EPA Method 1694

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EPA Method 1694:
Pharmaceuticals and personal care products in water, soil, sediment, and biosolids by HPLC/MS/MS. Official Name: Pharmaceuticals and personal care products in water, soil, sediment, and biosolids by HPLC/MS/MS

Summary:
The pH of a 1-L sample aliquot is adjusted to 2 with acid. The pH of a second 1-L aliquot of sample is adjusted with 10 with base. Stable, isotopically labeled analogs of the analytes of interest are spiked into their respective acid or base fraction. The acid fraction is stabilized with tetrasodium ethylenediamine-tetraacetate dehydrate (NA4EDTA.2H2O.2H2O).Solid and semi-solid samples, including biosolids and visible particles from aqueous samples. A phosphate buffer and an ammonium hydroxide solution are used to adjust the pH, respectively, of up to 1 g each of dry solids from a solid sample, or 1 g each of dry solids filtered from an aqueous sample. The labeled compounds are spiked into their respective acid and base fractions. The acid fraction is ultrasonically extracted three times with a phosphate buffer/acetonitrile solution and the base fraction is ultrasonically extracted three times with a ammonium hydroxide/acetonitrile solution. The solutions are concentrated to remove the acetonitrile and diluted with reagent water. The acid fraction is stabilized with NA4EDTA.2H2O.2H2O.Sample cleanup:The acid and base fraction solutions are separately cleaned up using solid-phase extraction (SPE) with hydrophilic-lipophillic balance (HLB) cartridges. After cleanup, the fractions are exchanged to methanol, labeled injection internal standards are added, and the final volume is adjusted to 4 mL with the LC elution solvent.Determination by LC/MS/MS:The acid extract is analyzed in two positive electrospray ionization (ESI+) LC/MS/MS runs and one negative electrospray ionization (ESI-) run, each specific to a subset of the analytes of interest. The base extract is analyzed in a single ESI+ run. The analytes are separated by the LC and detected by a tandem (1,000 resolution) mass spectrometer. A daughter m/z for each compound is monitored throughout a pre-determined retention time window.An individual compound is identified by comparing the LC retention time and presence of the daughter m/z with the corresponding retention time and daughter m/z of an authentic standard.Quantitative analysis is performed in one of two ways, using selected ion current profile (SICP) areas:1) For a compound for which a labeled analog is available, the concentration is determined using the isotope dilution technique and a multipoint calibration of all the target analytes. Isotope dilution provides automatic correction of the target analyte concentrations.2) For a compound for which a labeled analog is not available, the concentration is determined using the internal standard technique and a multipoint calibration of all the target analytes. The labeled compounds are used to recovery correct results of those analytes quantitated by the internal standard technique.3) Additional labeled compounds may be incorporated into this method, at the user's discretion to determine the concentration of the native compound using the isotope dilution technique provided that all performance requirements in this method are met.The quality of the analysis is assured through reproducible calibration and testing of the extraction, cleanup, and LC/MS/MS systems.NOTE:Some of the compounds in this method are controlled substances. Laboratories performing this method should have all appropriate licenses and certifications and obtain all needed standards and chemicals from licensed sources. For some of the compounds in this method it may be necessary for laboratories to obtain a DEA license.

Scope:
This method is for determination of pharmaceuticals and personal care products (PPCPs) in multi-media environmental samples by high performance liquid chromatography combined with tandem mass spectrometry (HPLC/MS/MS).

Citation:
U.S. Environmental Protection Agency, 2007, Method 1694: Pharmaceuticals and personal care products in water, soil, sediment, and biosolids by HPLC/MS/MS: USEPA, Washington, DC, EPA-821-R-08-008, 77 p.

Interferences:
Solvents, reagents, glassware, and other sample processing hardware may yield artifacts, elevated baselines, matrix enhancement or matrix suppression causing misinterpretation of chromatograms. Specific selection of reagents and purification of solvents by distillation in all-glass systems may be required. Where possible, reagents are cleaned by extraction or solvent rinse.Proper cleaning of glassware is extremely important, because glassware may not only contaminate the samples but may also remove the analytes of interest by adsorption on the glass surface. All materials used in the analysis must be demonstrated to be free from interferences by running reference matrix method blanks initially and with each sample batch.Interferences co-extracted from samples will vary considerably from source to source, depending on the diversity of the site being sampled. Interfering compounds may be present at concentrations several orders of magnitude higher than the analytes of interest. Because low levels of PPCPs are measured by this method, elimination of interferences is essential. Cleanup steps given in the method report can be used to reduce or eliminate these interferences and thereby permit reliable determination of the PPCPs at the levels described.It may be useful to number reusable glassware in order to associate glassware with the processing of a particular sample. This will assist the laboratory in tracking possible sources of contamination for individual samples, identifying glassware associated with highly contaminated samples that may require extra cleaning, and determining when glassware should be discarded.Contamination from personal care products used by laboratory staff that are also target analytes is possible. Target analytes also include commonly used medications. Therefore, it is important to take precautions to avoid contamination of the samples, for example wearing of protective gloves and clothing.

QC Requirements:
Each laboratory that uses this method is required to operate a formal quality assurance program. The minimum requirements of this program consist of an initial demonstration of laboratory capability, analysis of samples spiked with labeled compounds to evaluate and document data quality, and analysis of standards and blanks as tests of continued performance. Laboratory performance is compared to established performance criteria to determine if the results of analyses meet the performance characteristics of the method.

Maximum Holding Time:
Extract within 48 hours of collection and analyze extract within 40 days. Freeze sample to minimize degradation and increase holding time to 7 days; if frozen, extract within 48 hours of removal from freezer.

Media:
VARIOUS

Subcategory:
Organic

Concentration:
Variable based on analyte and media

Sample Prep:
See the method report for sample preparation information.

Precision:
The accuracy and precision were determined after analysis of 5 samples in reagent water at a single laboratory.Performance data was reported for all analytes except for ampicillin and erythromycin.

Detection:
The detection limits in this method are usually dependent on the level of interferences rather than instrumental limitations and were determined using methods described in 40 CFR 136, appendix B. The detection limits presented are those that can be determined in the absence of interferences.MDLs were reported for all analytes, except for ampicillin, erythromycin, and digoxin, for which minimum levels of quantiation (MLs) were reported.

Revision Number:
7-Dec