United States Environmental Protection Agency Environmental Monitoring and Support Laboratory Cincinnati OH 45268 Research and Development EPA-600/S4-85-001 Feb. 1985 Project Summary Evaluation of EPA Method 603 (Modified) S. V. Lucas. T. F. Cole, A. Riggin, and W. M. Cooke EPA Method 603 was modified and evaluated with newly established chro- matographic conditions for the deter- mination of acrolein, acrylonitrile, and acetonrtrile. The recommended chroma- tographic column and conditions speci- fied in the original method were found to be unsuitable when acetonitrile was included as a method parameter. Pora- pak QS wa» found to perform well as a gas chromatography (GC) packing for the three method parameters, and method validation using reagent water. Publicly Owned Treatment Works (POTW) outfall water, and industrial wastewater was successfully perform- ed. Recoveries and precisions were determined at two spiking levels in each of the three matrices. Seven replicates were analyzed for each of the six spike- level/matrix sets. For acetonitrile, recoveries for the six sets ranged from 86 to 111 percent (average. 99 percent), with precisions ranging from 3 to 17 percent relative standard deviation (RSD), (average, 11 percent RSD). The corresponding values for acrylonitrile were recoveries ranging from 84 to 104 percent (average, 97 percent) and pre- cisions ranging from 3 to 8 percent RSD (average. 4 percent RSD). Acrolein was unstable in the industrial waste- water, even though the water was buffered at pH 4.5 before spiking. For the other two matrices, the acrolein recovery ranged from 80 to 104 percent (average, 94 percent) and the precisions ranged from 1 to 4 percent RSD (average, 3 percent RSD). The loss of acrolein due to apparent chemical or biological degradation in the industrial wastewater underscores the current lack of understanding of the chemical factors that control the stability of acrolein in aqueous systems. All of the data sets were quantified using both an internal standard method and an ex- ternal standard method, and both methods of quantification provided essentially identical accuracy and pre- cision results. This report was submitted in partial fulfillment of Contract Number 68-03- 1760, Work Assignment Number 5, by Battelle's Columbus Laboratories. The research reported here was conducted under the sponsorship of the U.S. Environmental Protection Agency. This Project Summary was developed by EPA's Environmental Monitoring and Support Laboratory, Cincinnati, OH, to announce key findings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). Introduction The Environmental Protection Agency's (EPA's) Environmental Monitoring and Support Laboratory (EMSL), Cincinnati, Ohio, has primary responsibility for devel- oping and evaluating monitoring methods for organic pollutants in industrial waste- waters. Method 603, developed by EPA, for wastewater monitoring involves the use of a heated purge-and-trap technique and gas chromatographic (GC) analysis for the determination of acrolein and acrylonitrile. This method validation study was undertaken in response to the experience of various laboratories which suggested that Method 603 was not a reliable analysis method. For example, a previous single laboratory method validation study performed for EPA by another contracting ------- laboratory produced no useful data. In addition, several investigators have quer- ied EPA regarding difficulties with the reproducibilityof thegaschromatography and problems encountered from acetone interference. Thus, development and use of improved chromatographic conditions was a critical first step in this work. In an effort to increase the usefulness and scope of Method 603, Battelle Columbus Laboratories was contracted to conduct research to: (1) recommend modifications to Method 603 for improv- ing the GC analysis; (2) evaluate the feasibility of including acetonitrile as a method parameter; and (3) validate the method, as modified, using three matrices (reagent water, POTW wastewater and a relevant industrial wastewater) and two spiking levels ([a "low" level near the method detection limit [MDL] and a "high" level at least 10-fold higher than the "low" level]). Analytical Method Evaluation GC Column Evaluations Since acetonitrile was to be included in the parameter list of Method 603, the identification of a suitable GC column for the separation of all three compounds, acetonitrile, acrolein, and acrylonitrile, was a necessary first step. The separation of methylene chloride and acetone from the method parameters was also a con- sideration in selecting the column to be used for validation. Both of the columns specified in the 1982 revision of Method 603 were de- ter mined to be unacceptable. Chromosorb 101 resulted in exact coelution of acrolein and acetonitrile and partial resolution of acetone from acrylonitrile but otherwise it performs adequately for acrolein and acrylonitrile in the absence of acetonitrile. Durapack CW400/Porasil C resulted in coelution of acetone and acrolein and such severe peak tailing that low level injections (100 ng) did not provide usable data. Other column packings were tried, and the results obtained were as follows: (1) 1 percent SP-1000/Carbopack B (moderate tailing and acrolein-acetone coelution); (2) 0.1 percent CW400/Car- bopack C (inadequate retention and severe peak tailing); and (3) Chromosorb 104 (high temperature of elution, unac- ceptable isothermal elution time for acetonitrile and moderate tailing). The column packing used in this work (Porapak QS) was the only one tested that provided good GC peak shape at low levels and baseline separation between the method analytes as well as two potential inter- ferences of interest to EPA (acetone, which elutes between acrolein and acryl- onitrile, and methylene chloride, which elutes between methanol and acetoni- trile). Purge-and-Trap Conditions The purge-and-trap conditions for this validation effort included an 85°C purge with helium at 20 mL/minute flow rate for 15 minutes, a 1.5 minute desorption at 180°C, and a 210°C trap bake for 10 minutes. These conditions were recom- mended by EMSL staff, and were compared to the original Method 603 conditions. In summary, the conditions gave improved peak heights for acetonitrile and acrolein and better reproducibility, due, apparently, to the more rapid delivery of trapped analytes to the GC column and the resulting production of narrower and taller GC peaks. Actual recoveries, how- ever, were about the same for the two conditions. The trap bake temperature of 210°C was employed, since it is generally desirable that the trap bake temperature be higher than the desorption tempera- ture. The low (100°C) desorption tem- perature specified in the 1982 version of Method 603 was required by the initial GC column temperature of 45°C and the sensitivity of Durapak CW400/Porasil C to the presence of liquid water on the column, which would be caused by rapid trap heating to 180°C. For the Porapak QS column packing, problems caused by liquid water are of no concern, since the initial column temperature is 110°C. Moreover, macroreticular phases are generally not susceptible to water dam- age. Method Validation Validation consisted of the analysis of seven replicates at two spiking levels for each of three matrices: reagent water, Columbus POTW secondary effluent, and industrial wastewater from the outfall of a manufacturing plant producing two of the analytes. The water samples were buffered before spiking at pH 4.5 ±0.2 by the addition of sodium citrate to approxi- mately 0.1 m/W and pH adjustment using a glass electrode pH meter. Spiked samples were allowed to equilibrate overnight at ice temperature before analysis on the following day. A summary of the results for the method validation using reagent water, Columbus POTW effluent, and the industrial waste- water are presented in Tables 1,2, and 3, respectively. All quantifications were performed using both external standard calibration and internal standard (IS) calibration with 1 -chloropropane, but only the external standard results are pre- sented in the tables. In general, no significant differences were observed in the results for the two methods of quanti- fication. Acceptable recoveries and pre- cisions were obtained for all method parameters at both spiking levels in the reagent water and Columbus POTW effluents. For the industrial wastewater, acrolein apparently decomposed or was biodegraded despite pH adjustment to a value of 4.5 prior to spiking, and the recoveries for this matrix were less than 12 percent for all replicates analyzed. With the results for reagent water spiked at the lower level, MDLs of 2.7, 0.7, and 0.5 were calculated for aceto- nitrile, acrolein, and acrylonitrile, respec- tively. Summary and Conclusions The validation data collected in this research support the usefulness of Method 603 for the analysis of acetoni- trile, acrolein, and acrylonitrile using the newly established chromatographic con- ditions. The following conclusions can be drawn: • Both of the previously recommended GC columns are unsuitable for the separations needed if acetonitrile is to be included as a method parameter. A Porapak QS column provides the re- quired separation of all three analytes. • The method appears to be precise and accurate for acetonitrile determination even though the purging efficiency of acetonitrile is only about 50 percent. • No apparent advantage is gained by the use of an internal standard calibra- tion procedure. However, the quality assurance feature of an internal standard may have merit in some cases. • Factors that affect acrolein stability in aqueous samples are still not well understood. ------- Table 1. Method Parameter Acetonitrile Acrolein Acrylonitrile Method Validation Result* for Reagent Water Using Modified Method 603 Low Level Spike Results Background Level, fjg/L 0.9 0.0 1.1 Level Spiked, M9/L 10.0 5.0 5.0 Average Recovery, W/L 9.5 5.2 5.3 SD1 0.8 0.2 0.1 RSD,2 % 9 4 3 Average Percent Recovery 86 104 84 Background Level, fjg/L 1.3 0.2 1.0 High Level Spike Results Level Spiked, pg/L 100.0 50.0 50.0 A verage Recovery, fjg/L 112 51.6 524 RSD, SD % 12 11 0.7 1 4 1.5 3 A verage Percent Recovery 111 103 103 ^Standard Deviation. 'Percent Relative Standard Deviation. Table 2. Method Validation Results for Columbus POTW Secondary Effluent Using Modified Method 603 Low Level Spike Results High Level Spike Results Method Parameter Acetonitrile Acrolein Acrylonitrile Background Level, fig/L 0.3 0.2 0.9 Level Spiked, ng/L 10.0 5.0 20.0 Average Recovery, fg/L 10.4 4.2 21.0 SD1 1.5 0.2 0.8 RSD,2 % 14 4 4 Average Percent Recovery 101 80 100 Background Level, fig/L 0.3 0.2 0.9 ^Standard Deviation. 'Percent Relative Standard Deviation. Table 3. Method Validation Results for Industrial Wastewater Using Modified Method 603 Low Level Spike Results Method Parameter Acetonitrile Acrolein Acrylonitrile Background Level, /jig/L 1.2 0.3 2.1 Level Spiked, ug/L 10.0 5.0 10.0 Average Recovery, V9/L 11.0 0.4 11.2 SD1 0.3 0.1 0.8 RSD.2 % 3 25 8 Average Percent Recovery 98 2 91 Background Level, fjg/L 0.3 0.6 0.8 Level Spiked, fjg/L 100 50 100 Average Recovery, ug/L 98 61 107 RSD. SD % 9 9 1.1 1.8 1.6 1.5 A verage Percent Recovery 98 121 106 High Level Spike Results Level Spiked, W/L 100.0 100.0 100.0 Average Recovery, ng/L 99 9.9 105 RSD. SD % 17 17 1.1 11 3.2 3 A verage Percent Recovery 99 9 104 ^Standard Deviation. 2Percent Relative Standard Deviation. ------- S. V. Lucas, T. F. Cole, A. Riggin, and W. M. Cooke are with Battelle-Columbus Laboratories, Columbus. OH 43201-2693. James E. Longbottom is the EPA Project Officer (see below). The complete report, entitled "Evaluation of EPA Method 603 (Modified)," (Order No. PB85-146 629/AS; Cost: $11.50, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield. VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Environmental Monitoring and Support Laboratory U.S. Environmental Protection Agency Cincinnati, OH 45268 * U.S. GOVERNMENT PRINTING OFFICE; 1985 — 569-016/7907 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 Official Business Penalty for Private Use $300 OCOC329 FS ------- |