Table 4.

Comparison of the equilibrium spectrophotometric methods for NAC and MPG determination.

Analyte	Reagent(s) used	λ max (nm)	Beer's law range (μM)	ε (M−1 cm−1)	Reference
NAC, MPG, penicillamine	Fe(III)/1,10-phenanthroline	515	4.0–80.0	1.1 × 104	[24]
NAC	PdCl2	375	24.5–400.0	Not reported	[23]
NAC	o-phthalaldehyde/isoleucine	335	3.0–300.0	6.3 × 104	[22]
Cysteine, NAC	Fe(III)/ferrozine	562	0.1–36.8	2.3 × 104	[21]
NAC	IO3 −/leucoxylenecyanol	613	1.2–9.8	9.6 × 104	[19]
NAC MPG	Fe(III)/TPTZ	593	1.0–100.0	2.2 × 104	Present work