, such as favorable electron-transfer kinetics, a wide potential range in aqueous solution (oxygen evolution at~2.0 V), low and stable background current, high corrosion resistance, good resistance to adsorption of molecules and stability in successive measurements.…”

“…According to our knowledge, no electrochemical studies were reported before for the determination of TIB or its metabolites. Recently, competitive advantages of electrochemical methods have been successfully explored for analysis of drugs and other compounds in saliva samples [13,24–32] …”

Determinação de besilato de amlodipina e atenolol utilizando eletrodo de diamante dopado com boro e análise por injeção em batelada com detecção amperométrica

“…Um dos problemas recorrentes do sistema BIA empregando eletrodos sólidos e detecção eletroquímica é o de contaminação/adsorção de componentes na superfície do eletrodo de trabalho. Esse problema pode ser contornado, em sistemas hidrodinâmicos, pela aplicação repetitiva e alternada de pulsos de potenciais de limpeza (detecção amperométrica pulsada) [63,[81][82][83]. Entretanto, a amperometria pulsada tem sido pouco utilizada como modo de detecção em sistemas BIA [49,84], talvez devido à maioria dos estudos empregando BIA com detecção amperométrica terem sido realizados com a solução no interior da célula no estado estacionário, sendo que a limpeza eletroquímica é mais eficaz com o meio (solução) em agitação.…”