Amperometric determination of ammonium with bienzyme/poly(carbamoyl) sulfonate hydrogel-based biosensor

An Optical Based Biosensor for the Determination of Ammonium in Aqueous Environment

“…The K m gives information on the enzyme-substrate kinetics for the biosensor and the values calculated to be at 1.89 mM. The K m value determined with the present biosensor is comparable to the reported value using amperometric detection [2], where the K m of 1.5 mM is obtained utilizing bienzyme system (glutamate oxidase/ glutamate dehydrogenase) immobilized using poly (carbamoyl) sulfonate hydrogel. The reproducibility in the biosensor fabrication was also investigated at respective ammonium, MTT, NADH and α-ketoglutaric acid concentrations of 0.25 mM, 0.30 mM, 0.20 mM and 0.15 mM and it was found to be good with a relative standard deviation (RSD) of 5.46% (n = 6).…”

“…Usually, ammonia exist either in form of gases as ammonia or in water as ammonium ( 4 ) ions [1]. Ammonia is part of the natural nitrogen cycle and it is released to the environment by natural processes such as the decomposition of organic matter, human and animal excrements, or by volcanic eruptions [2]. It can also be distributed to the environment by activities like extensive use of fertilizers, spillage or leakage from wastewater treatment plants [3].…”

“…It can also be distributed to the environment by activities like extensive use of fertilizers, spillage or leakage from wastewater treatment plants [3]. Ammonia is often found at low level in natural water however, elevated concentration of this compound can occur usually due to effluent discharges from sewage treatment plants, industrial processes or farming activeties [2,3].…”

“…These methods are time consuming and often require skill personnel to operate the sample preparation. An interesting alternative method for determination of dissolved ammonia involves the development of biosensors, which can offer simple, rapid, sensitive, specific and portable system [2,3,7].…”

Recent progress in bio-sensing techniques with encapsulated enzymes

“…There are some reports based on the use of sol-gel and hydro-gel matrix with encapsulated enzymes that allows the measurement of low amount of target molecules in real samples such as ammonium in a wastewater (Kwan et al, 2005;Azmi et al, 2009), lactate in dairy products and serum samples (Choi, 2005), cholesterol in human serum (Zhao et al, 2008), uric acid in biological fluids (Martinez-Perez et al, 2003), heavy metals in a tap water (Tsai and Doong, 2005), and hydrogen peroxide in disinfector samples (Li et al, 2008). In most cases, samples were directly diluted by a buffer solution and filtered by a syringe filter for the sample pre-treatment.…”