Since the method states "less than a pH of 2" most of our collectors overkill on the HCl. We adjust the QC to match the samples which are always more like than 2. That could be the problem. I am having a little less recovery with the other PAHs, but Anthracene is definately being oxidized because I can see the anthraquinone on the MS. My dperylene along with the benzo a pyrene is also a major problem. Please add to the discussion any other ideas you may have.
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Munch and Paul E. Grimmett U. Munch and Steven C. Wendelken U. Zaffiro and Michael L. Zimmerman Shaw Environmental and Infrastructure, Inc. Accu- racy and precision data have been generated in reagent water, and in finished ground and surface waters for the compounds listed in the table below. SIM is useful when enhanced sensitivity is desirable. An example chromatogram which includes the entire analyte list is shown in Figs, la-Id. The LCMRL is compound dependent and is also dependent on extraction efficiency, sample matrix, fortification concentration, and instrument performance.
DLs have been determined for all analytes in two laboratories in full It is highly recommended that analysts and laboratory managers consider analyzing a subset of the analyte list that will meet their data collection needs.
Over individual congeners, mainly chlorinated bornanes, have been identified in the technical mixture, although over 30, are theoretically possible. Using the instrument parameters in Method Therefore, all calibration standards and quality control procedures for toxaphene must be prepared and analyzed in separate samples from all the other method analytes. Toxaphene may be analyzed using this method in either full scan or SIM mode. However, the authors have demonstrated the method in SIM mode only.
At the time of method development, the enhanced sensitivity provided by SIM was necessary to meet the drinking water monitoring trigger of 0. Detailed instructions for the identification and quantitation of toxaphene are in Sect. This method is designed for Aroclor screening only and not for qualitative or quantitative analyses of specific Aroclors.
It contains at least chlorinated components. At the concentrations likely to be encountered in drinking water samples, only two or three major components will typically be identified: cis- and These major components are listed as method analytes along with technical chlordane. Specific instructions for quantification of technical chlordane are provided in Sect.
Changes may not be made to sample collection and preservation Sect. Method modifications should be considered only to improve method performance. Modifications that are introduced in the interest of reducing cost or sample processing time, but result in poorer method performance, should not be used. In all cases where method modifications are proposed, the analyst must perform the procedures outlined in the initial demonstration of capability IDC, Sect. Note: The above method flexibility section is intended as an abbreviated summation of method flexibility.
If there is any perceived conflict between the general method flexibility statement in Sect. A 1-liter water sample is fortified with surrogate analytes and passed through a solid phase extraction SPE device Sects.
The compounds are eluted from the solid phase with a small amount of two or more organic solvents. The solvent extract is dried by passing it through a column of anhydrous sodium sulfate, concentrated by evaporation with nitrogen gas, and then adjusted to a 1-mL volume with ethyl acetate after adding the internal standards. A splitless injection is made into a GC equipped with a high-resolution fused silica capillary column that is interfaced to an MS. The concentration of each analyte is calculated by using its integrated peak area and the internal standard technique.
Surrogate analytes are added to all Field and Quality Control QC Samples to monitor the performance of each extraction and overall method performance. Refer to The CAL solutions are used to calibrate the instrument response with respect to analyte concentration. In this method, traditional CAL standards prepared in ethyl acetate may be used or matrix-matched standards Sect. This procedure is described in Sect.
This is a statistical determination Sect. Analyses of FD1 and FD2 provide an estimate of the precision associated with sample collection, preservation, and storage, as well as with laboratory procedures. In this method, the internal standards are isotopically labeled analogues of selected method analytes. The LFB is processed and analyzed exactly like a sample, and its purpose is to determine whether the methodology is in control, and whether the laboratory is capable of making accurate and precise measurements.
The LFSM is processed and analyzed exactly like a sample, and its purpose is to determine whether the sample matrix contributes bias to the analytical results. The background concentrations of the analytes in the sample matrix must be determined in a separate aliquot and the measured values in the LFSM corrected for background concentrations.
The LFSMD is used instead of the Field Duplicate to assess method precision and accuracy when the occurrence of a method analyte is infrequent. The LRB is used to determine if method analytes or other interferences are present in the laboratory environment, the reagents, or the extraction apparatus. When subsequent sample extracts containing the analytes and components from a complex sample matrix are injected, peak shape and response improve.
In this situation, quantitative data for field samples may exhibit a high bias. The material extracted from the matrix reduces matrix-induced response enhancement effects and improves the quantitative accuracy of sample results.
This concentration must meet the criteria defined in Sect. The MRL may be determined by the laboratory based upon project objectives, or may be set by a regulatory body as part of a compliance monitoring program. The QCS is used to verify the accuracy of the primary calibration standards. When used with gas chromatography, the set of ions monitored is usually changed periodically throughout the chromatographic run, to correlate with the characteristic ions of the analytes, SURs and ISs as they elute from the chromatographic column.
The technique is often used to increase sensitivity. When used with gas chromatography, the set of ions stored is usually changed periodically throughout the chromatographic run, to correlate with the characteristic ions of the analytes, SURs and ISs as they elute from the chromatographic column.
SIS can be used to enhance sensitivity. The purpose of the SUR is to monitor method performance with each sample. All glassware must be meticulously cleaned. Wash glassware with detergent and tap water, rinse with tap water, followed by reagent water. All items such as these must be routinely demonstrated to be free from interferences less than Vs the MRL for each target analyte under the conditions of the analysis by analyzing laboratory reagent blanks as described in Sect.
Subtracting blank values from sample results is not permitted. Matrix interferences may be caused by contaminants that are co-extracted from the sample. The extent of matrix interferences will vary considerably from source to source, depending upon the nature of the water. Water samples high in total organic carbon TOC may have elevated baselines or interfering peaks.
Matrix components may directly interfere by producing a signal at or near the retention time of an analyte peak. They can also enhance the signal of method analytes Sect. Analyses of LFSMs are useful in identifying matrix interferences.
Relatively large quantities of the buffer and preservatives Sect. The potential exists for trace-level organic contaminants in these reagents. Interferences from these sources should be monitored by analysis of laboratory reagent blanks, particularly when new lots of reagents are acquired. Solid phase extraction media have been observed to be a source of interferences. Brands and lots of solid phase extraction devices should be tested to ensure that contamination does not preclude analyte identification and quantitation.
Analyte carryover may occur when a relatively "clean" sample is analyzed immediately after a sample or standard that contains relatively high concentrations of compounds. Syringes and GC injection port liners must be cleaned carefully or replaced as needed. After analysis of a sample or standard that contains high concentrations of compounds, a laboratory reagent blank should be analyzed to Silicone compounds may be leached from punctured autosampler vial septa, particularly when particles of the septa sit in the vial.
This can occur after repeated injections from the same autosampler vial. These silicone compounds, which appear as regularly spaced chromatographic peaks with similar MS fragmentation patterns, can unnecessarily complicate the total ion chromatograms and may cause interferences at high levels.
Quantitation of bromacil should be reviewed for potential common interferences. Laboratories should select the QI depending on the sorbent being used and the amount of bleed associated with the GC column. If both types of interferences are present, some laboratories may not be able to analyze for bromacil at low concentrations.
Manual inspection of all bromacil data reported in field samples is mandatory. There are many potential sources of phthalate contamination in the laboratory, especially from plastics and chemicals that may have been stored in plastic containers. If phthalates are to be reported as method analytes, care must be taken to minimize sources of contamination, and the QC criteria for LRBs must be met Sect. Special precautions must also be taken when creating calibration curves for analytes consistently found in LRBs Sect.
In cases where the SPE disks or cartridges are dried by pulling room air through the media using vacuum, it may be possible for the media to become contaminated by components in room air.
This was not observed during method development. If laboratories encounter contamination problems associated with room air, compressed gas cylinders of high purity nitrogen may be used for drying SPE media during sample processing.
The toxicity or carcinogenicity of each reagent used in this method has not been precisely defined. Each chemical should be treated as a potential health hazard, and exposure to these chemicals should be minimized. Each laboratory is responsible for maintaining an awareness of OSHA regulations regarding safe handling of chemicals used in this method.
A reference file of MSDSs should be made available to all Additional references to laboratory safety are available. Pure standard materials and stock standard solutions of these compounds should be handled with suitable protection to skin and eyes, and care should be taken not to breathe the vapors or ingest the materials.
Other brands of equivalent quality may be used. The SPE sorbents described in Sects. The sorbents described in Sects.
Semivolatiles on Rxi-5ms by EPA Method 525.2
Kelso, Washington Laboratory Method information displayed is provided for informational purposes only. No warranty express or implied is made as to the website accuracy, completeness, or applicability such as the age of a method and whether or not it applies to your project. Please contact us for assistance. Summary: Organic compound analytes, internal standards, and surrogates are extracted from a 1L sample by passing it through a disk or cartridge containing a solid matrix with a chemically bonded C18 organic phase [liquid-solid extraction LSE ]. Organic compounds are extracted from the LSE with small quantities of ethyl acetate followed by methylene chloride with further evaporation of the solvent.
Drinking Water Analysis by EPA 525.2
Munch and Paul E. Grimmett U. Munch and Steven C. Wendelken U. Zaffiro and Michael L. Zimmerman Shaw Environmental and Infrastructure, Inc.