The percent ammonia nitrogen was determined in Passaic River waste water using Ion-Selective Electrode EPA Method 350.3. The intelligent ammonia sensor integrates ammonia electrode, pH electrode and Ammonia Ion electrode together to realize the in situ detection of ammonia. The test results have shown that the sensor is easy operation, low cost and no pollution. The ammonia is determined potentiometrically using an ammonia ion selective electrode and a pH/mV meter, having an expanded millivolt scale. The ammonia selective electrode uses a hydrophobic gas-permeable membrane to separate the sample solution from an electrode internal solution of ammonium chloride. Dissolved ammonia is converted to NH 3 gas by raising the pH to above 11.0 with a strong base. NH 3 gas diffuses the membrane and changes the internal solution pH that is sensed by the electrode. In single laboratory test results have been found 1.001 NH 3-/L and 0.897 mg NH 3-N/L, recoveries were 77.3% and 83.1%, respectively.
The Passaic River is a river, approximately 80 mi (129 km) long [
The river flows northeast into the city of Paterson, where it drops over the Great Falls of the Passaic. On the north end of Paterson, it turns abruptly south, flowing between Paterson and Clifton on the west and Hawthorne, Fair Lawn, Elmwood Park, Garfield on the east, next through the city of Clifton. At Elmwood Park it begins to form Dundee Lake, created by the Dundee Dam built in 1845. The river becomes navigable two and a half miles downstream of the Dundee Dam at the Eighth Street/Locust Ave Bridge in Wallington where the dredged Wallington Reach channel begins [
In its lowest reaches, it flows along the northeast portion of the city of Newark on the west, passing Kearny, East Newark, and Harrison, New Jersey on the eastern bank. Near downtown Newark it makes an abrupt easterly bend, then south around Ironbound, joining the Hackensack River at the northern end of Newark Bay, a back bay of New York Harbor.
Pollution
The Lower Passaic River Watershed suffered severe pollution during the 19th and 20th centuries because of industrial waste discharges such as dioxin, mercury, PCBs, Ammonia, and many other contaminants to the river’s sediments and improper waste disposal practices on adjacent land. Although the health of the river has improved due to implementation of the 1972 Clean Water Act and other environmental legislation, and the decline of industry along the river, it still suffers from substantial degradation of water quality. The sediment at the mouth of the river near Newark Bay remains contaminated by pollutants such as dioxin. The dioxin was generated principally by the Diamond Shamrock Chemical Plant in Newark, as a waste product resulting from the production of the Agent Orange defoliation chemical used during the Vietnam War. The cleanup of the dioxin contamination on the bottom of the river is the subject of a major environmental lawsuit regarding the responsibility for the cleanup. In 2008, the EPA reached a settlement with Occidental Chemical Corporation and Tierra Solutions Inc. to clean a portion of the polluted river. A New Jersey Superior Court judge, ruling in July and September 2011, stated that Occidental and Maxus Exergy Corporation (a subsidiary of YPF) are liable for remediation in other portions of the river [
The New Jersey Department of Environmental Protection (NJDEP) issued notices in 2009 banning commercial fishing and advising the general public that fish caught in the tidal Passaic River (from Dundee Dam to the mouth at Newark Bay) should not be eaten [
In April 2014 EPA announced a $1.7 billion plan to remove 4.3 million cubic yards (3.3 × 106 m3) of toxic mud from the bottom of lower eight miles (13 km) of the river. It is considered one of the most polluted stretches of water in the nation and one of the biggest clean-ups project ever undertaken [
Electrometer (pH meter); A pH meter with expanded millivolt scale capable of 0.1 mV resolution between −700 and +700 mV such as Hanna Instruments Model 9017.
Ammonia selective electrode, Model NH-35-0002 (Analytical Sensors, Inc. Sugar land TX.) Equipped with a membrane sleeve (part MD-1004-4).
Magnetic starrier, thermally insulated.
Fluoropolymer coated magnetic bar.
Enviro MIDI-Dist TM (Vineland, NJ) distillation apparatus with the appropriate glassware for distillation [
All solutions and standards have been prepared at room temperature and keep in refrigerator at 4˚C.
Ammonia Free water (Lab reagent grade water prepared by a DI water system).
Sodium hydroxide, ACS Reagent Grade – 10N. Prepared by dissolving 400 gm NaOH in 800 ml water while stirring. Cool and dilute to 1000 mL with water from ammonia free water.
Stock ammonium chloride solution. Prepared by dissolving 3.819 grams of anhydrous NH4Cl (ACS Reagent Grade) dried at 100˚C for at least one hour in 200 mL while stirring, and dilute to 1000 mL in a volumetric flask.
1.0 mL= 1.0 mgN = 1.22 mg NH3
Standard ammonium chloride solutions. Prepare a series if standard solutions covering the concentrations of 50, 25, 10, 5, 1, 0.5 and 0.1 mg NH3-N/Liter by making dilutions of stock NH4Cl solution from above with water as shown below:
First make a working standard by diluting the stock solution by a factor of 10
| Working Std. Volume (mL) | Dilute to (mL) | NH3-N Concentration (mg/L) |
|---|---|---|
| 0.0 0.1 0.5 1.0 5.0 10.0 25.0 50.0 | 100 100 100 100 100 100 100 100 | 0.0 0.1 0.5 1.0 5.0 10.0 25.0 50.0 |
(10 mL in 100 mL).
Now dilute the working std. solution as per
NaOH/EDTA—10N solution for removing heavy metals that form ammonia complexes. Dissolve 400 gm sodium hydroxide ( CAS -1310-73-2) Reagent grade in 800 mL water. Add 45.2 gm Na4EDTA = 4H2O ( ACS Reagent Grade) and stir to dissolve. Cool and dilute to a 1000 mL in a volumetric flask. Keep all reagents on a dark cool place.
Electrode filling solution supplied by Analytical Sensors Inc. This solution is a precalibrated ammonium chloride solution.
Sodium tetraborate—0.025 M.
Prepare by dissolving 9.5 grams of Na2B4O7∙10H2O, ACS Reagent Grade in 200 mL water and dilute to 1000 ml with ammonia free DI water
Sodium thiosulfate solution (Dechlorinating reagent):
Dissolve 3.5 gm Na2S2O3∙5H2O, ACS Reagent Grade in 1000 mL ammonia free DI water. Add 0.4 mL of chloroform as a preservative.
Note: 1.0 mL of this solution will remove 1 mg/L of residual chlorine in 500 mL sample.
Borate buffer solution:
Add 88 mL 0.1N NaOH solution to 500 mL 0.025 M Na2B4O7 solution and dilute to 1 L with ammonia free DI water
Sulfuric acid—0.04N
Dilute 1.0 ml conc. H2SO4 to 1000 ml with ammonia free DI water.
Sodium hydroxide, ACS Reagent Grade—6N:
Dissolve 240 grams NaOH in 800 ml water while stirring. Cool and dilute to 1000 mL with ammonia free DI water.
Sample Collection:
The sampling has been followed NJDEP guidelines for collection, preservation and transport of water samples. The water samples have been collected from two foot deep flowing water level, and sediment as well in the Passaic River. The 10 laboratory cleaned sample plastic bottle have been used for sampling between 1 mile, from 10 spots of both sides of the river, and then mixed them up to make it 1 L. Sample was preserved with 2 mL of conc. H2SO4 per liter and stored at 4˚C [
This method is applicable to the measurement of ammonia nitrogen in drinking, surface and saline waters and domestic and industrial wastes and wastewater.
This method covers the range from 0.1 to 50 mg NH3-N per liter.
The application of this method for all samples always requires a preliminary distillation step.
Amines are a positive interference
Mercury and silver interfere by complexing with ammonia. When their presence is suspected add NaOH/EDTA solution.
Residual chlorine must be removed prior to distillation by treatment with sodium thiosulfate in water.
Add 50 mL DI water and 2.0 mL borate buffer, adjust pH to 9.5 with 6N NaOH solution, and add to a distillation flask. Add a few glass beads or boiling chips and use this mixture to steam out the distillation apparatus until distillate shows no traces of ammonia [
Neutralize sample pH to 7 before distillation. Then, to 50 mL of sample add 2.5 ml borate buffer then add 6 N NaOH dropwise with mixing and adjust to pH 9.5 using a pH meter and record pH on worksheet.
Transfer the sample to the reaction tube, followed by a pinch of boiling chips.
To the receiver tube add 5 mL of 0.04 N H2SO4. The tip of the long stem must be below the H2SO4 level.
Assemble the required number of set-ups in the distillation heating block and turn the tap water to cool the cold finger after ensuring all tubing connections are tight. Check for any leak before staring.
Set the block temperature to 190˚C and turn heat in.
Collect a minimum of 30 mL of distillate, preferably 40 mL.
Turn the heat off.
Unscrew the cap holding the long stem in the receiver tube and remove from all distillation positions to prevent any suck back of the distilled sample. When the long stem is disconnected gently let it rest at the bottom of the receive tube.
Dilute the distillate collected in the receiver tube to 50 mL graduation mark with ammonia free water.
Place a collection tray of individual beakers located directly below where the receiver tubes were removed to catch any further distillate. Distillation will continue because the heater block is still hot.
After each use clean exterior with a damp sponge.
When the heater temperature falls below 100oC, the next run can be started.
Before running standards, check the electrometer calibration as instructed in the instrument manual. If the electrode is functioning properly a tenfold change of NH3-N concentration produces a potential charge of about 59 mV.
Place 50 mL of each standard solution in 150 mL beaker. Immerse pH electrode and ammonia electrode in standard of lowest concentration and mix with a magnetic stirrer at low speed to minimize loss of ammonia from the solution. Record pH on worksheet.
Note: Possible loss of ammonia from the solution may cause cross contamination of other standards or sample(s). Handle the analysis in a way to minimize such possible cross contamination.
Maintain the same stirring rate and a temperature of about 25˚C throughout the calibration and testing procedures.
Add a sufficient volume of 10N NaOH solution (1 mL is usually sufficient) to raise the pH above 11.0 keeping the electrode in solution until a stable millivolt reading is obtained. Record the amount of NaOH added on the worksheet.
Note: 1) Do not add the NaOH solution before immersing the electrode.
2) If the presence of ammonia complexing metals (Ag or Hg) is suspected add instead 1 ml of NaOH/EDTA, reagent 2.2.4. above.
Repeat the above procedure with all the standards in an increasing order of concentration. Note the volume added.
Using the appropriate excel program obtain a plot of ammonia-N concentration in mg/L (on the log axis) vs. potential ion millivolts on the linear axis.
Dilute if necessary prior to measurement of potential to bring the NH3-N concentration to within the calibration curve range. Follow the procedure 3.4. and 3.5. for 50 mL of sample in 150 mL beakers. Record the stabilized potential of each unknown sample an convert the potential reading to the ammonia concentration using the standard curve regression equation: (via the excel program).
Note: Blank subtraction or correction is NOT permitted in this procedure.
Note: The ammonia selective electrode responds slowly below 1mg NH3-N/L; hence use longer time of electrode immersion (2 to 3 min.) to obtain stable readings.
Sample measurements: Follow the procedure record the stabilized potential of each unknown sample, blank, spiked and spiked sample, read the ammonia level directly in mg NH3-N/L using Ion Selective Ammonia Electrode (ISE) [
NH3 Selective Electrode Measurements
Most critical for reproducible measurements are good electrical connections between electrode and meter. Hanna uses adapter, picks up noise (±3 mV when touch benchtop, ±50 mV when touch ref connection, poor reproducibility day to day). Very good results (noise-free and reproducible) are obtained with JENCO Model-671p meter (battery operated), which provides direct connection of electrode to meter.
Also critical is the membrane. Follow the flow chart carefully. The membrane can be restored to good operating conditions by soaking overnight in DI water (fill with water, and put in beaker containing water).
Preparation: Prepare standards (50, 25, 10, 5 ppm directly from 1 mg/mL; 1, 0.5, 0.1 from 10 ppm). Prepare thymolphthalein (transition 8.3 to 10.5) by dissolving 0.04 g in 50 mL ethanol and adding 50 mL H2O. Prepare 50% KOH by weighing 250 g KOH pellets (Baker Analyzed Reagent) and adding 250 mL (or 250 g) of H2O. Mix in water bath in hood. When cool, transfer to plastic bottle. Note: Samples and standards must be adjusted to ≥ pH 11 for accurate determination of NH3 by electrode [
Other supplies: Stir plate, small (micro, 10mm length) stir bar, 50 mL beaker, paper towel torn into 8 parts. Holder for electrode. Pipets and volumetric flasks as needed for standards.
Protocol: Prepare electrode as directed. Electrode in DI water should have reading of 175 mV. Put 40 mL (use graduated cylinder) of lowest concentration standard into dry beaker with stir bar, begin stirring (mark dial, turn to same place every time. Approximately 1/2 turn from off position, Corning stir/hotplate.) Lower electrode till it is, “2 - 3 mm” above stir bar. Position should be reproducible when use electrode holder. Add 10 drops of KOH using disposable plastic transfer pipet. After stable reading is achieved (see below), stop stir bar, raise electrode (DON'T MOVE HOLDER) and clamp with large wooden spring clamp. Empty beaker, rinse electrode and beaker with DI water, blot dry with section of paper towel. Continue to next concentration, no need to rinse graduated cylinder as follow increasing trend in standard concentration. Time for stable reading: 0.1 ppm, 5 - 10 min; 0.5 ppm, 2 - 5 min; 1 ppm, 1 - 2 min; all others, a minute or less.
Rinse beaker, electrode, and graduated cylinder thoroughly with DI water. Put DI water in beaker, stir; electrode reading should approach 175 mV.
Plot E vs. log10 [NH3]/ppm and obtain three slopes and intercepts: one for lowest three concentrations, one for highest three concentrations, and one for all the concentrations. Keep a running tabulation for QC purposes (
Additional Notes:
| NH3-N [mg/L] | Log [NH3-N] | E/mV | R2 | Calc C | Del E |
|---|---|---|---|---|---|
| 0.1 | −1 | 110.1 | 0.09 | ||
| 0.5 | −0.3 | 64.7 | 1 | 0.55 | |
| 1.0 | 0 | 48.5 | 0.9983 | 1.04 | 61.6 |
| 5.0 | 0.7 | 8.5 | 0.99833 | 5.08 | 56.2 |
| 10.0 | 1 | −9.2 | 0.9989 | 10.25 | 57.7 |
| 25.0 | 1.4 | −31.1 | 0.99908 | 24.43 | |
| 50.0 | 1.7 | −48 | 0.99923 | 47.76 | 56.5 |
| m | −58.06 | 49.49 | b | ||
| s_m | 0.72 | 0.74 | s_b | ||
| R2 | 0.9992 | 1.72 | s_y |
Note: Do not over-tighten outer electrode. It is spring loaded; once connector is threaded, there is no improvement in reading by tightening it. Over-tightening may press inner electrode against membrane causing damage.
Note: Outer body mass is 6.0 g when empty; add 3.5 mL IFS by mass. At end, check membrane integrity by noting mass of outer body + IFS, it should be 9.5 g.
Note: Replace IFS to bottle after measurements. IFS is NH4Cl solution of approximately 1000 ppm concentration.
Note: See attached notes regarding NH3 electrode preparation and troubleshooting, as well as preparation of standard solutions.
Sample: 1.001 mg [NH3-N]/L, Duplicate result: 0.897 mg [NH3-N]/L
Average: 0.949 [NH3-N] mg/L
%RPD calculation:
% RPD = Sample Result − Duplicate Result Average × 100 = 1 0. 96 %
% Recovery = Spiked Sample Result − Sample Result Actual Known Concentration × 100
mg NH3-N/Liter = A × B (50.0 + D)/(50.0 + C)
where:
A—Dilution factor (as applicable).
B—Concentration of NH3-N/L in mg/L units as obtained from calibration curve.
C—Volume of 10N NaOH (or 10N NaOH/EDTA, where applicable) added to calibration standards, in mL.
D—Volume of 10N NaOH (or 10N NaOH/EDTA, where applicable) added to sample, in mL.
50—Sample volume in ml.
Dissolved ammonia-Nitrogen (NH3-N) were measured using an ammonia selective electrode, which a pH meter with expanded millivolt scale capable of 0.1 mV, Hanna Instrument Model 9017. Ammonia concentrations were determined by the ammonia selective electrode method [
| WHAT | DF | E/mV | Log [NH3-N] | [NH3-N] mg/L |
|---|---|---|---|---|
| Blank | 1 | 196.9 | −2.6 | 0.003 |
| 0.1 mg/L ind | 1 | 103.3 | −0.95 | 0.112 |
| Sample | 1 | 49.3 | 0 | 1.001 |
| Sample Dup | 1 | 52.0 | −0.05 | 0.897 |
| Spike | 1 | 35.2 | 0.25 | 1.774 |
| Spike Dup | 1 | 34.4 | 0.26 | 1.832 |
| Ave | 0.95 | |||
| Precision | 10.96 | |||
| Spike amount | 0.1 | |||
| Recov 1 %1 | 0.773 77.3 | 0.1 mL × 1000 mg/L is 0.1 mg; in 100 mL | ||
| Recov 2 | 0.831 | |||
| %2 | 83.1 |
| Test # | Lab ID | Distilled | pH Adjustment (9.50) | Volume of sample distilled (mL) | Final Volume of Distillate (mL) | Distillate pH (2.00) | Volume of NaOH added 1.00 mL | Reading (mV) |
|---|---|---|---|---|---|---|---|---|
| 1 | Blank | No | 9.50 | 50 | 50 | 2.0 | 1.00 | 196.9 |
| 2 | Sample | Yes | 49.3 | |||||
| 3 | Sample dup | Yes | 52.0 | |||||
| 4 | 0.1 mg/L check std | Yes | 103.3 | |||||
| 5 | Sample Spiked | Yes | 35.2 | |||||
| 6 | Sample Spiked Dup | Yes | 34.4 | |||||
| 7 | 10 mg/L Check Std. | Yes | -9.2 |
has been found 1.001 mg NH3-N/L and duplicate 0.897 mg NH3-N/L respectively. Percent spiked and spiked recovery result has been found 77.3% and 83.1% Respectively (
Run a method blank with each set of samples.
Determine precision and accuracy for every 20 samples or once a month if less than 20 samples are analyzed. Precision between the sample and duplicate must be less than 10% and the accuracy for the spike recoveries must be between 80% - 120%.
To determine accuracy run a method spike and spike duplicate. Perform the spiking every 20 samples or once a month if less than 20 samples are analyzed. Add enough spiking solution so that the added concentration (or absolute amount) is within the calibration curve.
A calibration curve must be analyzed every three months with a correlation coefficient of greater than or equal to 0.995 (
A second source QC check must be analyzed every 20 samples or once a month if less than 20 samples are analyzed in that month. Recovery must be within 10% of the true value.
Each day samples are analyzed a check standard from the same source as the curve must be analyzed. Recovery must be within 10% of the true value.
| Matrix Spike Recovery | Matrix Spike Recovery Duplicate | Average Spike Recovery |
|---|---|---|
| %RMS = 77.3% | %RMSD = 83.1% | %R = 80.2% |
It is desirable to conduct the analysis of unknown samples in a hood to avoid the possibility of generating high concentration of ammonia vapors and to minimize cross contamination of samples.
Solution containing ammonia-N in concentrations higher than 40 mg/L must be treated for ammonia destruction prior to discharge into the sewer line.
The authors declare no conflicts of interest regarding the publication of this paper.
Yildiz, Y., Karadag, R., Cheema, M. and Sayedahmed, M. (2022) Ion Selective Electrode Determination of Ammonia Nitrogen in Passaic River Waste Water in New Jersey Essex County Area. American Journal of Analytical Chemistry, 13, 96-107. https://doi.org/10.4236/ajac.2022.133008