505 DRY MATTER DETERMINATION FOR BOTANICAL MATERIALS
Feed: DM
Determination of the dry matter content based on the gravimetric loss of free water associated with heating to 105oC for a period of three hours.
Summary: This procedure is performed on botanical materials (plant and feed) that have been air- or oven-dried at 55-60oC and ground, to allow for correction of test results to 100% dry matter. If the moisture content of the sample as submitted is required, the Partial Dry Matter test should be requested. The method quantitatively determines the dry matter content based on the gravimetric loss of free water associated with heating to 105oC for a period of three hours. The method does not remove molecular bound water and is generally reproducible within 7%.
NFTA, Moisture Task Force Report, 2.2.2.5 Laboratory Dry Matter by Oven Drying for 3 hours at 105oC, 2001. pp. 1-3.
510 EXTRACTABLE NITRATE AND AMMONIUM IN BOTANICAL MATERIALS - DIFFUSION-CONDUCTIVITY ANALYZER METHOD
NO3-N, NH4-N
Total extractable nitrate and ammonium by 2% acetic acid extraction. Nitrate: Quantitative determination by zinc reduction and conductimetric analysis. Ammonium: Quantitative determination by conductimetric analysis.
Summary: This method quantitatively extracts soluble nitrate (NO3-N) and ammonium (NH4-N) in botanical materials based on an extraction with a solution of 2% acetic acid. Ammonium is determined by the diffusion-conductivity method based on the gaseous diffusing of ammonia (NH3) across a gas permeable membrane in the presence of excess base (KOH) and subsequent conductivity detection. Nitrate is determined by first reducing it to ammonium using a copper-zinc reduction column and subsequent measurement as described above. Concentrations of these nutrients are used to access plant overall nitrogen status and are correlated to plant response to nitrogen fertilization. Generally the method has a quantitative detection limit of 10 mg kg-1 (dry basis) and is generally reproducible within 8%.
Carlson, R. M., Cabrera, R. I., Paul, J. L., Quick, J. and Evans, R. Y. 1990. Rapid direct determination of ammonium and nitrate in soil and plant tissue extracts. Commun. Soil Sci. Plant Anal. 21:1519-1529.
512 EXTRACTABLE NITRATE AND AMMONIUM IN BOTANICAL MATERIALS - FLOW INJECTION ANALYZER METHOD
NO3-N, NH4-N
Total extractable nitrate and ammonium by 2% acetic acid extraction. Quantitative determination by flow injection analysis.
Summary: This method quantitatively extracts soluble nitrate (NO3-N) and ammonium (NH4-N) in botanical materials based on an extraction with a solution of 2% acetic acid. Nitrate is determined by reduction to nitrite via a copperized cadmium column. The nitrite is then determined by diazotizing with sulfanilamide followed by coupling with N-(1-naphthyl)ethlyenediaminie dihydrochloride. The absorbance of the product is measured at 520 nm. Ammonia is heated with salicylate and hypochlorite in an alkaline phosphate buffer. The presence of EDTA prevents precipitation of calcium and magnesium and sodium nitroprusside is added to enhance sensitivity. The absorbance of the reaction product is measured at 630 nm and is directly proportional to the original ammonia concentration. Concentrations of these nutrients are used to access plant overall nitrogen status and are correlated to plant response to nitrogen fertilization. Generally the method has a quantitative detection limit of 10 mg kg-1 (dry basis) and is generally reproducible within 8%.
Carlson, R. M., Cabrera, R. I., Paul, J. L., Quick, J. and Evans, R. Y. 1990. Rapid direct determination of ammonium and nitrate in soil and plant tissue extracts. Commun. Soil Sci. Plant Anal. 21:1519-1529.
Wendt, K. 1999. Determination of Nitrate/Nitrite by Flow Injection Analysis (Low Flow Method). QuikChem Method 10-107-04-1-A. Lachat Instruments, Milwaukee, WI.
Switala, K. 1997. Determination of Ammonia by Flow Injection analysis. QuikChem Method 10-107-06-1-A. Lachat Instruments, Milwaukee, WI.
515 TOTAL KJELDAHL NITROGEN (TKN)
By Special Request
Total reduced nitrogen by the wet oxidation of soil organic matter and botanical materials using a micro Kjeldahl procedure with sulfuric acid and digestion catalyst.
Summary: The Total Kjeldahl Nitrogen (TKN) method is based on the wet oxidation of soil organic matter and botanical materials using sulfuric acid and digestion catalyst and conversion of organic nitrogen to the ammonium form. Ammonium is determined using the diffusion-conductivity technique. The procedure does not quantitatively digest nitrogen from heterocyclic compounds (bound in a carbon ring), oxidized forms such as nitrate and nitrite, or ammonium from within mineral lattice structures. The method has a detection limit of approximately 0.001% N and is generally reproducible within 8%.
Note: This is the same method as SOP# 315.
Bremner, J. M. and Mulvaney, C. S. 1982. Nitrogen-total. p. 595-624. In: A. L. Page, et al. (ed.) Methods of soil analysis: Part 2. Chemical and microbiological properties. ASA Monograph Number 9.
Isaac, R. A. and Johnson, W. C. 1976. Determination of total nitrogen in plant tissue, using a block digestor. J. Assoc. Off. Anal. Chem. 59:98-100.
520 TOTAL NITROGEN & CARBON - COMBUSTION METHOD (THERMO FINNIGAN FLASH 1112 SERIES)
N, C (Total)
Combustion gas analyzer method for total nitrogen and total carbon.
Summary: This analytical method quantitatively determines the total amount of nitrogen and carbon in all forms in soil, botanical, and miscellaneous materials using a dynamic flash combustion system coupled with a gas chromatographic (GC) separation system and a thermal conductivity detection (TCD) system. The analytical method is based on the complete and instantaneous oxidation of the sample by "flash combustion" which converts all organic and inorganic substances into combustion gases (N2, NOx, CO2, and H20). The method has a detection limit of 0.01% and is generally reproducible within 5% (relative).
Method 972.43. Official Methods of Analysis of AOAC International, 16th Edition (1997), AOAC International, Arlington, VA.
525 TOTAL NITROGEN IN BOTANICAL MATERIALS - COMBUSTION METHOD (LECO FP528)
N
Total Nitrogen by Nitrogen Gas Analyzer utilizing induction furnace and thermal conductivity (LECO FP-528).
Summary: This method quantitatively determines the amount of nitrogen in all forms (ammonium, nitrate, protein and heterocyclic nitrogen) in botanical materials using an induction furnace and a thermal conductivity detector. Samples are ignited in an induction furnace at approximately 900°C, in helium and oxygen environment in a quartz combustion tube. An aliquot of the combustion gases is passed through a copper catalyst to remove oxygen and convert nitrous oxides to N2, scrubbed of moisture and carbon dioxide, and nitrogen content determined by thermal conductivity. The method has a detection limit of 0.01% nitrogen (dry basis) and is generally reproducible within 5%.
AOAC Official Method 990.03. Protein (Crude) in Animal Feed. 16th Edition (1997), AOAC International. Combustion Method. Arlington, VA.
530 EXTRACTABLE SULFATE-SULFUR IN BOTANICAL MATERIALS
SO4-S
Total extractable sulfate by 2% acetic acid extraction. Pre-concentration and isolation on anion exchange resin and quantitative measurement by atomic emission spectroscopy (ICP-AES).
Summary: This method quantitatively determines the amount of sulfate-sulfur (SO4-S) in botanical materials by extraction with a solution of 2% acetic acid. Sulfate contained within the extract is bound to an anion exchange resin, organo-sulfur compounds are removed by washing with 0.1 N HCl, and inorganic sulfur eluted with 1.0 N hydrochloric acid. Total sulfur is determined by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) at 182.04nm wavelength. The method may be semi-quantitative on some botanical materials which have a high anion exchange capacity. The method has a detection limit of 10 mg kg-1 (dry basis) and is generally reproducible within 8%.
Littlefield, E. S., Miller, R. O. and Carlson, R. M. 1990. Determination of sulfate-sulfur in plant tissue by inductively coupled plasma spectrometry. Commun. Soil Sci. Plant Anal. 21:1577-1586.
540 EXTRACTABLE PHOSPHORUS IN BOTANICAL MATERIALS
PO4-P
Total extractable phosphate by 2% acetic acid extraction. Quantitative determination by ascorbic acid reduction of phosphomolybdate complex and quantitative measurement by flow injection analysis.
Summary: This method quantitatively determines the amount of ortho-phosphate (PO4-P) in botanical materials by extraction with a solution of 2% acetic acid. Ortho-phosphate concentration in the extract is determined spectrophotometrically at 660nm by reacting with paramolybdate using an automated Flow Injection Analyzer (FIA). The method has shown to be correlated to plant deficiency and response to phosphorus fertilization. The method has a detection limit of 10 mg kg-1 (dry basis) and is generally reproducible within 8%.
Prokopy, W. R. 1995. Phosphorus in acetic acid extracts. QuikChem Method 12-115-01-1-C. Lachat Instruments, Milwaukee, WI.
550 EXTRACTABLE POTASSIUM IN BOTANICAL MATERIALS
K
Total K, extraction by 2% acetic acid extraction. Quantitative determination by atomic emission spectrometry (AES).
Summary: This method quantitatively extracts soluble potassium (K) present in botanical materials by extraction with a solution of 2% acetic acid. Potassium is quantitatively determined in the extract using atomic emission spectrometry (AES). Concentration of potassium is used to assess plant overall nutrient status and is correlated to plant response to potassium fertilization. Generally the method has a quantitative detection limit of 0.05% (dry basis) and is generally reproducible within 8%.
Johnson, C. M. and Ulrich, A. 1959. Analytical methods for use in plant analysis. Bulletin 766. Berkeley: University of California, Agricultural Experiment Station. p. 26-78.
560 EXTRACTABLE CHLORIDE IN BOTANICAL MATERIALS - CHLORIDOMETER METHOD
Cl
Total Cl by 2% acetic acid extraction and determination by chloridometer.
Summary: This method quantitatively determines the amount of chloride (Cl) in an acetic-acid extract of botanical materials. It is based upon the electrometric titration of the extract with silver using an automatic colorimetric chloride titrator. Plant tolerance to chloride can be related to the concentration of chloride in the extract. The method has a detection limit of 0.01% and is generally reproducible within 8%.
Johnson, C. M. and Ulrich, A. 1959. Analytical methods for use in plant analysis. Bulletin 766. Berkeley: University of California, Agricultural Experiment Station. p. 26-78.
561 EXTRACTABLE CHLORIDE IN BOTANICAL MATERIALS - ION CHROMATOGRAPHY METHOD
Cl
Cl by water extraction and analysis by ion chromatography.
Summary: This method determines the amount of chloride in botanical materials using a water extraction and analysis by ion chromatography with conductivity detection. The method has a detection limit of 0.01%. A 5 g sample is requested to allow for quality control samples and moisture determination but the test can be done on as little as 0.05 g if necessary.
Jones, J. B. 2001. Laboratory Guide for Conducting Soil Tests and Plant Analysis, pp. 227-228.
Dionex Application Note 154, Determination of Inorganic Anions in Environmental Waters Using a Hydroxide-Selective Column.
585 TOTAL SILICON-HF
Si
Silicon concentration by nitric acid/hydrogen peroxide/hydrofluoric acid digestion and ICP analysis.
Summary: This method quantitatively determines the concentration of silicon utilizing a nitric acid/hydrogen peroxide/hydrofluoric acid microwave digestion and analysis by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The method has a detection limit of 0.01% and on homogeneous sample material is generally reproducible within 8% (relative). The analysis is performed on 0.25 g sample material but 5 g is requested to allow for quality control and moisture determination.
Feng, X., Wu, S., Wharmby, A., and Wittmeier, A. Microwave digestion of plant and grain standard reference materials in nitric and hydrofluoric acids for multi-elemental determination by inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectrometry, 1999, 14, pp. 939-946.
590 TOTAL ELEMENTS (INCLUDES PHOSPHORUS, SULFUR, POTASSIUM, CALCIUM, MAGNESIUM, SODIUM, BORON, ZINC, MANGANESE, IRON, COPPER AND MOLYBDENUM)
Plant: P, S, B, Ca, Mg, Na, Zn, Mn, Fe, Cu, Al, As, Ba, Cd, Cr, Co, Pb, Mo, Ni, V
Microwave acid digestion/dissolution of sample and quantitative determination by AAS and ICP-AES.
Summary: This method quantitatively determines the concentration of P, S, Ca, Mg, K, Na, B, Zn, Mn, Fe, Cu, Mo and a variety of other elements utilizing a nitric acid/hydrogen peroxide microwave digestion and determination by atomic absorption spectrometry (AAS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The methodology utilizes a pressure digestion/dissolution of the sample and is incomplete relative to the total oxidation of organic carbon. K, Na, Zn, Cu, Mn, and Fe are analyzed by AAS and all others are analyzed by ICP-AES with vacuum spectrometer. The method has detection limits ranging from 0.1 mg Kg-1 to 0.01%. The method is generally reproducible within 8% for all analytes.
Note: This is the same method as SOP# 890.
Sah, R. N. and Miller, R. O. 1992. Spontaneous reaction for acid dissolution of biological tissues in closed vessels. Anal. Chem. 64:230-233.
Meyer, G. A. and Keliher, P. N.. 1992. An overview of analysis by inductively coupled plasma-atomic emission spectrometry. p. 473-516. In: A. Montaser and D.W. Golightly (ed.) Inductively coupled plasmas in analytical atomic spectrometry. VCH Publishers Inc.
594 SELENIUM
Se
Total selenium, nitric/perchloric acid digestion/dissolution of sample and determination by vapor generation by inductively coupled plasma atomic emission spectroscopy (ICP-AES).
Summary: This method is quantitative for selenium and is based on the wet oxidation of selenium bearing organic carbon and inorganic selenium compounds utilizing nitric, perchloric and sulfuric acids, reduction of selenate to selenite (IV), and determination by Vapor Generation Inductively-Coupled Plasma Emission Spectrometer (VG-ICP). The method has a detection limit of 0.10 ppm. It is generally reproducible within 10%. Tracy, M. L and G. Moeller. 1990. Continuous flow vapor generation for inductively coupled argon plasma spectrometric analysis. Part 1: Selenium. J. Assoc. Off. Anal. Chem. 73:404-410.
Tracy, M. L and Moeller, G. 1990. Continuous flow vapor generation for inductively coupled argon plasma spectrometric analysis. Part 1: Selenium. J. Assoc. Off. Anal. Chem. 73:404-410.
596 ARSENIC
Totals: (Complete Digestion) As
Total arsenic, nitric/perchloric acid digestion/dissolution of sample and determination by vapor generation by inductively coupled plasma atomic emission spectroscopy (ICP-AES).
Summary: This method is quantitative for arsenic utilizing nitric, perchloric and sulfuric acids, reduction of arsenate to arsenite, and determination by Vapor Generation Inductively-Coupled Plasma Emission Spectrometer (VG-ICP). The method has a detection limit of approximately 0.05 ppm. It is generally reproducible within 10%.
Tracy, M. L and Moeller, G. 1990. Continuous flow vapor generation for inductively coupled argon plasma spectrometric analysis. Part 2: Arsenic. J. Assoc. Off. Anal. Chem. 74:516-521.