Mar 24, 2023
Water sample collection and processing
This protocol is a draft, published without a DOI.
- 1Northwest Irrigation and Soil Research Laboratory, USDA-ARS, Kimberly, ID
Protocol Citation: isis.scott 2023. Water sample collection and processing. protocols.io https://protocols.io/view/water-sample-collection-and-processing-cgcstswe
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: September 08, 2022
Last Modified: March 24, 2023
Protocol Integer ID: 69746
Abstract
This protocol includes the guidelines for water sample collection and processing (CEAP samples)
Materials
15-mL centrifuge tubes, polypropylene, conical bottom w/ CentriStar cap, sterile, natural;
0.45 µm pore size, hydrophilic PVDF membrane filter;
30-mL sterile syringes;
0.45 µm syringe filters;
60-mL Nalgene Square wide-mouth HDPE bottles;
2-L HDPE bottles;
Sampling pole;
Disposable covered 50 mm petri dishes
Magnetic stirring bar
250-mL volumetric flask
Turkey baster
Filtration manifold
Magnetic cylinders
SCOPE
SCOPE
This standard operating procedure (SOP) describes the procedure for the collection and processing of water samples in the Snake River Basin. Water samples are collected often for assessing water quality in the irrigation return flows to the Snake River. The samples are analyzed for pH, electrical conductivity (EC), total suspended solids (TSS), total Kjeldahl nitrogen (N), FIA-analyzed nitrate, ammonia and chloride, and digested for ICP analysis of Al, Ca, Fe, K, Mg, Na, P, S, and Zn.
Preparing for sample collection
Preparing for sample collection
1h
1h
Labelling bottles:
Label 2-L bottles and 60-mL bottles with sample location and sample number
Label 15-mL centrifuge tubes with the sample location, sample number ,date and initials.
Pipette 150 µL of 1 Molarity (M) or 6.2 mg/mL boric acid solution into centrifuge tubes
Petri dishes and filter membranes:
Equipment
OHAUS™ Explorer™ Semi-Micro Balance or equivalent
NAME
Semi-Micro Balance
TYPE
Ohaus
BRAND
01-919-370
SKU
LINK
0.01 mg to 52 gm capacity
SPECIFICATIONS
Equipment
Oven
NAME
Oven forced-air convection
TYPE
Fisher Isotemp
BRAND
15-103-0510
SKU
LINK
Equipment
Vacuum Desiccator
NAME
Ted Pella
BRAND
2246
SKU
LINK
Any vacuum desiccator that will fit your samples will work
SPECIFICATIONS
Lay out petri dishes and add one membrane filter to each dish. Place then
in the oven at 60 °C Overnight
Place petri dishes in the desiccator. Apply vacuum until it stops hissing, and disconnect vacuum tubing. Turn the valve to maintain vacuum. Keep the dishes in the desiccator for 01:00:00 .
1h
Weigh petri dishes + filter. Record weights in the worksheet.
Sample processing: filtering for FIA analysis
Sample processing: filtering for FIA analysis
Sample filtering will depend on the number of sampling locations to be visited. If samples are collecting in one location only (e.g., water quality ponds), samples are to be filtered on site. If more sampling locations are to be visited (e.g. CEAP samples), all 2-L samples are brought into the lab and filtering will occur on the day or day after of collection. Unfiltered samples need to be stored in walk-in cooler if not filtered on the same day of collection. The steps for filtering are described below:
Transfer a 15-mL aliquot of water sample from the 2-L bottle using a syringe.
Attach a 0.45 µm syringe filter and filter the water into a 15-mL centrifuge tube containing boric acid.
Filtered samples are to be stored in the refrigerator in Room 119 until analysis.
Sample processing: unfiltered samples
Sample processing: unfiltered samples
Transfer a 50-mL aliquot of water sample from the 2-L bottle to the 50-mL bottles and store them in the refrigerator in Room 119 until TKN analysis. This step can also be conducted during the TSS analysis, if preferred.
Sample processing: pH end EC measurements
Sample processing: pH end EC measurements
When 2-L water samples are at room temperature, measure pH and EC using the pH and EC meters in the Annex.
pH and EC meters must be calibrated before measuring. For EC, use 84 and 1413 µS/cm calibrators. For pH, use the 7 and 10 calibrators.
Sample processing: TSS analysis
Sample processing: TSS analysis
Place blank 0.45 µm membrane filters on each of the cylinder attachments on the filtration manifold using tweezers. Cover with the plastic cylinders.
Place water sample on stirrer and stir until vortex is formed and the sediment is in suspension.
Collect a 150 mL aliquot using the turkey baster into the volumetric flask and transfer it to the vacuum cylinder. The final amount of water that is filtered for TSS determination will depend on the amount of sediment in the sample. I there's little sediment, the volume filtered should be increased (i.e., if the volume added of water sample is filtered in less than ~2 minutes, add another 150 mL of sample to cylinder). For high-sediment samples, the volume to be filtered will need to be reduced to 50 mL or 100 mL .
Rinse the graduated cylinder with DI water and add that volume to the vacuum cylinder to account for the residual sediment.
Apply vacuum to manifold by opening the valves for the cylinders being used.
Once sample filtering is complete, remove the cylinders, and place the membrane filters back onto the Petri dishes using the tweezers.
Rinse cylinders, turkey baster, magnetic stirrer, and volumetric flask before moving to the next sample.