What chromatographic method is used to separate homologues?
What chromatographic method is used to separate homologues?, Total:145 items.
The international standard classification for "What chromatographic method is used to separate homologues?" includes: Protection against crime , Other non-ferrous metals and their alloys , Electronic components in general , Salts , Alcohols. Ethers , Surface active agents , Ambient atmospheres , Lead, zinc, tin and their alloys .
The Chinese standard classification for "What chromatographic method is used to separate homologues?" includes: Crime judging technology , Precious metals and its alloy analysis method , Electronic element in general , Coating , Petroleum geology exploration , Basic standards and general methods for chemical additive , Basic organic chemicals , Analysis methods for toxic substances in atmosphere , Heavy metals and their alloys analysis method .
Professional Standard - Public Safety Standards
- GA/T 930-2011 GC and chemistry examination methods for cyanogens ion in biology samples
- GA/T 1074-2013 GC-MS and LC-MS/MS examination methods for γ-hydroxybutyric acid in biological samples
- GA/T 933-2011 GC and GC-MS examination methods for monofluorocetate anion in biological samples
Hebei Provincial Standard of the People's Republic of China
- DB13/T 2499.2-2017 Determination methods for liquid mixtures - Part 2: Simultaneous determination of total sulfur and total chlorine (ion chromatography)
国家市场监督管理总局、中国国家标准化管理委员会
- GB/T 40231-2021 Restricted substance in electrical and electronic products—Determination of hexavalent chromium—Ion chromatography method
- GB/T 39285-2020 Method for chemical analysis of palladium compounds—Determination of chlorine content—Ion chromatography
未注明发布机构
- ASTM RR-D01-1085 1995 D5910-Test Method for Determination of Free Formaldehyde in Emulsion Polymers by Liquid Chromatography
- ASTM RR-D15-1025 2009 D5827-Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography
- ASTM RR-D16-1052 2014 D7359-Test Method for Total Fluorine, Chlorine and Sulfur in Aromatic Hydrocarbons and Their Mixtures by Oxidative Pyrohydrolytic Combustion followed by Ion Chromatography Detection (Combustion Ion Chromatography-CIC)
- ASTM RR-D02-1737 2012 D7591-Test Method for Determination of Free and Total Glycerin in Biodiesel Blends by Anion Exchange Chromatography
- DIN EN ISO 18314-4 E:2021-03 Analytical Colorimetry Part 4: Metameric Index for Sample Pairs with Varying Light Sources (Draft)
工业和信息化部
- YS/T 1497-2021 Analysis method for platinum compounds Determination of impurity anion content Ion chromatography
- YS/T 1496-2021 Analysis method for palladium compounds Determination of impurity anion content Ion chromatography
- YS/T 1380-2020 Method for chemical analysis of rhodium compounds. Determination of the chloride ion and nitrate ion contents. Ion chromatography method
Professional Standard - Agriculture
- SN/T 5055.1-2018 Analysis of biodiesel - Part 1: Determination of sodium, potassium, calcium, and magnesium cations - Ion chromatography method
国家质量监督检验检疫总局
- SN/T 4815-2017 Determination of fluorinion in animals for import and export-IC method
Professional Standard - Commodity Inspection
- SN/T 1545-2005 Method for the concurrent determination of benzene toluene xylene and diisocyanate in solvent coatings for import and export - Gas chromatography method
- SN/T 3919-2014 Determination of water-soluble chloride content in iron ores - Ion chromatography
Professional Standard - Geology
- DZ/T 0279.22-2016 Analysis methods for regional geochemical sample. Part 22: Determination of chlorine and bromine contents by ion chromatography
- DZ/T 0279.23-2016 Analysis methods for regional geochemical sample. Part 23: Determination of iodine contents by ion chromatography
Professional Standard - Petroleum
- SY/T 6009.5-2003 Test method of samples of geochemical exploration for oil and gas Part 5: Determination of free hydrocarbons Gas chromatography
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
- GB/T 9984.3-1988 Sodium tripolyphosphate for industrial use--Separation by ion exchange chromatography and determination of the different phosphate forme
- GB/T 9984.3-2004 Sodium tripolyphosphate for industrial use-Separation by ion exchange chromatography and determination of the different phosphate forms
- GB/T 14571.5-2016 Test method of monoethylene glycol for industrial use―Part 5:Determination of chloride ion―Ion chromatography
Professional Standard - Meteorology
- QX/T 218-2013 Determination of Volatile Organic Compound in Atmosphere - Sampling with Sampling Can and Gas Chromatography-mass Spectrum Combination Analysis Method
Shandong Provincial Standard of the People's Republic of China
- DB37/T 4434-2021 Ambient air—Determination of 57 kinds of ozone precursor compounds—Collected inspecially-prepared canisters and analyzed by gas chromatography-flame ionization detector/mass spectrometer
Professional Standard - Environmental Protection
- HJ 1261-2022 Stationary source emission―Determination of benzene and its analogies ―Bags sampling/Direct injection―gas chromatography
Group Standards of the People's Republic of China
- T/ZSZJX 010-2023 Ambient air-Determination of 104 volatile organic compounds Collected in canisters and analyzed by gas chromatography-hydrogen flameionization detector/mass spectrometry
Professional Standard - Non-ferrous Metal
- YS/T 928.6-2013 Methods for Chemical Analysis of Nickel Cobalt Manganese Composite Hydroxide Part 6: Determination of Sulfate Ion Contents Ion Chromatography
- YS/T 1593.4-2023 Methods for chemical analysis of crude lithium carbonate— Part 4:Determination of anion contents— Ion chromatography
US-CFR-file
- CFR 1-51.7-2014 General provisions. Part51:Incorporation by reference. Section51.7:What publications are eligible?
- CFR 40-80.580-2014 Protection of Environment. Part80:Regulation of fuels and fuel additives.Section80.580:What are the sampling and testing methods for sulfur?
- CFR 2-180.500-2014 Grants and agreements. Part180:Omb guidelines to agencies on governmentwide debarment and suspension (nonprocurement). SubpartE:System for award management exclusions. Section180.500:What is the purpose of the System for Award Management Exclusions (SAM E
- CFR 29-4000.3-2014 Labor. Part4000:Filing, issuance, computation of time, and record retention. Section4000.3:What methods of filing may I use?
British Standards Institution (BSI)
- BS EN ISO 18314-4:2024 Analytical colorimetry - Metamerism index for pairs of samples for change of illuminant
- BS EN 17294:2019 Animal feeding stuffs. Methods of sampling and analysis. Determination of organic acids by Ion Chromatography with Conductivity Detection (IC-CD)
- BS EN ISO 18314-4:2021 Analytical colorimetry. Metamerism index for pairs of samples for change of illuminant
- 19/30376495 DC BS EN 17374. Animal feeding stuffs: Methods of sampling and analysis. Determination of inorganic arsenic in animal feed by anion-exchange HPLC-ICPMS
- 19/30354953 DC BS ISO 18314-4. Analytical colorimetry. Part 4. Metamerism index for pairs of samples at change of illuminant
- BS EN 17050:2017 Animal feeding stuffs: Methods of sampling and analysis. Determination of iodine in animal feed by ICP-MS
- 23/30456807 DC BS EN ISO 18314-4. Analytical colorimetry - Part 4. Metamerism index for pairs of samples for change of illuminant
ES-UNE
- UNE-EN 17294:2020 Animal feeding stuffs - Methods of sampling and analysis - Determination of organic acids by Ion Chromatography with Conductivity Detection (IC-CD)
- UNE-EN ISO 18314-4:2022 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020)
- UNE-EN ISO 19340:2018 Water quality - Determination of dissolved perchlorate - Method using ion chromatography (IC) (ISO 19340:2017)
Association Francaise de Normalisation
- NF EN 17294:2019 Aliments des animaux - Méthodes d'échantillonnage et d'analyse - Dosage des acides organiques par chromatographie ionique avec détection conductimétrique (CI-DC)
- NF V18-217*NF EN 17294:2019 Animal feeding stuffs - Methods of sampling and analysis - Determination of organic acids by Ion Chromatography with Conductivity Detection (IC-CD)
- NF T33-313-4*NF EN ISO 18314-4:2021 Analytical colorimetry - Part 4 : metamerism index for pairs of samples for change of illuminant
- NF EN 17374:2020 Animal feed - Methods of sampling and analysis - Determination of inorganic arsenic content in animal feed, by anion exchange HPLC and high-frequency induced plasma mass spectrometry (I...
- XP T60-234*XP CEN ISO/TS 22115:2021 Animal and vegetable fats and oils - Separation of lipid classes by capillary gas chromatography (fingerprint method)
- NF EN 17212:2019 Animal foodstuffs - Methods of sampling and analysis - Determination of melanin and cyanuric acid contents by liquid chromatography coupled with mass spectrometry (LC-MS/MS)
- NF EN 13523-3:2021 Pre-painted sheets - Test methods - Part 3: color difference and metamerism - Comparison using instruments
SCC
- DANSK DS/EN 17294:2019 Animal feeding stuffs – Methods of sampling and analysis – Determination of organic acids by Ion Chromatography with Conductivity Detection (IC-CD)
- NS-EN 17294:2019 Animal feeding stuffs — Methods of sampling and analysis — Determination of organic acids by Ion Chromatography with Conductivity Detection (IC-CD)
- BS ISO 18314-4:2020 Analytical colorimetry-Metamerism index for pairs of samples for change of illuminant
- SPC GB/T 37385-2019 Test method for chloride content of silicon -- Ion chromatography method (TEXT OF DOCUMENT IS IN CHINESE)
- AWWA WQTC65960 Fluoride Testing Method: Improving Ion Chromatography Accuracy
- DANSK DS/ISO 18314-4:2021 Analytical colorimetry – Part 4: Metamerism index for pairs of samples for change of illuminant
- VDI 2457 BLATT 4-2000 Measurement of gaseous emissions — Chromatographic determination of organic compounds — Sampling of acidic components in alkaline aqueous solutions; analysis using ion chromatography
- NS-EN ISO 18314-4:2021 Analytical colorimetry – Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020)
- NS-EN 17504:2022 Animal feeding stuffs: Methods of sampling and analysis - Determination of gossypol in cotton seed and feeding stuff by LC-MS/MS
- DANSK DS/EN 17683:2023 Animal feeding stuffs – Methods of sampling and analysis – Determination of pyrrolizidine alkaloids in animal feeding stuff by LC-MS/MS
- NS-EN 17683:2023 Animal feeding stuffs - Methods of sampling and analysis - Determination of pyrrolizidine alkaloids in animal feeding stuff by LC-MS/MS
- NS-EN ISO 18314-4:2024 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2024)
- AWWA WQTC55174 An Improved Ion Chromatographic Method for Carboxylic Acids in Drinking Water
- DANSK DS/EN ISO 18314-4:2021 Analytical colorimetry – Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020)
- VDI 2457 BLATT 4-2000 Measurement of gaseous emissions — Chromatographic determination of organic compounds — Sampling of acidic components in alkaline aqueous solutions; analysis using ion chromatography
- DANSK DS/EN 17504:2022 Animal feeding stuffs: Methods of sampling and analysis – Determination of gossypol in cotton seed and feeding stuff by LC-MS/MS
- DIN EN 17294 E:2018 Draft Document - Animal feeding stuffs: Methods of sampling and analysis - Determination of organic acids by lon Chromatography with Conductivity Detection (IC-CD); German and English version prEN 17294:2018
- AWWA JAW34108 Journal AWWA — Using Ion Chromatography to Analyze Inorganic Disinfection By-Products
- VDI 3869 BLATT 4-2012 Measuring ammonia in outdoor air — Sampling with passive samplers — Photometric or ion chromatographic analysis
- VDI 3869 BLATT 3-2010 Measuring ammonia in the ambient air — Sampling with coated diffusion separators (denuders) — Photometric or ion chromatographic analysis
Danish Standards Foundation
- DS/ISO 18314-4:2021 Analytical colorimetry – Part 4: Metamerism index for pairs of samples for change of illuminant
- DS/EN ISO 18314-4:2021 Analytical colorimetry – Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020)
American National Standards Institute (ANSI)
- ANSI/ASTM D5827:1998 Test Method for Determination of Chloride in Engine Coolant by Ion Chromatography
CEN - European Committee for Standardization
- PREN 17294-2018 Animal feeding stuffs: Methods of sampling and analysis - Determination of organic acids by Ion Chromatography with Conductivity Detection (IC-CD)
American Society for Testing and Materials (ASTM)
- ASTM D3303-74 Method for Rapid Gas Chromatographic Estimation of Higher Boiling Homologues of Chlorinate Biphenyls for Capacitor Askarels
- ASTM D5827-95 Standard Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography
- ASTM D5827-95(2002) Standard Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography
- ASTM D5827-09 Standard Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography
- ASTM D5827-09e1 Standard Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography
- ASTM D5827-22 Standard Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography
- ASTM D5996-16 Standard Test Method for Measuring Anionic Contaminants in High-Purity Water by On-Line Ion Chromatography
- ASTM D4327-97 Standard Test Method for Anions in Water by Chemically Suppressed Ion Chromatography
- ASTM C1845-16 Standard Practice for The Separation of Lanthanide Elements from Uranium Matrices Using High Pressure Ion Chromatography (HPIC) for Isotopic Analyses by Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
- ASTM D5910-05 Standard Test Method for Determination of Free Formaldehyde in Emulsion Polymers by Liquid Chromatography
- ASTM D5910-05(2019) Standard Test Method for Determination of Free Formaldehyde in Emulsion Polymers by Liquid Chromatography
- ASTM D7359-14a Standard Test Method for Total Fluorine, Chlorine and Sulfur in Aromatic Hydrocarbons and Their Mixtures by Oxidative Pyrohydrolytic Combustion followed by Ion Chromatography Detection (Combustion Ion Chromatography-CIC)
- ASTM E1618-14 Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry
- ASTM D5910-96 Standard Test Method for Determination of Free Formaldehyde in Emulsion Polymers by Liquid Chromatography
- ASTM D4327-03 Standard Test Method for Anions in Water by Chemically Suppressed Ion Chromatography
- ASTM E2469-06 Standard Test Method for Chloride in Monoethylene Glycol by Ion Chromatography
- ASTM D5827-09(2015) Standard Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography
- ASTM D7359-14 Standard Test Method for Total Fluorine, Chlorine and Sulfur in Aromatic Hydrocarbons and Their Mixtures by Oxidative Pyrohydrolytic Combustion followed by Ion Chromatography Detection &40;Combustion Ion Chromatography-CIC&41;
- ASTM D4327-17 Standard Test Method for Anions in Water by Chemically Suppressed Ion Chromatography
- ASTM D5910-05(2012) Standard Test Method for Determination of Free Formaldehyde in Emulsion Polymers by Liquid Chromatography
- ASTM E1618-19 Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry
- ASTM D5542-04(2009) Standard Test Methods for Trace Anions in High Purity Water by Ion Chromatography
- ASTM D7359-23 Standard Test Method for Total Fluorine, Chlorine and Sulfur in Aromatic Hydrocarbons and Their Mixtures by Oxidative Pyrohydrolytic Combustion followed by Ion Chromatography Detection (Combustion Ion
- ASTM D4327-11 Standard Test Method for Anions in Water by Suppressed Ion Chromatography
- ASTM D7359-13 Standard Test Method for Total Fluorine, Chlorine and Sulfur in Aromatic Hydrocarbons and Their Mixtures by Oxidative Pyrohydrolytic Combustion followed by Ion Chromatography Detection lpar;Combustion Ion Chromatography-CICrpar;
- ASTM D7359-08 Standard Test Method for Total Fluorine, Chlorine and Sulfur in Aromatic Hydrocarbons and Their Mixtures by Oxidative Pyrohydrolytic Combustion followed by Ion Chromatography Detection (Combustion Ion Chromatography-CIC)
- ASTM D5996-05(2009) Standard Test Method for Measuring Anionic Contaminants in High-Purity Water by On-Line Ion Chromatography
- ASTM E1618-97 Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry
- ASTM E1618-06 Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry
- ASTM D7359-18 Standard Test Method for Total Fluorine, Chlorine and Sulfur in Aromatic Hydrocarbons and Their Mixtures by Oxidative Pyrohydrolytic Combustion followed by Ion Chromatography Detection (Combustion Ion
- ASTM E2881-13e1 Standard Test Method for Extraction and Derivatization of Vegetable Oils and Fats from Fire Debris and Liquid Samples with Analysis by Gas Chromatography-Mass Spectrometry
- ASTM E1618-06e1 Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry
- ASTM D7591-12(2017) Standard Test Method for Determination of Free and Total Glycerin in Biodiesel Blends by Anion Exchange Chromatography
- ASTM E1618-01 Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry
- ASTM E2881-18 Standard Test Method for Extraction and Derivatization of Vegetable Oils and Fats from Fire Debris and Liquid Samples with Analysis by Gas Chromatography-Mass Spectrometry
- ASTM D5542-16 Standard Test Methods for Trace Anions in High Purity Water by Ion Chromatography
- ASTM E1618-10 Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry
- ASTM D7328-07 Standard Test Method for Determination of Total and Potential Inorganic Sulfate and Total Inorganic Chloride in Fuel Ethanol by Ion Chromatography Using Aqueous Sample Injection
German Institute for Standardization
- DIN EN ISO 18314-4:2021-09 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020); German version EN ISO 18314-4:2021 / Note: To be replaced by DIN EN ISO 18314-4 (2023-02).
- DIN EN ISO 18314-4:2023-02 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO/DIS 18314-4:2022); German and English version prEN ISO 18314-4:2023 / Note: Date of issue 2023-01-06*Intended as replacement for DIN EN ISO 18314-4 (20...
- DIN EN ISO 18314-4:2024-04 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2024); German version EN ISO 18314-4:2024
- DIN 51438:2005-02 Testing of benzene and benzene homologues - Determination of the thiophene content of benzene - Gas chromatography
- DIN EN 17294:2019 Animal feeding stuffs - Methods of sampling and analysis - Determination of organic acids by lon Chromatography with Conductivity Detection (IC-CD)
- DIN 51438:2005 Testing of benzene and benzene homologues - Determination of the thiophene content of benzene - Gas chromatography
- DIN EN ISO 19340:2019-01 Water quality - Determination of dissolved perchlorate - Method using ion chromatography (IC) (ISO 19340:2017); German version EN ISO 19340:2017
International Organization for Standardization (ISO)
- ISO 18314-4:2023 Analytical colorimetry — Part 4: Metamerism index for pairs of samples for change of illuminant
- ISO 18314-4:2024 Analytical colorimetry — Part 4: Metamerism index for pairs of samples for change of illuminant
- ISO/FDIS 18314-4:2023 Analytical colorimetry — Part 4: Metamerism index for pairs of samples for change of illuminant
- ISO 18314-4:2020 Analytical colorimetry — Part 4: Metamerism index for pairs of samples for change of illuminant
CH-SNV
- SN EN ISO 18314-4:2021 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020)
Lithuanian Standards Office
- LST EN ISO 18314-4:2021 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020)
AT-ON
- OENORM EN ISO 18314-4:2021 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020)
European Committee for Standardization (CEN)
- prEN ISO 18314-4 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO/DIS 18314-4:2023)
- EN ISO 18314-4:2024 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2024)
- EN ISO/TS 22115:2021 Animal and vegetable fats and oils - Separation of lipid classes by capillary gas chromatography (fingerprint method)
- EN 16939:2017 Animal feeding stuffs: Methods of sampling and analysis - Detection of tylosin@ spiramycin and virginiamycin - Thin Layer Chromatography and bioautography
- EN ISO 18314-4:2021 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2020)
DIN
- DIN EN ISO 18314-4:2024 Analytical colorimetry - Part 4: Metamerism index for pairs of samples for change of illuminant (ISO 18314-4:2024)
VDI - Verein Deutscher Ingenieure
- VDI 2457 Blatt 4-1998 Gaseous emission measurement - Chromatographic determination of organic compounds - Sampling of acidic compounds in alkaline acqueous solution - Analysis by ion chromatography
- VDI 3869 Blatt 4-2010 Messen von Ammoniak in der Aussenluft - Probenahme mit Passivsammlern - Fotometrische oder ionenchromatografische Analyse
- VDI 3869 Blatt 5-1997 Measurement of acids and bases in ambient air - Measurement of lower carboxylic acids - Sampling in diffusion separators; determination by ion chromatography
AENOR
- UNE 84015:2001 Cosmetic raw materials. Fatty compounds which contain homologous series. Determination by gas chromatography.
- UNE-EN 13368-1:2014 Fertilizers - Determination of chelating agents in fertilizers by chromatography - Part 1: Determination of EDTA, HEEDTA and DTPA by ion chromatography
GSO
- GSO ISO 12010:2013 Water quality -- Determination of short-chain polychlorinated alkanes (SCCPs) in water -- Method using gas chromatography-mass spectrometry (GC-MS) and negative-ion chemical ionization (NCI)
- BH GSO ISO 15366-1:2017 Nuclear fuel technology -- Chemical separation and purification of uranium and plutonium in nitric acid solutions for isotopic and isotopic dilution analysis by solvent extraction chromatography -- Part 1: Samples containing plutonium in the microgram ...
- GSO ISO 15366-1:2015 Nuclear fuel technology -- Chemical separation and purification of uranium and plutonium in nitric acid solutions for isotopic and isotopic dilution analysis by solvent extraction chromatography -- Part 1: Samples containing plutonium in the microgram ...
IT-UNI
- UNI CEN ISO/TS 22115:2021 Animal and vegetable fats and oils - Separation of lipid classes by capillary gas chromatography (fingerprint method)
NL-NEN
- NEN 6364-1987 Vegetable and animal oils and fats - Separation of the sterols from the unsaponifiable matter by thin layer chromatography
RU-GOST R
- GOST R 57033-2016 Liquid petroleum products. Determination of trace chlorides, fluorides, and bromides by ion chromatography with sample combustion method (CIC)
Standard Association of Australia (SAA)
- AS 3741:1990 Recommended practice for chemical analysis by ion chromatography