A llquld chromatographic system, capable of selectlvely detecting individual phenolic compounds at 1-ppb levels in water, is described. A polymeric-cation-exchange resin column, acidic acetonitrile-water eluent, and an electrochemical detector containing a unique carbon-black/polyethylene tubular anode are employed. Various types of carbon electrodes have been evaluated, as well as elution order and detector sensitivities for numerous phenolic compounds. Applications of the system to water analyses are presented.Phenolic compounds, especially halogenated ones, are of concern in the environment because of their toxicity to fish and other aquatic life and their adverse affect on water and fish taste ( I ) . Colorimetric analysis with 4-aminoantipyrene usually is employed to measure total phenols (2). However, most para-substituted phenols will not respond adequately, and no information concerning identity is obtained. T o identify and quantitatively measure total phenols a t ppb levels, procedures generally involve solvent extraction and either extensive solvent concentration followed by gas chromatography/mass spectrometry (GC/MS) or selective derivatization and GC with electron capture detection ( 3 ) . Disadvantages of the GC methods are sample preparation time, cost of MS equipment, incomplete recoveries for most phenols, and the lack of detector selectivity when only phenols are desired.A variety of liquid chromatographic (LC) columns have been used to separate mixtures of phenols in water samples (4-8). A major consideration when choosing a column for waste stream analysis is long term stability. Experience in our laboratories (9, IO) and studies by Walton et al. (11,12) have shown that good chromatographic resolution can be obtained with styrene-divinylbenzene base cation-exchange resins. Also these resins are totally unaffected by repeated injections of strong acids, bases, or concentrated brine solutions. If necessary, the columns can be emptied, cleaned, and refilled easily.Electrochemical detection of phenols after LC separation was demonstrated in 1973 by Takata and Muto (7). Since then, numerous publications describing electrochemical cell constructions and applications have appeared in the literature and were reviewed by Kissinger through December 1977 (13-15). Until recently, the material of choice for oxidative working electrodes was carbon paste. It is inert, easily replaced when fouled, and yields a low and stable residual current. However, it is unsuitable for LC eluents containing appreciable methanol or acetonitrile because the organic binder of the paste dissolves. Thus, a more universally applicable anode material is required.Glassy carbon is presently the alternative anode material of choice. It performs well in an electrochemical detector once the surface has been rigorously polished (16). In our experience, the electrode will become passivated during wastewater analysis and provision must be made for renewing the surface when this occurs.We were searching for an anode material that possess...

The diffusion of styrene vapor in ethyl cellulose film has been studied as a function of styrene solubility in the film at 50°C. Methods and data are presented for determining the equilibrium solubility of styrene in ethyl cellulose as a function of vapor pressure at 50°C. The permeation rates of styrene vapor through 3‐mil film were determined under steady state conditions for various pressures of pure styrene vapor on one side of the film and vacuum on the other side. From a plot of permeation rates versus styrene solubility the diffusion coefficient was calculated as a function of concentration. Measurements made over a concentration range of 0 to 0.7 g. styrene/cm.3 of unswollen film show that the diffusion coefficient first increases rapidly with concentration, then goes through a maximum, and finally levels off at 10−7 cm.2/sec. In the limited range of 0.06 to 0.10 g./cm.3 the diffusion coefficient varies exponentially with concentration as has been reported for other systems in a similar range. However, such a functionality does not represent the present system over a broad concentration range. These results, if generally applicable to other systems, indicate that the nature of the diffusion process for organic vapors in polymers may be considerably more complicated than formerly supposed.