• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.3
• /
• pp.387-393
• /
• 2011

We analyzed the particle size distributions of three commercially available Devarda's alloy (DA) products, tested the nitrate recoveries of each particle size category, and examined the amounts of DA required for 100% recovery by varying $NO_3$-N concentration from 0.5 to 10 mg. We observed that use of DA coarser than 200 mesh resulted in poor analytical recovery (<80%). While the tested alloys were considered to be fine enough (>90% of the particles were less than 100 mesh), the recovery dramatically declined from 80% to 10% in a high concentration range (4 to 10 mg N). Satisfactory recovery was obtained by increasing the amount of finer DA (less than 300 or 450 mesh). However, there was no quantitative relationship between the amount of fine DA and nitrate recovered. Generally, the amount of nitrate reduced per unit DA decreased as the recovery efficiency declined. These results suggest that a sufficient amount of DA must be determined based on particle size distribution, and that treatment of at least two levels of DA and comparison of the subsequent change in nitrate recovery is required for soils containing high levels of nitrate. In addition, further studies are encouraged to account for the observed stoichiometric dis-equivalence of recovered nitrate N per unit mass of DA.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.2
• /
• pp.223-226
• /
• 2012

Liquid livestock manure (LLM) has been used as a nitrogen fertilizer source for horticulture plants. LLM contains organic nitrogen (N), ammonium, nitrate, and nitrite. The amount of nitrate and nitrite in LLM are usually small compared to the amount of ammonium in it and so they can be negligible if total nitrogen (N) concentration in LLM is higher than $1,000mg\;L^{-1}$. However, if total N concentration in LLM is less than $1,000mg\;L^{-1}$, the amount of nitrate and nitrite may affect total N concentration in LLM. Currently, Kjeldahl digestion method is mainly used for ammonium-N in LLM. Therefore, it is ineffective to analyze nitrate-N and nitrite-N. The objective of this study was to evaluate whether the total N concentrations are affected by the amount of nitrate-N and nitrite-N with diverse LLMs by Kjeldahl method (with and without Devarda's alloy after Conc. sulfuric acid digestion). Five liquid livestock manure samples were collected at swine farms in Ansung and Icheon. All LLM samples were stored at $25^{\circ}C$, subsampled at every $15^{th}$ day for 90 days, and analyzed for total N, ammonium-N, and nitrate-N. At the $90^{th}$ day, LLM samples were analyzed with and without Devarda's alloy after Conc. sulfuric acid digestion. Potassium nitrate, ammonium nitrate, and ammonium chloride were used to determine the N recovery percentages. Total N concentration ranged from 560 to $4,230mg\;L^{-1}$. Nitrate-Ns were found in all LLM samples, ranged from 21 to $164mg\;L^{-1}$. N recovery percentages with potassium nitrate were 0 % without Devarda's alloy and 100% with Devarda's alloy because adding Devarda's alloy facilitated nitrate-N into ammonium-N conversion. Total Ns were significantly different between two methods, with and without Devarda's alloy. Total N concentrations were $210mg\;L^{-1}$ at LLM 4 and $370mg\;L^{-1}$ at LLM 5 without Devarda's alloy and $290mg\;L^{-1}$ at LLM 4 and $490mg\;L^{-1}$ at LLM 5 with Devarda's alloy. These results suggest that if total N of LLM is less $1,000mg\;L^{-1}$, additional procedure such as adding Devarda's alloy can be used to estimate the total N and inorganic N better.

• Journal of Radiopharmaceuticals and Molecular Probes
• /
• v.4 no.2
• /
• pp.80-84
• /
• 2018

$[^{13}N]$Ammonia or $[^{13}N]NH_3$ is one of the most widely used PET tracer for the measurement of MBF. To produce $[^{13}N]NH_3$, devarda's alloy which contains aluminum, copper and zinc is used for the purpose of reduction from $^{13}N$-nitrate/nitrite to $[^{13}N]NH_3$. Since aluminum has neurotoxicity and renal toxicity, the amount of it should be carefully limited for the administration to the human body. Although USP and EP provide a way to identify the aluminum ion concentration, there are some difficulties to perform. Therefore, we tried to develop the modified method for verifying aluminum concentration of test solution. We compared color between test and standard solutions using chrome azurol S in pH 4.6 acetate buffer. We also tested color change of test and standard solutions according to pH, amounts and the order of reagent and time difference These results demonstrated that the color change of the solution can reflect quantitatively measure aluminum ion concentration. We hope the method is to be used effectively and practically in many sites where $[^{13}N]NH_3$ is produced.

• Analytical Science and Technology
• /
• v.20 no.1
• /
• pp.25-32
• /
• 2007

The measurement methods for total nitrogen in wastewater containing a high concentration of nitrogen were evaluated. (1) The UV spectrophotometry, (2) reduction-distillation Kjeldahl, (3) total Kjeldahl nitrogen, and (4) ion chromatography methods were applied. The experimental procedure of the UV spectrophotometric method was simple, but it produced large errors deriving from the dilution of samples and calibration standards. While, the reduction-distillation Kjeldahl method didn't need dilution, but the amount of Devarda's alloy and NaOH lead to large errors up to 50 mg/L. The levels of total nitrogen measured by each method were as follows: reduction-distillation Kjeldahl ($568.6{\pm}38.7mg/L$) > UV spectrophotometry ($527.3{\pm}9.6mg/L$) > total Kjeldahl nitrogen method ($494.7{\pm}21.4mg/L$) > ion chromatography method ($417.9{\pm}7.3mg/L$). Therefore, the reduction-distillation Kjeldahl method is preferred for wastewater with the high concentration of nitrogen. Optimal conditions for each experimental procedure, however, are needed to be confirmed, and the Standard Operation Procedure (SOP) for total nitrogen is required for reliable measurements.