THE ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM SEPA Battelie . iechnobgy to ETV Joint Verification Statement TECHNOLOGY TYPE: ARSENIC TEST KIT APPLICATION: ANALYSIS OF ARSENIC IN WATER TECHNOLOGY NAME: Quick™ Low Range II COMPANY: Industrial Test Systems, Inc. ADDRESS: 1875 Langston Street PHONE: (803) 329-9712 Rock Hill, SC 29730 FAX: (803) 329-9743 WEB SITE: www.sensafe.com E-MAIL: its@cetlink.net The U.S. Environmental Protection Agency (EPA) supports the Environmental Technology Verification (ETV) Program to facilitate the deployment of innovative or improved environmental technologies through performance verification and dissemination of information. The goal of the ETV Program is to further environmental protection by substantially accelerating the acceptance and use of improved and cost-effective technologies. ETV seeks to achieve this goal by providing high-quality, peer-reviewed data on technology performance to those involved in the design, distribution, financing, permitting, purchase, and use of environmental technologies. ETV works in partnership with recognized standards and testing organizations; with stakeholder groups that consist of buyers, vendor organizations, and permitters; and with the full participation of individual technology developers. The program evaluates the performance of innovative technologies by developing test plans that are responsive to the needs of stakeholders, conducting field or laboratory tests (as appropriate), collecting and analyzing data, and preparing peer-reviewed reports. All evaluations are conducted in accordance with rigorous quality assurance (QA) protocols to ensure that data of known and adequate quality are generated and that the results are defensible. The Advanced Monitoring Systems (AMS) Center, one of seven technology areas under ETV, is operated by Battelie in cooperation with EPA's National Exposure Research Laboratory. The AMS Center has recently evaluated the performance of portable analyzers for arsenic in water. This verification statement provides a summary of the test results for the Industrial Test Systems, Inc. Quick™ Low Range II test kit for measuring arsenic in water. ------- VERIFICATION TEST DESCRIPTION The Quick™ Low Range II test kit is an inexpensive, portable, rapid device designed for on-site analysis of arsenic in water. The Quick™ Low Range II test kit was verified in terms of its performance on the following parameters: accuracy, precision, linearity, method detection limit (MDL), matrix interference effects, operator bias, inter-unit reproducibility, and rate of false positives/false negatives. Results for two additional detection devices, the Quick™ Arsenic Scan and Compu-Scan, also were reported. All preparation and analyses were performed according to the manufacturer's recommended procedures. Results from the Quick™ Low Range II test kit were compared to those from the reference method to assess accuracy, linearity, and detection limit. Multiple aliquots of performance test samples and environmental samples were analyzed to assess precision. Matrix interference effects were assessed by challenging the test kit with performance test samples of known arsenic concentrations containing both low-level and high-level interferences. Identical sets of samples were analyzed independently by two separate operators (a technical and a non-technical Battelle staff member) to evaluate operator bias. All samples were analyzed using two Quick™ Arsenic Scan and Compu-Scan units to evaluate inter-unit reproducibility. False positives and negatives were evaluated relative to the 10-ppb maximum contaminant level for arsenic in drinking water. In addition to the analytical results, the time required for sample analysis and operator observations concerning the use of the test kit (e.g., frequency of calibration, ease of use, maintenance) were recorded. Three types of samples were used in the verification test: quality control (QC) samples, performance test (PT) samples, and environmental water samples. The QC and PT samples were prepared from National Institute of Standards and Technology traceable purchased standards. The environmental water samples were collected from various drinking water and surface water sources. All samples were analyzed using the Quick™ Low Range II test kits and by a laboratory reference method. QA oversight of verification testing was provided by Battelle. Battelle QA staff conducted a data quality audit of 10% of the test data, a performance evaluation audit, and a technical systems audit of the procedures used in this verification. TECHNOLOGY DESCRIPTION The optimal detection range for the Quick™ Low Range II test kit is below 15 ppb arsenic. Dilution instructions are provided for samples with arsenic levels above 8 ppb. The recommended temperature range for sample analysis is 24°C to 30°C. A modified testing protocol is available for sample temperatures below this range. To perform arsenic analyses with the Quick™ Low Range II test kit, the water sample to be tested is mixed in the supplied reaction vessel with reagent #1 (tartaric acid with rate enhancers) to acidify the water sample. Reagent #2, an oxidizer (potassium peroxymonosulfate), is added to remove hydrogen sulfide interference. The test tolerates up to 2 ppm hydrogen sulfide without interference. Zinc powder, reagent #3, is added to reduce inorganic arsenic compounds (As+3 and As+5) to arsine gas. As arsine gas is generated and comes in contact with the test strip, the mercuric bromide indicator on the test strip changes color from white to shades of yellow or brown. Material Safety Data Sheets (MSDS) for all reagents and test strips are provided with each test kit. The MSDSs include information on how to safely handle the reagents and test strips, including instructions for exposure controls and personal protection. Once the reaction is completed, the test strip is removed and visually compared to a color chart to obtain a semi- quantitative measure of the arsenic concentration in the tested sample. The color chart consists of a series of color blocks that correspond to concentrations ranging from 0.6 ppb to >100 ppb. The test strip may also be read with the Quick™ Arsenic Scan hand-held instrument, which operates on the same principle as a colorimeter and provides a quantitative result. The Quick™ Arsenic Scan is calibrated weekly using a calibration card provided by the manufacturer. Quantitative results may also be obtained from the test strip with a portable Compu-Scan scanner and laptop system. The scanned test strip image is converted to an arsenic concentration using the Home Port Computer System Arsenic Program Revision 5b software. The scanner is calibrated by the manufacturer. The Quick™ Arsenic Scan and Compu-Scan are not provided with the Quick™ Low Range II test kit as a standard feature. The standard test kit with the color chart was the subject of this verification test; however, results for the Quick™ Arsenic Scan and Compu-Scan were also provided. The test kits with the color charts are available in ------- sets of 50 tests with test strips provided in individually sealed packets. The typical shelf life of the kits is 24 months. VERIFICATION OF PERFORMANCE Accuracy: The bias for the Quick™ Low Range II color chart ranged from -92% to -8% for the technical operator and -74% to 74% for the non-technical operator. The bias for the Quick™ Arsenic Scan ranged from - 98% to -27% for the technical operator and -76 to 9% for the non-technical operator. The bias for the Compu- Scan ranged from -93% to 104% for the technical operator and from -67% to 81% for the non-technical operator. The overall agreement for the color chart results based on an assessment of whether the result was assigned to the correct color block indicated that the total percent agreement was 45% for the technical operator and 38% for the non-technical operator. Precision: For the technical operator, relative standard deviations (RSDs) ranged from 0% to 55% for the color chart, 0% to 84% for the Quick™ Arsenic Scan, and 7% to 91% for the Compu-Scan. For the non-technical operator, RSDs ranged from 0% to 15% for the color chart, from 9% to 67% for the Quick™ Arsenic Scan, and from 14% to 55% for the Compu-Scan. These results exclude samples where one or more of the replicate results was not detected by the Quick™ Low Range II test kit. Linearity: The linearity of response was evaluated by plotting the test kit results against the reference analysis results for the PT samples. The equations for the linear regressions that were performed to evaluate linearity are as follows, where x is the reference method concentration and y is the test kit concentration: Method Detection Limit: The MDL was assessed by analyzing seven replicates of a sample spiked at a level approximately five times the manufacturer's estimated detection limit for the color chart. The MDLs calculated using the precision data from these replicates ranged from 1.2 ppb to 1.5 ppb for the color chart, from 0.7 ppb to 2.1 ppb for the Quick™ Arsenic Scan, and from 0.5 ppb to 3.9 ppb for the Compu-Scan. Matrix Interference Effects: Low and high levels of interferents did not appear to affect the detection of arsenic. Biases for these samples were similar to those calculated for PT samples containing arsenic only. Operator Bias: Measurements for the color chart, Quick™ Arsenic Scan, and Compu-Scan done by the non- technical operator tended to be higher than for the technical operator. A paired t-test of the two sets of data indicated that the results were significantly different at a 5% significance level. Inter-Unit Reproducibility: The Quick™ Arsenic Scan results were more reproducible than the Compu-Scan results. Paired t-tests of the two sets of data indicated that the Quick™ Arsenic Scan results were not significantly different at a 5% significance level; however, the Compu-Scan results were significantly different. Rate of F alse Positives/F alse Negatives: The false positive rates for the technical and non-technical operators using the color charts and Quick™ Arsenic Scan units were 0%. The rates of false positives for the Compu-Scan were 0% for both operators, except for Compu-Scan Unit #2, with a false positive rate of 3%. The false negative rates for the technical and non-technical operators using the color charts were 62% and 33%, respectively. The false negative rates for the Quick™ Arsenic Scan units were 62% for the technical operator (Units # 1 and #2) and 38% for the non-technical operator (Unit #1). The false negative rates for the Compu-Scan were 67% and 52% for the technical operator (Units #1 and #2, respectively) and 9.5% for the non-technical operator (Unit #1). Color chart, technical operator Color chart, non-technical operator Quick™ Arsenic Scan #1, technical operator Quick™ Arsenic Scan #2, technical operator Quick™ Arsenic Scan #1, non-technical operator Compu-Scan #1, technical operator Compu-Scan #2, technical operator Compu-Scan #1, non-technical operator y = 0.79x- 0.03, R = 0.9904 >>=0.71x + 7.29, R =0.9038 >>=0.42x + 0.29, R =0.9619 y = 0.40x + 0.19, R =0.9776 y= 0.7lx + 2.45, R =0.9826 y = 0.33x + 1.03, R =0.9043 >>=0.40x + 3.05, R =0.9063 y = 0.67x + 1.39, R =0.9174 ------- Other Factors: The Quick™ Low Range II test kits were easy to use and readily transportable to the field. The sample bottles were of moderate size and were relatively easy to handle. The test kits were reliable. Analysis of diluted samples was sometimes difficult for the non-technical operator. Dilution of samples with arsenic concen- trations exceeding the optimal detection range may be a source of error and reduce the accuracy and precision of the associated results because of the difficulty in performing accurate dilution in a field setting. The time to analyze one sample is approximately 15 minutes at a temperature range of 24°C to 30°C; longer reaction times are required for samples below this range. Two samples can be run concurrently without difficulty. The cost for a 50-sample test kit with a color chart is listed as $349.99. Replacement reagents and supplies are not available; kits are provided as a complete set because reagents, test strips, and color charts are made to perform optimally with each other. The Quick™ Arsenic Scan and Compu-Scan are available as options for an additional cost of $1,599.99 each. signed by Gabor J. Kovacs 8/7/03 signed by Gary J.Folev 9/30/03 Gabor J. Kovacs Date Gary J. Foley Date Vice President Director Environmental Sector National Exposure Research Laboratory Battelle Office of Research and Development U.S. Environmental Protection Agency NOTICE: ETV verifications are based on an evaluation of technology performance under specific, predetermined criteria and the appropriate quality assurance procedures. EPA and Battelle make no expressed or implied warranties as to the performance of the technology and do not certify that a technology will always operate as verified. The end user is solely responsible for complying with any and all applicable federal, state, and local requirements. Mention of commercial product names does not imply endorsement. ------- |