Benzene separation method

Benzene separation method, Total:182 items.

The international standard classification for "Benzene separation method" includes: Other products of the chemical industry , Chemical analysis , Ferrous metals , Adhesives , Analytical chemistry , Aluminium and aluminium alloys , Other non-ferrous metals and their alloys , Workplace atmospheres , Aromatic hydrocarbons , Equipment for processing of minerals , Metalliferous minerals , Veterinary medicine , Protection against crime , Solid fuels , Pesticides and other agrochemicals , Power stations in general , Abrasives .

The Chinese standard classification for "Benzene separation method" includes: Basic standards and general methods for catalyst , Basic standards and general methods for water treatment agent , Steel and iron alloy analysis method , Adhesives , Basic organic chemicals , Heavy metals and their alloys , Rare metals and their alloys analysis method , Labor sanitation , Light metals and their alloys analysis method , Separating machinery , Animal quarantine, veterinary and epidemic prevention , Crime judging technology , Coal petrography , Culture, education and drawing instruments, notebooks and cards , Basic standards and general methods for pesticides , Electric power testing technique , Material and component for instrument and meter , Grinding material and apparatus , Precious metals and their alloys .

Professional Standard - Chemical Industry

HG 5-1342-1980 Determination method of free phenol content of phenolic resin
HG/T 2983-1987 Analytical Method of Content for Phenyl Maleic Hydrazide (Former GB 8203-87)
HG/T 4681-2014 Analytical method of chemical composition in the catalyst for nitrobenzene hydrogenation to aniline
HG/T 3525-2003 Industrial circulating cooling water-Determination of aluminium-Spectrometric method using pyrocat

General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China

GB/T 14352.15-1993 Methods for chemical analysis of tungsten ores and molybdenum ores. Determination of germanium content. Distillation separation-phenyl fluorone cetyltrimethyl-ammonium bromide phtometric method
GB/T 7781-1987 The model designation of separators
GB/T 12688.9-2011 Test method of styrene for industrial use—Part 9:Determination of trace benzene—Gas chromatographic method
GB/T 13747.18-2022 Methods for chemical analysis of zirconium and zirconium alloys—Part 18：Determination of vanadium content—N-benzoyl-N-phenyl hydroxylamine spectrophotometry and inductively coupled plasma atomic emission spectrometry
GB/T 223.41-1985 Methods for chemical analysis of iron,steel and alloy--The anion-exchange separation-pyrogallol photometric method for the determination of tantalum content
GB/T 20975.13-2008 Methods for chemical analysis of aluminium and aluminium alloys - Part 13：Determination of vanadium content N-benzoyl-Nphenylhydroxylamine spectrophotometric method
GB/T 7781-2005 The model designation of separator
GB/T 11898-1989 Water quality--Determinatoin of free chlorine and total chlorine--Spectrophotometric method useing N,N-diethyl-1,4 phenylenediamine
GB/T 18653-2002 Methods for isolation and identification of campylobactor fetus
GB/T 14074.13-1993 Testing methods for wood adhesives and their resins—Method for dtermination of free phenol content
GB/T 16055-1995 Workplace air―Determination of diphenyl-diphenyl ether―Ultraviolet spectrophotometric method
GB/T 223.42-1985 Methods for chemical analysis of iron,steel and alloy--The anion-exchange separation-bromopyrogallol red photometric method for the determination of tantalum content
GB 223.41-1985 Methods for chemical analysis of iron,steel and alloy; The anion-exchange separation-pyrogallol photometric method for the determination of tantalum content
GB/T 6987.30-2001 Aluminium and aluminum alloys method after extraction - diphenyl-carbon diethylol hydrazine spectrophotometric method for the determination of chromium content
GB/T 10895-1989 Centrifuger and Separator-Measurement method of mechanical vibration
GB/T 10895-2004 Centrifuge and separator—Measurement method of mechanical vibration
GB/T 30053-2013 Determination of Benzene, toluene and xylene in crude benzene
GB/T 6987.13-2001 Aluminium and aluminium alloys-Determination of copper content-N-benzoyl-Nphenylhydroxylamine spectrophotometric method
GB/T 223.45-1994 Methods for chemical analysis of iron, steel and alloy The cupral separation-xylidyl blue Ⅱphotometric method for the determination of magnesium content
GB/T 7781-2018 Separator—Model designation
GB 223.45-1985 Methods for chemical analysis of iron, steel and alloy--The cupral separation-xylidyl blue 2 photometric method for the determination of magnesium content
GB/T 223.12-1991 Methods for chemical analysis of iron,steel and alloy--The sodium carbonate separation-diphenyl carbazide photometric method for the determination of chromium content
GB 223.42-1985 Methods for chemical analysis of iron,steel and alloy; The anion-exchange separation-bromopyrogallol red photometric method for the determination of tantalum content

Group Standards of the People's Republic of China

T/ZNX 004-2020 Analytical method for effective components of fenbutatin technical
T/YZXMR 001-2021 Isolation and culture method of dental pulp stem cells
T/CPCIF 0316-2023 Technical specifications of membrane separation coupling method for benzene series offgas treatment project
T/SXCIES 002-2020 Crude benzol- Determination of moisture content
T/PZSGXH 001-2021 Determination of free phenol content in phenolic piywood

Professional Standard - Public Safety Standards

GA/T 204-1999 Methods of qualitative and quantitative analysis for benzene toluene ethyl benzene dimethyl benzene in blood and urine

Professional Standard - Coal

MT/T 371-1994 Determination method of sulfur ion in coal mine water p-aminodimethylaniline colorimetric method
MT/T 807-1999 Separation of vitrinite group in bituminous coal

未注明发布机构

ASTM RR-D02-1185 1984 D4425-Test Method for Oil Separation from Lubricating Grease by Centrifuging (Koppers Method)
ASTM RR-D16-2002 2020 D7883-Test Method for Determination of 4-Carboxybenzaldehyde and p-Toluic Acid in Purified Terephthalic Acid by Weak Anion Exchange High Performance Liquid Chromatography
ASTM RR-D16-1072 2019 D7883-Test Method for Determination of 4-Carboxybenzaldehyde and p-Toluic Acid in Purified Terephthalic Acid by Weak Anion Exchange High Performance Liquid Chromatography
ASTM RR-D16-1047 2013 D7883-Test Method for Determination of 4-Carboxybenzaldehyde and p-Toluic Acid in Purified Terephthalic Acid by Weak Anion Exchange High Performance Liquid Chromatography
ASTM RR-D16-1021 1997 D6142-Test Method for Analysis of Phenol by Capillary Gas Chromatography
ASTM RR-D16-1033 2004 D7057-Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography (External Standard)
ASTM RR-D16-1028 2002 D0852-Test Method for Solidification Point of Benzene

国家市场监督管理总局、中国国家标准化管理委员会

GB/T 39765-2021 Determination of benzene,methylbenzene,ethylbenzene,dimethybenzene in stationery—Gas chromatographic method
GB/T 41225-2021 Limit and determination of free phenols in phenoxy carboxylic acid herbicides

Military Standard of the People's Republic of China-General Armament Department

GJB 1059.3-1990 Test methods of phenolic resin for ablative materials--Test of free phenols
GJB 533.28-1988 Detection methods for 45 components of submarine cabin air. Determination of benzene, toluene, ethylbenzene, xylene, and 1,2-dichloroethane content by gas chromatography.
GJB 533.33-1991 Detection method of air components in submarine cabin. Determination of cumene, n-propylbenzene, tert-butylbenzene, n-butylbenzene, 1,3,5-trimethylbenzene (including other butylbenzene) and 1,2,4-trimethylbenzene in gas phase. chromatography
GJB 1059.3A-2020 Test methods of phenolic resin for ablative materials—Part 3：Test of free phenols
GJB 533.33A-2021 Part 33 of the method for detecting air components in submarine cabins: Cumene, n-propylbenzene, tert-butylbenzene, n-butylbenzene, sec-butylbenzene, 1,3,5-trimethylbenzene (including other butylbenzene), 1,2, 4-Determination of trimethylbenzene content b
GJB 2205-1994 Satellite separation test method

Professional Standard - Electricity

DL/T 1077-2007 Determination for organic leachables of styrene ion exchange resins(Dynamic)

Professional Standard - Machinery

JB/T 10043-1999 0
JB/T 10043-2012 Method for abrasive grain recovery from surface coated abrasives
JB/T 9493.7-1999 Method for chemical analysis of manganin and novokostant resistance alloy The EDTA titrimetric method for the determination of aluminum content after separation with ammonium benzoate

Professional Standard - Geology

DZ 52-1987 Method for separating kerogen from rocks

Professional Standard - Ferrous Metallurgy

YB/T 5023-1993 Method for the determination of the distillation process of crude benzol
YB/T 5024-1993 Method for the determination of the distillation process of refined heavy benzol

Professional Standard - Commodity Inspection

SN/T 1086-2002 Procedure of isolation and identification for camplylobactor fetus

Heilongjiang Provincial Standard of the People's Republic of China

DB23/T 2077-2018 Determination of sodium dodecylbenzenesulfonate in water by high performance liquid chromatography separation with ultraviolet detection

中华人民共和国国家质量监督检验检疫总局、中国国家标准化管理委员会

GB/T 33913.1-2017 Method for chemical analysis of tris(triphenylphosphine) rhodium(I)chloride―Part 1:The determination of rhodium content―Inductively coupled plasma atomic emission spectrometry

Anhui Provincial Standard of the People's Republic of China

DB34/T 1333-2011 Determination of Benzene, Toluene and Xylene by Liquid Chromatography

Professional Standard - Environmental Protection

HJ 586-2010 Water quality-Determination of free chlorine and total chlorine-Spectrophotonetric method N,N-diethyl-1,4-phenylenediamine

RU-GOST R

GOST 11235-1975 Phenolformaldehyde resins. Methods for determination of free phenol
GOST 22019-1985 Synthetic rubbers. Method for determination of free styrene and alpha-methyl styrene
GOST 6433.6-1984 Electrical insulating materials. Methods for determination of ionic foreign matters by extraction
GOST 31734-2012 Fuel oils. Method for determination of water and sediment by centrifugation method
GOST 32269-2013 Petroleum bitumens. Method of separation into four fractions
GOST 33839-2016 Confectionery. Method for determination of mass fraction of benzoic acid
GOST 13496.6-1971 Mixed feed. Method of detachment of fungi
GOST 17601-1990 Marine centrifugal separators. Acceptance and methods of tests
GOST 2706.12-1974 Benzene hydrocarbons and allied products. Method of determination of benzene freezing point

Korean Agency for Technology and Standards (KATS)

KS M 6693-2008 Test method for free 2-mercaptobenzothiazole in benzothiazyl disulfide(MBTS)
KS M 1910-2009 Phthalic anhydride for industrial use－Methods of test－Determination of free acidity－Potentiometric method
KS I 2211-2011 Methods for determination of benzene in flue gas
KS M 1910-2002(2007) Phthalic anhydride for industrial use－Methods of test－Determination of free acidity－Potentiometric method
KS M 2194-1996 TESTING METHOD FOR benzenes
KS M 1678-2008(2018) Test method for benzeneㆍtolueneㆍxylene
KS I 2206-2011 Methods for determination of phenols in exhaust gas
KS F 2229-2016 Measuring method for the chloride ion content of polystyrene composite wood wool cement boards
KS M 1678-2023 Test method for benzeneㆍtolueneㆍxylene
KS F 2229-2009 Measuring method for the chloride ion content of polystyrene composite wood wool cement boards
KS M 2050-1996(2021) Testing method for oil separation of lubricating greases
KS M 2050-1996(2016) Testing method for oil separation of lubricating greases
KS M 6516-2016 Testing methods for SBR latex
KS M 1911-2002(2007) Phthalic anhydride for industrial use－Methods of test－Determination of phthalic anhydride content－Titrimetric method
KS M 3011-1990(2001) TESTING METHODS FOR POLYSTYRENES
KS M 3011-1985 TESTING METHODS FOR POLYSTYRENES
KS M 1989-2002(2012) Phthalic and adipic for industrial use－Determination of free alcohols content－Spectrometric method
KS F 2598-2011 Standard test method for distribution of total chloride ion in concrete
KS M 5481-1984 Test methods for the presence of benzene of paint

Indonesia Standards

SNI 7461-2008 Testing methods of modified aspalth solubility in toluen using centrifuge tools
SNI 06-4824-1998 Test methods for free chlorine content in water by visible light spectrophotometers in diethyl phenylendiamine (DPD)
SNI 03-6894-2002 Test method for asphalt content from asphalt mixtures by centrifuge

SCC

UNE 70105-5:1985 PHTHALIC ANHYDRIDE FOR INDUSTRIAL USE. METHODS OF TEST. PART 5: DETERMINATION OF FREE ACIDITY. POTENTIOMETRIC METHOD
AWWA WQTC53002 Field-Separation Methods for Arsenic
CEI 10-11:1997 Gassing characteristics of insulating liquids due to the effect of electric fields with ionizing action
AENOR UNE 70105-5:1985 Phthalic anhydride for industrial use. Determination of free acidity. Potentiometric method.
DANSK DS/EN ISO 119:1998 Plastics - Phenol-formaldehyde mouldings - Determination of free phenols - Iodemetric method

American Society for Testing and Materials (ASTM)

ASTM D5546-94a Standard Test Method for Solubility of Asphalt Binders in Toluene by Centrifuge
ASTM D6563-05(2010)e1 Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography
ASTM D5546-09 Standard Test Method for Solubility of Asphalt Binders in Toluene by Centrifuge
ASTM D5546-01 Standard Test Method for Solubility of Asphalt Binders in Toluene by Centrifuge
ASTM D5044-06(2012) Standard Test Method for Rubber Compounding Materialsmdash;Free 2-Mercaptobenzothiazole (MBT) in Benzothiazyl Disulfide (MBTS)
ASTM D6563-05e1 Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography
ASTM D3760-02e1 Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography
ASTM D6563-05 Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography
ASTM D6563-12 Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography
ASTM D3760-18 Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography
ASTM D5044-06 Standard Test Method for Rubber Compounding Materials8212;Free 2-Mercaptobenzothiazole (MBT) in Benzothiazyl Disulfide (MBTS)
ASTM D7883-13 Standard Test Method for Determination of 4-Carboxybenzaldehyde and p -Toluic Acid in Purified Terephthalic Acid by Weak Anion Exchange High Performance Liquid Chromatography
ASTM D6563-11 Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography
ASTM D7057-23 Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography (External Standard)
ASTM D4492-07 Standard Test Method for Analysis of Benzene by Gas Chromatography
ASTM D6563-11a Standard Test Method for Benzene, Toluene, Xylene (BTX) Concentrates Analysis by Gas Chromatography
ASTM D5044-06(2017) Standard Test Method for Rubber Compounding Materials&x2014Free 2-Mercaptobenzothiazole (MBT) in Benzothiazyl Disulfide (MBTS)
ASTM D5044-02 Standard Test Method for Rubber Chemicals-Free 2-Mercaptobenzothiazole (MBT) in Benzothiazyl Disulfide (MBTS)
ASTM D4492-03 Standard Test Method for Analysis of Benzene by Gas Chromatography
ASTM D6563-00 Test Method for Benzene, Toluene, Xylene, (BTX) Concentrates Analysis by Capillary Column Gas Chromatography
ASTM D4425-19 Standard Test Method for Oil Separation from Lubricating Grease by Centrifuging (Koppers Method)
ASTM D4492-98 Standard Test Method for Analysis of Benzene by Gas Chromatography
ASTM D4425-09(2014) Standard Test Method for Oil Separation from Lubricating Grease by Centrifuging (Koppers Method)
ASTM D4425-97 Standard Test Method for Oil Separation From Lubricating Grease by Centrifuging (Koppers Method)
ASTM D7304-14 Standard Test Method for Determination of Denatonium Ion in Engine Coolant by HPLC
ASTM D4425-09 Standard Test Method for Oil Separation From Lubricating Grease by Centrifuging (Koppers Method)
ASTM D4425-97(2002) Standard Test Method for Oil Separation From Lubricating Grease by Centrifuging (Koppers Method)
ASTM D7057-18 Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography (External Standard)
ASTM D3160-16 Standard Test Method for Phenol Content of Cumene (Isopropylbenzene) or AMS (α&x2013Methylstyrene)
ASTM D6832-13(2018) Standard Test Method for the Determination of Hexavalent Chromium in Workplace Air by Ion Chromatography and Spectrophotometric Measurement Using 1,5-diphenylcarbazide
ASTM D6832-08 Standard Test Method for the Determination of Hexavalent Chromium in Workplace Air by Ion Chromatography and Spectrophotometric Measurement Using 1,5-diphenylcarbazide
ASTM D4492-10 Standard Test Method for Analysis of Benzene by Gas Chromatography
ASTM D3160-20 Standard Test Method for Phenol Content of Cumene (Isopropylbenzene) or AMS (α–Methylstyrene)
ASTM D3797-03 Standard Test Method for Analysis of o -Xylene by Gas Chromatography
ASTM D1274-95(2000) Standard Test Methods for Chemical Analysis of Pentachlorophenol
ASTM D6832-13e1 Standard Test Method for the Determination of Hexavalent Chromium in Workplace Air by Ion Chromatography and Spectrophotometric Measurement Using 1,5-diphenylcarbazide
ASTM D3049-89(1996)e1 Standard Test Method for Synthetic Anionic Ingredient by Cationic Titration
ASTM D2462-90(1995) Standard Test Method for Moisture in Wool by Distillation With Toluene
ASTM D3760-02 Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography
ASTM D2567-68(1978) Standard Method for MOLECULAR DISTRIBUTION ANALYSIS FOR MONOALKYLBENZENES BY MASS SPECTROMETRY
ASTM D1017-51(1978)e1 Test Method for Benzene and Toluene in 250F and Lighter Petroleum Products by Ultraviolet Spectrophotometry
ASTM D3797-04 Standard Test Method for Analysis of o -Xylene by Gas Chromatography
ASTM D3798-03 Standard Test Method for Analysis of p -Xylene by Gas Chromatography
ASTM D3797-00 Standard Test Method for Analysis of o -Xylene by Gas Chromatography
ASTM D3760-08 Standard Test Method for Analysis of Isopropylbenzene (Cumene) by Gas Chromatography
ASTM D3314-02(2012) Standard Test Method for Rubbermdash;Chemical Analysis for Polystyrene Blocks In SBR (Styrene-Butadiene Rubber) and Styrene-Reinforced Latices
ASTM D6832-02 Standard Test Method for the Determination of Hexavalent Chromium in Workplace Air by Ion Chromatography and Spectrophotometric Measurement Using 1,5-diphenylcarbazide

KR-KS

KS M 1678-2008(2023) Test method for benzeneㆍtolueneㆍxylene

CZ-CSN

CSN 64 0236-1963 Detection of free Amonia in phenol ormaldehyde mouldings Qualitative method)
CSN ON 73 6723-1963 Neutralization of phenol waste water from generating plants TAR SEPARATING DEVICE

International Organization for Standardization (ISO)

ISO 1389-5:1977 Phthalic anhydride for industrial use; Methods of test; Part V : Determination of free acidity; Potentiometric method

Japanese Industrial Standards Committee (JISC)

JIS K 0450-60-10:2007 Testing method for individual 4-nonylphenol isomers in industrial water and wastewater
JIS K 2421:1985 Methods for testing benzenes
JIS K 7240:1999 Plastics -- Phenol-formaldehyde mouldings -- Determination of free phenols -- Iodometric method
JIS K 6727-2:2012 Styrene.Part 2: Test method
JIS K 2256:1985 Testing methods for aniline point and mixed aniline point of petroleum products

YU-JUS

JUS H.B8.410-1985 Phthalic anhydride for industrial use. Determination of free acidity. Volumetric method
JUS H.G8.013-1980 Reagents. Hydrochk>ric acid. Determination offree chlorine content. o-Tolidine colorimetric method

German Institute for Standardization

DIN EN 14333-3:2005 Non fatty foods - Determination of benzimidazole fungicides carbendazim, thiabendazole and benomyl (as carbendazim) - Part 3: HPLC method with liquid/liquid-partition clean up; German version EN 14333-3:2004
DIN EN ISO 119:1998 Plastics - Phenol-formaldehyde mouldings - Determination of free phenols; Iodometric method (ISO 119:1977); German version EN ISO 119:1998
DIN EN ISO 119:1998-10 Plastics - Phenol-formaldehyde mouldings - Determination of free phenols; Iodometric method (ISO 119:1977); German version EN ISO 119:1998

British Standards Institution (BSI)

BS EN 14333-3:2004 Non-fatty foods - Determination of benzimidazole fungicides carbendazim, thiabendazole and benomyl (as carbendazim) - HPLC method with liquid/liquid-partition clean up
BS EN ISO 119:1998 Plastics - Phenol-formaldehyde mouldings - Determination of free phenols - Iodometric method
BS EN ISO 119:1978 Plastics. Phenol-formaldehyde mouldings. Determination of free phenols. Iodometric method
BS 6337-4:1984 General methods of chemical analysis. Method for determination of chloride ions by potentiometry
BS 684-2.36:1983 Methods of analysis of fats and fatty oils. Other methods. Determination of butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT)
BS 6829-1.2:1988 Analysis of surface active agents (raw materials). General methods. Method for determination of free alkalinity or free acidity

European Committee for Standardization (CEN)

EN 14333-3:2004 Non fatty foods - Determination of benzimidazole fungicides carbendazim, thiabendazole and benomyl (as carbendazim) - Part 3: HPLC method with liquid/liquid-partition clean up

Association Francaise de Normalisation

NF V03-094-3:2004 Non fatty foods - Determination of benzimidazole fungicides carbendazim, thiabendazole and benomyl (as carbendazim) - Part 3 : HPLC method with liquid/liquid partition clean up.
NF EN 61619:1997 Liquid insulators - Contamination by polychlorinated biphenyls (PCB) - Determination method by gas chromatography on a capillary column
NF X42-200:1987 BIOTECHNOLOGY. SEPARATION METHODS. CLASSIFICATION.

IN-BIS

IS 5182 Pt.11-1982 Measurement method of air pollution part Ⅺ benzene

BE-NBN

NBN T 40-109-1988 Phenol-formaldehyde mouldings - Determination of free phenols - lodometric method

GSO

GSO ISO 119:2015 Plastics -- Phenol-formaldehyde mouldings -- Determination of free phenols -- Iodometric method
OS GSO 173:1994 METHODS OF TEST FOR BENZOIC ACID, SODIUM BENZOATE AND POTASSIUM BENZOATE USED IN PRESERVATION OF FOODSTUFFS

GOSTR

GOST 13496.6-2017 Mixed feed. Method of detachment of fungi

Canadian General Standards Board （CGSB)

CGSB 1-GP-71 METH 65.1-1995 Methods of Testing Paints and Pigments Detection of Benzene (Benzol)
CGSB 1-GP-71 METH 24.2-1980 Test Methods for Paints and Pigments Water Content Toluene Solubility Method

ES-UNE

UNE 84127:2021 Cosmetic raw materials.Determination of free chloroanilines in trichlorocarbanilide.

RO-ASRO

STAS 10545-1976 ALKYL-PHENOLS Determination of free phenol content
STAS 9493-1974 BENZOTHIAZOLYLDISULPHIDE Determination of free and total 2—mercaptobenzothiazole

PL-PKN

PN BN 6140-05-1964 Labeling of active substances in cationic artificial products using the p-toluidine method

AR-IRAM

IRAM 12 355-1962 2.Measurement of the melting point of 2.4 dichlorophenoxyacetic acid, 2,4,5 trichlorophenoxyacetic acid, 2.4 dichlorophenoxybutyric acid and other free acidic herbicides

TR-TSE

TS 1860-1975 TRITOLYL PHOSPHATE FOR INDUSTRIAL USE - DETERMINATION OF APPARENT FREE PHENOLS CONTENT - VOLUMETRIC METHOD