Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 1 of 9 Total Dissolved Solids Dried at 180ºC Total Volatile Dissolved Solids at 550 C References: SM 2540 C, Standard Methods for the Examination of Water and Wastewater, APHA-AWWA-WPCF, 20 th Edition (SDWA) and 21 st Edition (CWA). 1. Scope and Application Matrices: This method is suitable for the determination of Total Dissolved Solids (TDS) and Total Volatile Dissolved Solids (TVDS) in potable, surface, and saline waters, as well as domestic and industrial wastewaters. Definitions: Refer to Alpha Analytical Quality Manual. Solids refer to matter suspended or dissolved in water or wastewater. Solids may affect water or effluent quality adversely in a number of ways. Waters with high dissolved solids generally are of inferior palatability and may induce an unfavorable physiological reaction in the transient consumer. For these reasons, a limit of 500mg dissolved solids/l is desirable for drinking waters. Highly mineralized waters also are unsuitable for many industrial applications. Waters high in suspended solids may be esthetically unsatisfactory for such purposes as bathing. Solids analyses are important in the control of biological and physical wastewater treatment processes and for assessing compliance with regulatory agency wastewater effluent limitations. Total solids is the term applied to the material residue left in the vessel after evaporation of a sample and its subsequent drying in an oven at a defined temperature. Total solids include total suspended solids, the portion of total solids retained by a filter, and total dissolved solids, the portion that passes through the filter. Fixed solids is the term applied to the residue of total, suspended, or dissolved solids after heating to dryness for a specified time at a specified temperature. The weight loss on ignition is called volatile solids. Determinations of fixed and volatile solids do not distinguish precisely between inorganic and organic matter because the loss on ignition is not confined to organic matter. It includes losses due to decomposition or volatilization of some mineral salts The data report packages present the documentation of any method modification related to the samples tested. Depending upon the nature of the modification and the extent of intended use, the laboratory may be required to demonstrate that the modifications will produce equivalent results for the matrix. Approval of all method modifications is by one or more of the following laboratory personnel before performing the modification: Area Supervisor, Department Supervisor, Laboratory Director, or Quality Assurance Officer. This method is restricted to use by or under the supervision of trained analysts. Each analyst must demonstrate the ability to generate acceptable results with this method by performing an initial demonstration of capability and completing the record of training. After initial demonstration, ongoing demonstration is based on acceptable laboratory performance of at least a quarterly laboratory control sample or acceptable performance from an annual proficiency test sample. A major modification to this procedure requires demonstration of performance. The identification of major method modification requiring performance demonstration is directed by the Quality Assurance Officer and/or Laboratory Director on a case-by-case basis.
Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 2 of 9 2. Summary of Method A well-mixed sample is filtered through a standard glass fiber filter, and the filtrate is evaporated to dryness in a weighed dish and dried to constant weight at 180ºC. The increase in dish weight represents the total dissolved solids. The filtrate from the total suspended solids determination (refer to SOP/07-29) may be used for determination of total dissolved solids. Samples submitted for Total Volatile Dissolved Solids analysis are also dried at a higher temperature to a constant weight. 2.1 Method Modifications from Reference None. 3. Reporting Limits The RDL is 10mg/L using a 100mL sample and analytical balance sensitive to 0.1mg, with an upper limit of 2000mg/L. A lower RDL may be achieved by using a larger sample (repeated evaporation of 100mL aliquots) or the use of a more sensitive balance. 4. Interferences 4.1 Highly mineralized water with a significant concentration of calcium, magnesium, chloride, and/or sulfate may be hygroscopic and require prolonged drying, proper desiccation and rapid weighing. 4.2 Samples high in bicarbonate require careful and possibly prolonged drying at 180ºC to ensure complete conversion of bicarbonate to carbonate. 4.3 Exclude large, floating particles or submerged agglomerates of non-homogeneous materials from the sample if it is determined that their inclusion is not desired in the final result. 4.4 Disperse visible floating oil and grease with a blender before withdrawing a sample portion for analysis. 4.5 Because excessive residue in the dish may form a water-trapping crust, limit sample to no more than 200mg residue. 4.5.1 For samples high in dissolved solids, thoroughly wash the filter to ensure removal of dissolved material. Mix small samples with a magnetic stirrer. If suspended solids are present, pipet with wide-bore pipets. If part of a sample adheres to the sample container, consider this in evaluating and reporting results. Some samples dry with the formation of a crust that prevents water evaporating; special handling is required. Avoid using a magnetic stirrer with samples containing magnetic particles. 4.5.2 Prolonged filtration times resulting from filter clogging may produce high results owing to increased colloidal materials captured on the clogged filter.
Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 3 of 9 5. Health and Safety The toxicity or carcinogenicity of each reagent and standard used in this method is not fully established; however, each chemical compound should be treated as a potential health hazard. From this viewpoint, exposure to these chemicals must be reduced to the lowest possible level by whatever means available. A reference file of material safety data sheets is available to all personnel involved in the chemical analysis. Additional references to laboratory safety are available in the Chemical Hygiene Plan. All personnel handling environmental samples known to contain or to have been in contact with municipal waste must follow safety practices for handling known disease causative agents. 6. Sample Collection, Preservation, Shipping and Handling 6.1 Sample Collection Use resistant-glass or plastic bottles, provided that the material in suspension does not adhere to container walls. Sampling, subsampling, and pipetting two-phase or three-phase samples may introduce serious errors. Make and keep such samples homogeneous during transfer. Use special handling to ensure sample integrity when subsampling. 6.2 Sample Preservation None. 6.3 Sample Shipping No specific requirements. 6.4 Sample Handling Begin analysis as soon as possible because of the impracticality of preserving the sample. Refrigerate sample at 4 ±2 ºC up to the time of analysis to minimize microbiological decomposition of solids. In no case hold sample more than 7 days. Bring samples to room temperature before analysis. 7. Equipment and Supplies 7.1 Glass-Fiber Filter Disks: 47mm diameter, without organic binder, Type A/B, size 1.0um. 7.2 Filtration Apparatus: With a membrane filter funnel. 7.3 Side-arm Flask: Of sufficient capacity for sample size selected. 7.4 Evaporation Dishes: 100mL, porcelain, 90mm diameter. 7.5 Dessicator: With a dessicant containing a color indicator of moisture concentration or an instrumental indicator. 7.6 Drying Oven: 75-80ºC. 7.7 Drying Oven: 180ºC ± 2ºC.
Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 4 of 9 7.8 Analytical Balance: Capable of weighing to 0.1mg. 7.9 Magnetic Stirrer: With TFE stirring bar. 7.10 Wide-bore Pipets. 7.11 Graduated Cylinders: 100mL, plastic or glass. 7.12 Wax Crayon or Sharpie pen 7.13 Muffle Furnace: Capable of 550 C. 8. Reagents and Standards 8.1 Reagent Water: Deionized (DI) water. 8.2 LCS Solution: To a 1L volumetric flask, add 0.5g of K 2 SO 4. Bring to volume with DI water. Transfer the solution to a 1L plastic bottle that is labeled with the contents, preparation date, expiration date, and the initials of the preparer. Solution is stored at room temperature. The LCS Solution is valid for 1 year. 9. Quality Control The laboratory must maintain records to document the quality of data that is generated. Ongoing data quality checks are compared with established performance criteria to determine if the results of analyses meet the performance characteristics of the method. 9.1 Blank Filter one blank of DI water per batch of 20 samples or less. Results must be less than the Reporting Limit (RL). If Blank results are less than 10 times the RL and the sample results are greater than 10 times the RL, the data is reported. If Blank results are greater than 10 times the RL, and there is sufficient sample volume remaining, the entire batch is reset and reanalyzed. A narrative is included with the report. 9.2 Laboratory Control Sample (LCS) Filter one LCS per batch of 20 samples or less. Results must be within ± 20% of the true value. If acceptance criteria are not met then the entire sample batch must be reset. If there is insufficient sample volume remaining, the data is submitted and a narrative is included with the final report. 9.3 Initial Calibration Verification (ICV) 9.4 Continuing Calibration Verification (CCV) 9.5 Matrix Spike
Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 5 of 9 9.6 Laboratory Duplicate Filter one duplicate sample per batch of 20 samples or less. Duplicate determinations should have a calculated %RPD < 20%. If acceptance criteria are not met, and there is sufficient sample volume remaining, the sample is reset. Otherwise, the data is submitted and a narrative is included with the final report. 9.7 Method-specific Quality Control Samples None. 9.8 Control Limits The laboratory maintains performance records to document the quality of data that is generated. Method accuracy for samples is assessed and records maintained. The control limits are calculated based on in-house performance data. The limits are compared to the control limits found in the reference method. 9.9 Method Sequence Prepare the evaporation dishes. Weigh the clean evaporation dishes. Filter the appropriate volumes of sample, and QC samples. Rinse the filter with DI water. Transfer the filtrate into a clean, pre-weighed evaporation dish, and rinse the filter flask. Evaporate the filtrate in a 75-80 C oven. Once dry, transfer the dishes into the 180 C oven. Dry for a minimum of 2 hours in a 180 C oven. Cool in a dessicator until temperature is constant. Weigh the dishes until the weight change is less than 4% of the previous weight or 0.5mg, whichever is less. Total Volatile Suspended Solids are also dried for a minimum of 2 hours in a 550 C muffle furnace. Cool in a dessicator until temperature is constant. Weigh the dishes until the weight change is less than 4% of the previous weight or 0.5mg, whichever is less. Calculate results.
Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 6 of 9 10. Procedure 10.1 Equipment Set-up 10.1.1 Preparation of Evaporation Dishes 10.1.1.1 Label evaporating dishes with a unique ID using a wax crayon or Sharpie pen. 10.1.1.2 Bake clean evaporating dishes to 180 ± 2ºC for at least two hours in an oven, but preferably overnight for the greatest stability. 10.1.1.3 Store the evaporation dishes in a dessicator until needed. 10.2 Initial Calibration 10.3 Equipment Operation and Sample Processing 10.3.1 Filtration 10.3.1.1 Remove the evaporating dishes from the dessicator and weigh them immediately before use. Record the weight on the computer worksheet. Also record the date/time/analyst s initials for the analysis on the Excel sheet in the required areas. 10.3.1.2 Insert a glass-fiber filter disk (Section 7.1) with wrinkled side up in the filtration apparatus. Attach a side-arm flask. Note: Record the manufacturer and lot number of the filter used in the logbook. 10.3.1.3 Apply vacuum, and wash the disk with three successive 20mL portions of DI water. 10.3.1.4 Continue suction to remove all traces of water, and discard washings. 10.3.1.5 Selection of Sample Size: Choose a sample volume to yield 200mg dried residue. Generally a 100mL sample volume is used. When very low dissolved solids are encountered (less than 100mg/L), less dried residue may be collected. Compensate for this by using a high-sensitivity balance (0.001mg) or by increasing the amount of sample volume. 10.3.1.6 Samples 10.3.1.6.1 Apply vacuum. 10.3.1.6.2 Pour 100mL of sample (or selected sample volume, Section 10.3.1.5) into a clean 100mL graduated cylinder. Pour this volume into the filtering apparatus. 10.3.1.6.3 If the sample contains sediment, oil, or any other substance, stir the sample using a magnetic stirrer, and while stirring, pipet a measured volume onto the seated filter. 10.3.1.7 Quality Control Samples 10.3.1.7.1 LCS Using a 100mL graduated cylinder, measure 50mL of the LCS Solution (Section 8.2) and pour into the filtering apparatus.
Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 7 of 9 10.3.1.7.2 Blank Using a 100mL graduated cylinder, measure 100mL of DI water and pour into the filtering apparatus. 10.3.1.8 Rinse the filter with three successive 10mL volumes of DI water, allowing complete drainage between washings, and continue suction for about 3 minutes after filtration is complete. 10.3.1.9 Transfer the total filtrate (with washings) to a weighed evaporating dish and evaporate to dryness in an oven at 75-80ºC. Record the date, time in, and the oven temperature in the laboratory notebook. 10.3.1.10 Then, transfer the samples to dry for at least two hours in an oven at 180 ±2ºC. Following removal from the drying oven (Section 10.3.1.9), record the date, time out, and the oven temperature in the laboratory notebook. Following the placement of the samples and QC samples in the 180 ±2ºC oven (Section 10.3.1.10), record the date, time in, and the oven temperature in the laboratory notebook. 10.3.1.11 Remove the dishes from the oven and cool them in a dessicator to constant temperature. Record the date, time out, and the oven temperature in the laboratory notebook. 10.3.1.12 Record the weight of the dishes on the computer worksheet. 10.3.1.13 Repeat drying cycle of drying, cooling, desiccating, and weighing until a constant weight is obtained or until the weight change is less than 4% of the previous weight or 0.5mg, whichever is less. 10.3.1.14 Total Volatile Dissolved Solids 10.3.1.14.1 If TVDS analysis is requested, transfer the crucible to a muffle furnace at 550 C. Record the date, time in, and the oven temperature in the laboratory notebook. 10.3.1.14.2 Dry the crucible for a minimum of 2 hours at 550 C and cool in a dessicator to a constant room temperature. Following placement of the samples and QC samples in the furnace, record the date, time in, and the furnace temperature in the laboratory notebook. Following the placement of the samples and QC samples in the dessicator, record the date, time out, and the furnace temperature in the laboratory notebook. 10.3.1.14.3 Using an analytical balance, weigh the crucible and record the weight on the computer worksheet. 10.3.1.14.4 Repeat the cycle of drying, cooling, dessicating and weighing until a constant weight is obtained or until the weight change is less than 4% of the previous weight, or 0.5mg, whichever is less. Record each weight on the computer worksheet. 10.4 Continuing Calibration
Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 8 of 9 10.5 Preventive Maintenance 10.5.1 Prior to each use, the filtering apparatus is rinsed thoroughly with DI water. 10.5.2 As needed, the filtering apparatus is washed in the industrial dishwasher. 10.5.3 As necessary, wipe the inside of the filtering apparatus with a paper towel and then rinse thoroughly with DI water 10.5.4 Ensure that there is an adequate supply of oil in the vacuum pump 10.5.5 The temperature of the laboratory ovens is recorded constantly on a circular chart recorder. 10.5.6 The chart recorder and the laboratory ovens are calibrated on an annual basis by an instrument service company. Certificates are kept on file in the QA Department. 11. Calculations mg TDS/L = (A B) x 1000 sample volume, (L) where: A = Final weight (weight of dish + dried residue, g) B = Initial weight (weight of clean dish, g) mg TVDS / L = (G N) x 1000 sample volume, (L) where: G = Final Weight at 105 C (weight of dish + dried residue, g) N = Weight at 550 C (weight of dish + dried residue, g) 12. Contingencies for Handling Out-of-Control Data or Unacceptable Data Holding time exceedence and improper preservation are noted on the nonconformance report form. Perform routine preventative maintenance as outlined in Section 9.3. Review of blanks and LCS for acceptable performance occurs for each batch of samples. Record any trends or unusual performance on a nonconformance action form. If the LCS recovery falls outside the designated acceptance range, the laboratory performance is judged to be out of control, and the problem must be immediately identified and corrected. The analytical result is suspect and is only reported for regulatory compliance purposes with the appropriate nonconformance action form. Immediate corrective action includes reanalyzing all affected samples by using any retained sample before the expiration of the holding time.
Title: Total Dissolved Solids Dried at 180ºC and Total Volatile Dissolved Solids at 500 C Page 9 of 9 13. Method Performance 13.1 Method Detection Limit Study (MDL) / Limit of Detection Study (LOD) / Limit of Quantitation (LOQ) The laboratory follows the procedure to determine the MDL, LOD, and/or LOQ as outlined in Alpha SOP/1732. These studies performed by the laboratory are maintained on file for review. 13.2 Demonstration of Capability Studies Refer to Alpha SOP/1734 and 1739 for further information regarding IDC/DOC Generation. 13.2.1 Initial (IDC) The analyst must make an initial, one-time, demonstration of the ability to generate acceptable accuracy and precision with this method, prior to the processing of any samples. 13.2.2 Continuing (DOC) The analyst must make a continuing, annual, demonstration of the ability to generate acceptable accuracy and precision with this method. 14. Pollution Prevention and Waste Management Refer to Alpha s Chemical Hygiene Plan and Waste Management and Disposal SOP for further pollution prevention and waste management information. 15. Referenced Documents Chemical Hygiene Plan SOP/1732 MDL/LOD/LOQ Generation SOP/1734, 1739 IDC/DOC Generation SOP/1728 Waste Management and Disposal SOP 16. Attachments None.