Abstract: Turbomixers were studied as replacements for mixing coils in flow injection methods for the determination of O3, ClO2-, ClO3-, Kjeldahl N, NO2- and phosphate. The limits of detection and coefficient of variation were generally comparable with or better than those obtained by standard flow injection analysis and sample throughput was 10% higher. The mixers removed the need for circular, serpentine or knotted coils. This paper describes an investigation of turbomixer as replacements for mixing coils in flow injection analysis (FIA). The turbomixer is a device that will efficiently mix three streams simultaneously. Although the traditional FIA gradient is not produced, the data shows that the reproducibility of a turbomixer-continuous-flow system is comparable to a standard FIA system.

Abstract: A non-polluting alternative catalyst was used in a U.S. Environmental Protection Agency (EPA) Kjeldahl digestion procedure for water and wastewater samples. The colorimetric semiautomated block digestion method (EPA Method 351.2) was essentially unchanged except that 1 mL of a saturated solution of titanium dioxide was added to the digestant mixture, instead of 2 g mercuric oxide. Titanium dioxide is a nontoxic compound, which makes an excellent replacement in total Kjeldahl nitrogen (TKN) determination. Samples were digested and then placed on a flow injection autoanalyzer for ammonia determination. All other digestion and analysis procedures were the same as in the original method. Detection limit for TKN was 0.1 mg/L. Recovery of glutamic acid averaged 96.2%. Recoveries of standard reference water samples over a 9 month period averaged >95%. (14 References)