Over a period of time, various newer techniques and analytical tools, such as spectroscopy (e.g., ORAC, DPPH, ABTS, FRAP), electro-chemical methods (e.g., voltammetry, amperometry
), and chromatography techniques (e.g., gas chromatography, high-performance liquid chromatography) have been developed to determine the antioxidant profile of various ingredients."
Chemiluminescence (in liquid-phase) is the fourth most widely employed detection system in FI techniques after UV/Visible, fluorescence and amperometry
The limit of detection for the proposed method was lower or comparable with the methods such as fluorescence, amperometry
, and potentiometry (Table 1).
The electrode arrays detected dopamine, norepinephrine, and 5-hydroxytyramide using linear sweep voltammetry, amperometry
, and cyclic voltammetry over a 16-day period.
Differential pulse amperometry
(DPA) is a technique described and first applied by Marcenac and Gonon in 1985 .
But the main advantage is the high electrocatalytic activity of the foamed porous electrode that caused an important shift of the catechol peak from +0.70 V to +0.25 V that can reduce considerably the potential that needs to be applied in the working conditions of amperometry
. This electrocatalytic effect has been illustrated in Figure 6(b), where the SWV recorded for the same concentration of catechol and hydroquinone (1.92 and 2 mM, resp.) is displayed.
While techniques such as fluorescence and amperometry
provide highly sensitive measurements, only a select number of analytes are fluorescent or electrochemically active.
[H.sub.2]S production by recombinant human CBS variants was measured at 37[degrees]C, either by amperometry
using a [H.sub.2]S-selective electrode (World Precision Instruments) or by the lead acetate method .
The topics include cortical colinergetic transients for cue detection and attentional mode shifts, quantitative chemical measurements of vesicular transmitters with single-cell amperometry
and electrochemical cytometry, coupling voltammetry with optogenetics to reveal axonal control of dopamine transmission by striatal acetycholine, characterizing neuropeptide release from isolated cells to intact animals, and improving the chronic intracortical electrode recording function.
In biomedicine and food industry known is the electrochemical method of catalase-positive microorganisms' detection and identification, developed on the EIA and amperometry
basis for highsensitivity enzymes detection .