Determination of SRN in Liquid (water soluble) Urea-Formaldehyde Fertilizers Method Forum February 24, 2016 Albuquerque, New Mexico

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1 Determination of SRN in Liquid (water soluble) Urea-Formaldehyde Fertilizers Method Forum February 24, 2016 Albuquerque, New Mexico Tessenderlo Kerley, Inc. tkinet.com 1

SRN Fertilizers Slow Release Fertilizers (SRN): Slow Release Fertilizers are solid or liquid fertilizer products that release (convert to a plant available form) their nutrients at a slower rate

2 SRN Fertilizers Slow Release Fertilizers (SRN): Slow Release Fertilizers are solid or liquid fertilizer products that release (convert to a plant available form) their nutrients at a slower rate relative to a reference soluble product. This may be accomplished by biodegradation and/or by limited solubility and/or by hydrolysis or other recognized chemical or biochemical means. Some examples include solid fertilizers such as: methylene urea (MU), Magnesium Potassium Phosphate and bio solids, and liquid fertilizer such as triazone. The product may provide longevity claims when compared to an appropriate reference material. Solid: Liquid: IBDU, CDU, Nutralene N-Sure, NBN 30, Clear N, Last N Tessenderlo Kerley, Inc. tkinet.com 2

3 Manufacturers of Liquid Water soluble SRN Fertilizers Helena Koch Yara Tessenderlo Kerley Arclin Advachem Sadepan Agrium Tessenderlo Kerley, Inc. tkinet.com 3

4 Production From Urea, Formaldehyde, Formalin (or UFC) r from Urea, Formaldehyde, Formalin (or UFC) and ammonia. under controlled conditions to form a liquid ureaformaldehyde condensate product. Tessenderlo Kerley, Inc. tkinet.com 4

5 Base Catalyzed Urea Formaldehyde Condensate Reaction Base H 2 N Urea NH 2 + H H H 2 N NH CH 2 H + CH 2 H HN NH CH 2 H MMU DMU Tessenderlo Kerley, Inc. tkinet.com 5

6 Urea Formaldehyde Condensate Reaction Acid Catalyzed Acid H 2 N NH 2 + H H H 2 N NH HN NH 2 + H 2 N NH HN NH HN NH 2 CH 2 CH 2 CH 2 MDU DMTU Tessenderlo Kerley, Inc. tkinet.com 6

7 Urea + Formaldehyde + Ammonia (gas or aqua) Tessenderlo Kerley, Inc. tkinet.com 7

8 HPLC Chromatogram Tessenderlo Kerley, Inc. tkinet.com 8

(28-0-0) UF Liquid product Composition? Monomethylol urea (MMU) 2% Dimethylol urea (DMU) 0.3% Methylene diurea (MDU) 1.00% Biuret 0.02-0.

9 (28-0-0) UF Liquid product Composition? Monomethylol urea (MMU) 2% Dimethylol urea (DMU) 0.3% Methylene diurea (MDU) 1.00% Biuret % HMT 1-2% Free Urea 14-15% verall, 22% of N is from urea & 78% of N is from SRN The minor components are about 5-8% 70% of the composition is a major component What is this major component? Tessenderlo Kerley, Inc. tkinet.com 9

10 1 H NMR Spectra in DMS

11 D 2 Added H NMR Spectra

12 13 C NMR Spectra in DMS

13 Major component of crystal. Green is unaccounted for electron density (error in structure)

14 Proposed Mechanism for the Formation of the Major Component Urea + Formaldehyde + Ammonia H 2 N NH 2 H N N N CH 2 H H + H 2 N NH 2 H N N N H N H + Ureaforms N-Sure C NH 2 5-Hydroxymethyltriazine Urea Tessenderlo Kerley, Inc. tkinet.com 14

15 15 Slow Release Pattern

16 SRN Determination SRN is coming from cyclic compound or chained compounds (MMU, DMU, etc). Free Urea does not provide SRN To accurately report the SRN one has to determine the Free Urea accurately. SRN is determined by subtracting the total Nitrogen present from the amount of free Urea Tessenderlo Kerley, Inc. tkinet.com 16

17 Aqueous Urea-Formaldehyde Fertilizer Products Each of existing products in the market claim certain Percent of SRN from 50-80%. Existing Method of Analyses AAC Methods (Urease, 1960) AAC Method (Liquid Chromatography, 1984) 1 AAC Method (Liquid Chromatography, 2008) 1 fficial Methods of Analysis (2000) 17th Ed., AAC INTER NATINAL, Gaithersburg, MD, Methods and Tessenderlo Kerley, Inc. tkinet.com 17

18 Test products 1. LF3060 (30 0 0), Koch Agronomic Services, LLC, 4111 E. 37 th St. N, Wichita, KS 67220, USA 2. CoRoN (28 0 0), Helena Chemical Company, 225 Schilling Blvd., Collierville, TN Arclin , Arclin Resins, Research & Technology, th St., Springfield, R Greenfeed (light Green liquid), Plant Food Company, 38Hightstown Cranbury Station Road, Cranbury, NJ Greenfeed (Dark Green liquid), Plant Food Company,38Hightstown Cranbury Station Road, Cranbury, NJ NDemand , Wilbur Ellis Agribusiness, 3300 S. Parker Road, Suite 500, Aurora, C 80014, USA 7. NDemand 30L, Wilbur Ellis Agribusiness, 3300 S. Parker Road, Suite 500, Aurora, C 80014, USA 8. Gradual N (30 0 0), WinfieldSolutions, LLC, 1080 County Road West, Shoreview, MN N 28 clear Fertilizer (28 0 0), Advachem, Route de Wallonie, Darse d Hautrage, BE 7334 Hautrage 10. N Sure (28 0 0), Tessenderlo Kerley, Inc., 2255 N. 44 th St., Suite 300, Phoenix, AZ 11. Trisert NB (26 0 0), Tessenderlo Kerley, Inc., 2255 N. 44 th St., Suite 300, Phoenix, AZ 12. Formolene Plus (30 0 0), Tessenderlo Kerley, Inc., 2255 N. 44 th St., Suite 300, Phoenix, AZ 18

19 Analyses of Twelve Fertilizer Samples for Urea by AAC Method Fertilizer Lab ID Total N* % Urea N Sample Lab 1 Lab 2 Mean Std. dev Average X Standard Deviation σ x Number of samples n Variance σ Pearson Correlation 0.99 T Stat 1.30 P(T<t) one tail 0.11 t Critical one tail 1.80 P(T<=t) two tail 0.22 T Critical two tail 2.20 * Note: Total N includes other forms of nitrogen in addition to unreacted (free) urea Tessenderlo Kerley, Inc. tkinet.com 19

20 Schematically comparisons of HPLC Results by two Labs Comparison of Urea analysis by Labs 1 & 2 % Urea N Lab 1 Lab Sample # Tessenderlo Kerley, Inc. tkinet.com 20

21 Urease Analyses of Twelve Fertilizer Samples & Comparisons with the HPLC Results for Urea Total N Fertilizer Sample % Urea N % Urea N % Urea N Urease Method AAC HPLC Method AAC (Means from two Labs) Difference Urease HPLC (Mean) Tessenderlo Kerley, Inc. tkinet.com 21

22 Comparisons of the Results by HPLC ( ) and by Urease Method (Powdered Sample) Product % Total N %SRN Claimed SRN Determination HPLC ( ) Method Urease Tessenderlo Kerley, Inc. tkinet.com 22

Difficulties with Existing Methods Urease Method Problems The Urease method is the method most commonly used in both industry and regulatory laboratories for urea in all types of fertilizers.

23 Difficulties with Existing Methods Urease Method Problems The Urease method is the method most commonly used in both industry and regulatory laboratories for urea in all types of fertilizers. However, for UF-based fertilizers, one or more of the UF-derived components inhibit the action of Urease enzyme. Method is dependent upon this quantitative action. Method Condition: 20 ml of 1% Urease Solution Urease activity should at least hydrolyze 0.1 g of Urea Tessenderlo Kerley, Inc. tkinet.com 23

24 Analyses of Urea using Different Sources of Urease Urease Source Urease Amount % Hydrolysis of urea from the amount used 0.1 g 0.3 g 0.6 g 1.0 g 1 20 ml (1% Sol.) ml Glycerol Ext ml Glycerol Ext ml (1% Sol.) ml (1% Sol.) tablets ml Glycerol Ext ml (1% Sol.) Tessenderlo Kerley, Inc. tkinet.com 24

25 AAC (Urease Method) vs. AAC (HPLC) Results for Analyses of Unreacted Urea in Urea Triazone Liquid Fertilizers amount used Sample Urease vs Urease HPLC Urease HPLC HPLC 1 A ml 1% Solution B C D A ml Glycerol Ext. B C D A ml Glycerol Ext. B C D A ml 1% Solution B C D A ml 1% Solution B C D A Two Tablets B B ml Glycerol Ext. C B ml Glycerol Ext. C A ml 1% Solution B C D Tessenderlo Kerley, Inc. tkinet.com 25

26 Urease Method Results ften Not Reproducible Type of Urease is important (powder, Tablet, Liquid form) Urease activities varies with different sources Interference from ureaform components Tessenderlo Kerley, Inc. tkinet.com 26

27 AAC HPLC Method Comparisons of results for sample #10, #11, and #12 by two HPLC Methods Sample # 10 (28 0 0) Sample # 11 (26 0 0) % Free Urea Sample #12 (30 0 0) (AAC ) (AAC 983.1) Lab 1 Lab 2 Lab Tessenderlo Kerley, Inc. tkinet.com 27

28 AAC HPLC Method Method is not reliable for determination of urea in the cited class of fertilizers because in most, if not all, cases, there is co-elution of a non-urea peak with The urea peak. Mobile Phase: Column: Detector: Water DS Refractive Index Tessenderlo Kerley, Inc. tkinet.com 28

29 Comparisons of the analytical results for Grade by AAC & AA Sample ID Samples Analyzed by Lab 1 Grade % Biuret Test 1 % Biuret Test 2 % Biuret Test 3 % Biuret Test 4 Average % Biuret STDEV By Method Sulfur coated urea Triazone Fertilizer Fertilizer A Fertilizer B By Method Sulfur coated urea Triazone Fertilizer Fertilizer A Fertilizer B By SRIC * Method (same as ) Sulfur coated urea Triazone Fertilizer Fertilizer A Fertilizer B * Shanghai Research Institute of Chemical Industry Testing Center Tessenderlo Kerley, Inc. tkinet.com 29

30 HPLC Method AAC fficial Method Liquid Chromatography First Action 2003, Final Action 2008 UV absorption detector 195 nm Mobile Phase: 85% Acetonitrile, 15% water Flow rate: 1.30 ml/min Mobile phase temp: Ambient Column temperature: o C Injection volume: 10 l HPLC Column A 250 x 4.6 mm amine (NH2) column with 5 packing is used for this separation We obtained the best results using Phenomenex. External Urea, Biuret, MMU, DMU, and HMTA Standards Tessenderlo Kerley, Inc. tkinet.com 30

31 Conclusions The AAC fficial Methods (Urease Method) and (HPLC Method) are frequently inaccurate and therefore not suitable for measuring the amounts of free and unreacted urea in liquid ureaformaldehyde condensate products. AAC fficial Method consistently provides more accurate analytical results for measuring the contents of free urea in these classes of fertilizers. The results have been accepted as a manuscript for the publication in the Journal of AAC International and will appear in the next issue. Tessenderlo Kerley, Inc. tkinet.com 31

Brief Introduction of Slow/Controlled Release Fertilizer Industry of China & Related Standards

Brief Introduction of Slow/Controlled Release Fertilizer Industry of China & Related Standards Gang LIU Shanghai Research Institute of Chemical Industry (SRICI) China National Technical Committee for Standardization