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50 KGC NO�TN AMERICA VOLUME 21 NUMBER I JANUARY 3003 - -.041 www.chromarographyon/ine.com Table IV: Instrument calibration and performance data Target Analytes Surrogate Compounds Method Parameter MTBE tert-Butyl Alcohol 2-Propanol Acetone MTBE-d3 tert-Butyl Alcohol-dJo Laboratory X Method detection limit(mg/L) 0.27 0.73 4.57^ 4.25• ND ND Practical quantitation limit(mg/L) 1 4 4 4 1 ND Initial calibration Concentration range(mg/L) 1-200 4-400 4-400 4-400 1-200 Mean relative response factor 0.803 0.023 0.021 0.038 0.74 0.021 RSD (%) 3.4 8.6 4.8 Z2 1.6 2 1 Laboratory Y ... Method detection limit(mg/L) 0.28 5 7.3 5 - NIA' N/A Practical quantitation limit(mg/L) 5 10 20 10 N/A. N/A Initial calibration Concentration range(mg/L)t 0.5-200 10-1000 20-2000 5-200 N/A N/A ._.. Mean relative response factor 1.039 0.023 0.013 0.162 N/A N/A RSD(%) 8.55 11.1 3.47 21.4 N/A N/A Laboratory Z Method detection limit(mg/U 0.24 2 ND 1.7 ND ND Practical quantitation limit(mg/L) 0.5 10 10 10 0.5 10 Initial calibration Concentration range(mg/Qt 0.5-100 2.5-500 4-240 4-240 0.5-100 2.5-500 Mean relative response factor 0.436 0.0083 0.0059 0.044 0.455 0.0074 RSD(%) 19.1 7.13 0.998§ 19.6 13.2 9.26 •Method detection limits are greater than the practical quantitation limit.Recalculated method detection limits,using lower standards,likely would result in much lower detection limits. t N/A=Not applicable.This laboratory did not use MTBE-d3 and tert-butyl alcohol-dTo as surrogates;instead it used tert-butyl alcohol-dg as an internal standard. tln some instances,the concentration range of the compound of interest in the initial calibration curve was less than the practical quantitation limit reported by the laboratory.The laboratory attempted to quantitate sample in this range but could not reliably meet accuracy and precision requirements for the low standard. Practical quantitation limits therefore were adjusted accordingly. §This value is not an RSD but rather a correlation coefficient for a linear fit with non-zero intercept. cent difference.Recoveries of the daily scan- Our reviews of raw data allowed other outliers reported. The surrogate recoveries, dards ranged from 84%to 125%,with the method quality control checks - instm- RSDS, and relative percent differences greatest variability observed for 2-propanol. ment tuning, internal standards, and reported by laboratory X for the demonstra- As demonstrated by its quamritation lim- method blanks - which indicated that tion site samples were within the program its and calibration curves, this method met method performance criteria were not goals. The number and magnitude of program sensitivity goals. As measured by exceeded. The target analyte identification exceedances was greater for the other labc- RSDs, the triplicate analyses also were also was acceptable for the detections ratories, with the poorest performance within the program precision goal of 25% reported in the demonstration site samples. observed for acetone; laboratory Y reported (see Table I). However, some matrix A retention time difference of approxi- a consistently low bias for this compound, spike-matrix spike duplicate and low-spike mately 0.1 min was observed again for whereas laboratory Z reported high and results exceeded program accuracy and pre- 2-propanol and acetone. erratic recoveries. Overall, laboratory Z's cision goals(see Tables II and III).Acetone Method 524.2 analysis, with its 25-mL was recovered high (145-234%) in four of Overall Evaluation of Results purge volume, produced the greatest varia- the eight matrix spike-matrix spike dupli- Taken as a whole, the triplicate analytical tions in analytical results and data quality Late spikes,and it was undetected in one of results presented in Table I show an accept- for the four target analytes. the low spikes. We also observed erratic able level of intra-and interlabomtory pre- recoveries for the other target analytes;mul- cision for the method applicability study. Conclusions and tiple recoveries were observed both above The differences between the laboratory Recommendations and below the accuracy limits (75-125%) methods did not produce significant biases The results presented in this article appear for each compound. Laboratory Z repotted in the results, although MTBE and test- to be a successful demonstration of method relative percent differences that exceeded butyl alcohol precision (RSD) appeared applicability, which indicates that purge- the precision limit of 25% for tert-butyl slightly more variable for laboratory Z's and-trap GGMS is an acceptable technol- alcohol and acetone in the matrix method in the higher concentration samples ogy for the analysis of MTBE and its oxy- spike-marrix spike duplicates.The recover- (GWT and H-1). genated breakdown products,at least in the ies of MTBE-d3 and tart-butyl alcohol-d1q, Our review of the spike recovery data in matrices of interest for our Superfund Inno- used as surrogate compounds,were outside Tables II and III indicates that laboratory vative Technology Evaluation program of the program accuracy goals in multiple X's method was slightly more successful in treatment technology demonstration. The sample analyses (see Table I). meeting program data quality goals, in laboratories generally were able to meet pro- terms of both the number and magnitude of gram sensitivity requirements and data