A comparison of UV (254nm) absorption spectrometry, optical fluorescence (excitation at 340nm, emission measurement at 420nm) and established chemical methods for estimating Total Organic Carbon (TOC) in water samples obtained from a variety of sources has been made. In addition, a proprietary UV in-line absorption monitor commonly used in industry is assessed relative to these measurements. The work has shown a strong correlation between Total Organic Carbon (TOC) measurements and both UV absorption and fluorescence measurements. These measurements indicate the feasibility of both approaches in the design of new field based instruments for TOC determination using optoelectronic devices.