HOME   Cart(7)   Quotation   About-Us Policy PDFs Standard-List
www.ChineseStandard.net Database: 189760 (18 Oct 2025)

GB 5009.191-2024 English PDF

US$619.00 · In stock
Delivery: <= 6 days. True-PDF full-copy in English will be manually translated and delivered via email.
GB 5009.191-2024: National food safety standards--Determination of chloropropanol and its fatty acid esters and glycidyl esters in food
Status: Valid

GB 5009.191: Evolution and historical versions

Standard IDContents [version]USDSTEP2[PDF] delivered inStandard Title (Description)StatusPDF
GB 5009.191-2024English619 Add to Cart 6 days [Need to translate] National food safety standards--Determination of chloropropanol and its fatty acid esters and glycidyl esters in food Valid GB 5009.191-2024
GB 5009.191-2016English839 Add to Cart 4 days [Need to translate] Determination of chloropropanol in foods Obsolete GB 5009.191-2016
GB/T 5009.191-2006English799 Add to Cart 4 days [Need to translate] Determination of chloropropanols in foods Obsolete GB/T 5009.191-2006
GB/T 5009.191-2003English319 Add to Cart 3 days [Need to translate] Determination of 3-monochloro-1, 2-propane-diol in foods Obsolete GB/T 5009.191-2003

PDF similar to GB 5009.191-2024


Standard similar to GB 5009.191-2024

GB 5009.183   GB 5009.189   GB 5009.198   GB 5009.205   GB 5009.182   

Basic data

Standard ID GB 5009.191-2024 (GB5009.191-2024)
Description (Translated English) National food safety standards--Determination of chloropropanol and its fatty acid esters and glycidyl esters in food
Sector / Industry National Standard
Classification of Chinese Standard X09
Word Count Estimation 36,347
Date of Issue 2/8/2024
Issuing agency(ies) National Health Commission of the People's Republic of China, State Administration for Market Regulation

GB 5009.191-2016: Determination of chloropropanol in foods

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Determination of chloropropanols in foods National Standards of People's Republic of China National standards for food safety Determination of Chloropropanol and Its Fatty Acid Esters in Food 2016-12-23 released 2017-06-23 Implementation National Health and Family Planning Commission of the People's Republic of China State Food and Drug Administration issued

Foreword

This standard replaces GB/T 5009.191-2006 "Determination of chloropropanol content in food", GB/T 18782-2002 "Condiment 3- Determination of Chloro-1,2-Propanediol ", SN/T 0548.1-2002" Inspection of 1,3-Dichloro-2-propanol and 2,3-Dichloro-1-propanol in Export Soy Sauce law". This standard compared with GB/T 5009.191-2006, the main changes are as follows. --- standard name changed to "food safety national standard food chloropropanol and its fatty acid ester content determination"; - the second method to increase D5-2-MCPD, D5-2, 3-DCP as the internal standard material, the purification steps by hand-filled diatomaceous earth chromatography column Changed to diatomite column purification; --- delete the third law; Determination of Chlorohydrin Fatty Acid Esters in Food by Gas Chromatography - Mass Spectrometry. National standards for food safety Determination of Chloropropanol and Its Fatty Acid Esters in Food

1 Scope

This standard specifies the determination of chloropropanol and chloropropanol fatty acid esters in food. This standard is applicable to the determination of chloropropanol and chloropropanol fatty acid esters in food. This standard includes the determination of 3-chloro-1,2-propanediol in food, the determination of multi-component content of chloropropanol in food, Determination of fatty acid ester content of a total of three detection methods. Determination of 3 - chloro - 1, 2 - propanediol in food of the first method Isotope dilution - gas chromatography - mass spectrometry

2 principle

This standard uses isotope dilution technology to D5-3-chloro-1,2-propylene glycol (D5-3-MCPD) as the internal standard. Add the internal standard sample to silicon Alginate as adsorbent, solid-phase support liquid-liquid extraction, with n-hexane - anhydrous ether solution (9 1) leaching to remove non-polar lipid components, 3-chloro-1,2-propanediol (3-MCPD) was eluted with anhydrous ether. It was derivatized with heptafluorobutyrylimidazole and determined by gas chromatography-mass spectrometry Quantitative quantity.

3 reagents and materials

Unless otherwise stated, the reagents used in this method are of analytical grade and water is a primary water specified in GB/T 6682. 3.1 Reagents 3.1.1 Ethyl acetate (C4H8O2). Chromatographic pure. 3.1.2 n-hexane (C6H14). pure chromatography. 3.1.3 anhydrous ether (C4H10O). need to re-steam before use, re-steaming plus a small amount of reduced iron powder. 3.1.4 Sodium chloride (NaCl). 3.1.5 anhydrous sodium sulfate (Na2SO4). bake at 120 ℃ for 4h before use. 3.1.6 Heptafluorobutyrylimidazole (C7H3F7N2O, CAS No. 32477-35-3). purity ≥98%. 3.2 reagent preparation 3.2.1 Sodium chloride solution (20%). Weigh 20g sodium chloride, add 80mL of water, stir to make sodium chloride fully dissolved. 3.2.2 n-Hexane - anhydrous ether solution (9 1). 450 mL of n-hexane and 50 mL of anhydrous ether were mixed uniformly. 3.3 standards 3.3.1 3-chloro-1,2-propanediol (3-MCPD) standard (C3H7ClO2, CAS No. 96-24-2). purity ≥98%. 3.3.2 D5-3-Chloro-1,2-Propanediol (D5-3-MCPD) Standard (C3D5H2ClO2). purity ≥98%. 3.4 standard solution preparation Note. After the standard solution is prepared, it is necessary to transfer to a very good brown glass container and store at -20 ℃. 3.4.1 3-MCPD and D5-3-MCPD standard stock solution (1000mg/L). accurately weighed 3-MCPD and D5-3-MCPD 10mg (accurate to 0.01mg), dissolved with ethyl acetate, were transferred to two 10mL volumetric flask, with ethyl acetate volume to the scale, Mix well. The shelf life is 2 years. 3.4.2 3-MCPD Standard Intermediate (10mg/L). Accurately Remove 3-MCPD Standard Stock (1000mg/L) 0.1mL in 10mL Volume bottle, diluted with n-hexane to the scale, mix. The shelf life is 1 year. 3.4.3 3-MCPD standard working solution (1mg/L). accurate removal of 3-MCPD standard intermediate (10mg/L) 1mL in 10mL capacity Bottle, diluted with n-hexane to the scale, mix. The shelf life is 6 months. 3.4.4 D5-3-MCPD standard working solution (10mg/L). accurate removal of D5-3-MCPD standard stock solution (1000mg/L) 0.25mL In 25mL volumetric flask, diluted with n-hexane to the mark, mix. The shelf life is 1 year. 3.4.5 3-MCPD series of standard working fluid. respectively, 3-MCPD standard working fluid (1mg/L) 0.01mL, 0.05mL, 0.1mL, 0.2 mL, 0.4 mL, 0.8 mL, 1.6 mL and 3-MCPD standard intermediate (10 mg/L) 0.32 mL in a well- (5 mL or 10 mL) in a clear plug (lid) glass tube, add 20 μL of D5-3-MCPD standard working solution (10 mg/L), respectively N-hexane to 2 mL to prepare a medium containing 3-MCPD of 10 ng, 50 ng, 100 ng,.200 ng, 400 ng, 800 ng, 1600 ng, 3200ng series of standard working fluid, which D5-3-MCPD quality is.200ng. Pro is now available. 3.5 Materials 3.5.1 diatomaceous earth. 3.5.2 airtight needle. 1mL. 3.5.3 glass column. column length 40cm, column diameter 2cm.

4 instruments and equipment

4.1 Gas Chromatography - Mass Spectrometer. 4.2 electronic balance. the sensibility of 1mg and 0.01mg. 4.3 Ultrasonic Oscillator. 4.4 Rotary Evaporator. 4.5 thermostat or other thermostat heater. 4.6 Vortex Oscillator. 4.7 Centrifuge.

5 Analysis steps

5.1 Preparation of the sample Liquid samples shaken; matrix uniform semi-solid samples and powdery solid samples directly measured; other samples need to homogenate crushed evenly. preparation Good samples are stored at 0 ° C to 5 ° C. 5.2 sample extraction 5.2.1 Liquid samples Weigh the sample 4g (accurate to 0.001g) in 50mL beaker, add D5-3-MCPD standard working solution (10mg/L) 20μL, add Into the sodium chloride solution (20%) 4g, ultrasonic mixing 5min, to be purified. 5.2.2 semi-solid and solid samples (no obvious residue after extraction of semi-solid and solid samples) Weigh the sample 4g (accurate to 0.001g) in 50mL beaker, add D5-3-MCPD standard working solution (10mg/L) 20μL, add Into the sodium chloride solution (20%) 6g, ultrasound 10min, to be purified. 5.2.3 Semi-solid and solid samples (semi-solid and solid samples with significant residue after extraction) Weigh the sample 4g (accurate to 0.001g) in 15mL centrifuge tube, add D5-3-MCPD standard working solution (10mg/L) 20μL, Add sodium chloride solution (20%) 15g, ultrasonic extraction 10min, centrifuge at 5000r/min 10min, remove the supernatant, to be purified. 5.3 Sample purification Take 5g diatomaceous earth, add the extract, mix well, place 10min. Take 5g of diatomite into the column (the bottom of the column filled with a small amount of glass wool). The mixture of the extract and the diatomaceous earth was charged into the chromatography Column, the upper layer plus 1cm height of anhydrous sodium sulfate. The eluate was discarded with 40 mL of n-hexane-anhydrous ether solution (9 1). use 150 mL of anhydrous ether was eluted with 3-MCPD (flow rate about 8 mL/min). The effluent was collected, 15 g of anhydrous sodium sulfate was added and mixed to absorb Moisture, placed 10min after the funnel filter. The filtrate was evaporated to near dryness (about 0.5 mL) at 35 ° C and dissolved with 2 mL of n-hexane Slag, and transferred to a well-sealed, properly sized (5 mL or 10 mL) transparent plug (cap) glass tube to be derivatized. 5.4 Derivative 0.04 mL of heptafluorobutyrylimidazole was added to the n-hexane solution with an airtight needle, immediately sealed, vortexed for 30 s, incubated at 70 ° C 20min. Remove the solution into room temperature, add 2mL sodium chloride solution (20%), vortex 1min, standing, so that the water phase and n-hexane phase, and water Phase clarified. The n-hexane phase was removed and about 0.3 g of anhydrous sodium sulfate was added for drying. The solution was transferred to a vial for gas chromatography Spectral determination. At the same time do 3-MCPD series of standard working fluid derivatization. 5.5 Preparation of blank sample solution Weigh the same mass of sodium chloride solution (20%) or blank sample, the following steps according to 5.2, 5.3 and 5.4 at the same time with the sample To investigate the presence of systemic contamination during sample determination. 5.6 Instrument reference conditions 5.6.1 Gas Chromatographic Reference Conditions 5.6.1.1 Column. A weakly polar capillary gas chromatography-mass spectrometer containing 5% phenylarylene polymer or 5% phenyl-methylpolysiloxane (Column length 30m, inner diameter 0.25μm, film thickness 0.25μm), or equivalent performance. 5.6.1.2 Carrier gas. helium, flow rate 1mL/min. 5.6.1.3 Inlet temperature. 250 ° C. 5.6.1.4 Injection volume. 1 μL, splitless injection, non-shunt time 0.5 min, solvent delay time 5 min. 5.6.1.5 Program temperature rise. 50 ℃ for 1min, to 2 ℃/min up to 90 ℃, then 40 ℃/min rose to 270 ℃, and keep 5min. 5.6.2 Mass Spectral Reference Conditions 5.6.2.1 Ion source. electron bombardment source (EI). 5.6.2.2 Ionization energy. 70eV. 5.6.2.3 Ion source temperature. 250 ° C. 5.6.2.4 Transmission line temperature. 280 ° C. 5.6.2.5 Scan mode. Select the ion monitoring mode (SIM). 5.6.2.6 Monitoring Ions. 3-MCPD Derivatives Quantitative ion m/z253, qualitative ion m/z275, m/z289, m/z291; D5-3- MCPD derivatives Quantitative ion m/z257, qualitative ion m/z 278, m/z294, m/z 296. 5.7 Production of standard curve The 1μL3-MCPD series of standard working solution of the derivative solution from low to high concentration into the gas chromatography-mass spectrometer, measured 3- MCPD and D5-3-MCPD derivatives, 3-MCPD and D5-3-MCPD in the 3-MCPD standard working solution Of the mass ratio of the abscissa to 3-MCPD and D5-3-MCPD derivatives of the peak area ratio for the vertical axis, draw the standard curve. 5.8 Determination of sample solution A 1 μL sample solution was injected into a gas chromatography-mass spectrometer, and the peak area was measured. According to the standard curve, 3-MCPD quality.

6 Analysis of the results of the expression

The content of 3-MCPD in the sample is calculated according to formula (1) X = A × f m × 1000 (1) Where. X - the content of 3-MCPD in the sample, in milligrams per kilogram (mg/kg); A - the mass of the 3-MCPD in the sample solution, in ng (ng); f --- Weigh the sample after the analysis of the dilution before the test; m --- the quality of the sample, in grams (g); 1000 --- conversion factor. The result of the calculation retains three significant digits.

7 precision

The absolute difference between the two independent determinations obtained under repeatability shall not exceed 20% of the arithmetic mean.

8 other

The detection limit of 3-chloro-1,2-propanediol in food was 0.005mg/kg and the limit of quantification was 0.01mg/kg. Determination of multi - component content of chloropropanol in food of the second method Isotope dilution - gas chromatography - mass spectrometry

9 principle

This standard uses isotope dilution technology to D5-3-chloro-1,2-propanediol (D5-3-MCPD), D5-2-chloro-1,3-propanediol (D5-2- (D5-1,3-DCP) and D5-2,3-dichloro-2-propanol (D5-2,3-DCP) Standard Sample added Internal standard, extracted with sodium chloride solution, purified by diatomite column, rinsed with n-hexane, washed with ethyl acetate, Acyl imidazole derived, by gas chromatography - mass spectrometry, internal standard method quantitative. 10 reagents and materials Unless otherwise stated, the reagents used in this method are of analytical grade and water is a primary water specified in GB/T 6682. 10.1 Reagents 10.1.1 Ethyl acetate (C4H8O2). Chromatographic purity. 10.1.2 n-hexane (C6H14). chromatographic purity. 10.1.3 Sodium chloride (NaCl). 10.1.4 anhydrous sodium sulfate (Na2SO4). bake at 120 ℃ for 4 h before use. 10.1.5 Heptafluorobutyrylimidazole (C7H3F7N2O, CAS No. 32477-35-3). purity ≥98%. 10.2 Preparation of reagents Sodium chloride solution (20%). 20g sodium chloride was weighed, 80mL water was added and the sodium chloride was stirred to dissolve completely. 10.3 standards 10.3.1 3-chloro-1,2-propanediol (3-MCPD) standard (C3H7ClO2, CAS No. 96-24-2). purity ≥98%. 10.3.2 D5-3-Chloro-1,2-Propanediol (D5-3-MCPD) Standard (C3D5H2ClO2). purity ≥98%. 10.3.3 2-chloro-1,3-propanediol (2-MCPD) standard (C3H7ClO2, CAS No. 497-04-1). purity ≥98%. 10.3.4 D5-2-Chloro-1,3-propanediol (D5-2-MCPD) Standard (C3D5H2ClO2). purity ≥98%. 10.3.5 1,3-Dichloro-2-propanol (1,3-DCP) standard (C3H6Cl2O, CAS No. 96-23-1). purity ≥98%. 10.3.6 D5-1,3-dichloro-2-propanol (D5-1,3-DCP) standard (C3D5HCl2O). purity ≥98%. 10.3.7 2,3-Dichloro-1-propanol (2,3-DCP) Standard (C3H6Cl2O, CAS No. 616-23-9). purity ≥98%. 10.3.8 D5-2,3-Dichloro-1-propanol (D5-2,3-DCP) Standard (C3D5HCl2O). purity ≥97%. 10.4 standard solution preparation Note. After the standard solution is prepared, it is necessary to transfer to a very good brown glass container and store at -20 ℃. 10.4.1 Chloropropanol and deuterated chloropropanol standard stock solution (1000mg/L). accurately weighed 3-MCPD, 2-MCPD, 1,3-DCP, 2,3-DCP, D5-3-MCPD, D5-2-MCPD, D5-1, 3-DCP and D5-2, 3-DCP standards each (10 to 10 mg) Do not dissolve with ethyl acetate, were transferred to 8 10mL volumetric flask, with ethyl acetate volume to the mark, mix. The shelf life is 2 years. 10.4.2 Chloropropanol standard intermediate (10mg/L). 3-MCPD, 2-MCPD, 1,3-DCP and 2,3-DCP standard Liquid (1000mg/L) 0.1mL in four 10mL volumetric flask, diluted with n-hexane to the scale, shake. The shelf life is 1 year. 10.4.3 Chloropropanol mixed standard working solution (1mg/L). Accurate removal of 3-MCPD, 2-MCPD, 1,3-DCP and 2,3-DCP standards (10mg/L) 1mL in 10mL volumetric flask, add n-hexane diluted to the mark, mix. The shelf life is 6 months. 10.4.4 Deuterated chloropropanol mixed standard working solution (10mg/L). D5-3-MCPD, D5-2-MCPD, D5-1, 3-DCP and D5-2, 3-DCP standard stock solution (1000mg/L) 0.1mL in 10mL volumetric flask, diluted with n-hexane to the mark, mix. Paul The deposit is one year. 10.4.5 Chloropropanol Series Standard working solution. Remove the standard working solution (1mg/L) of chloropropanol, 0.01mL, 0.05mL, 0.1 mL, 0.2 mL, 0.4 mL, 0.8 mL, 1.6 mL and chlorophenol standard intermediate (10 mg/L) each 0.32 mL (10 mL/L) in a suitable volume (5 mL or 10 mL) of clear plug (cap) glass tube, respectively, with deuterated chloropropanol, 20ng, plus n-hexane to 2mL, mixed with the preparation of containing chloropropanol, respectively, the quality of 10ng, 50ng, 100ng,.200ng, 400ng, 800ng, 1600ng, 3200ng series of standard working fluid, of which the quality of each deuterated chloropropanol is.200ng. Pro is now available. 10.5 Materials 10.5.1 Diatomite Column. 5g. 10.5.2 airtight needle. 1mL. 11 instruments and equipment 11.1 Gas Chromatography - Mass Spectrometer. 11.2 electronic balance. the sensibility of 1mg and 0.01mg. 11.3 Ultrasonic Oscillator. 11.4 nitrogen concentrator. 11.5 thermostat or other thermostat heater. 11.6 Vortex Oscillator. 11.7 Centrifuge. 12 Analysis steps 12.1 Sample preparation Liquid samples shaken; matrix uniform semi-solid samples and powdery solid samples directly measured; other samples need to homogenate crushed evenly. preparation Good samples are stored at 0 ° C to 5 ° C. 12.2 Sample extraction 12.2.1 Liquid samples Weigh the sample 4g (accurate to 0.001g) in 15mL glass centrifuge tube, add deuterated chloropropanol mixed standard working solution (10mg/L) 20μL, ultrasonic mixing 5min, to be purified. 12.2.2 Semi-solid and solid samples Weigh the sample 4g (accurate to 0.001g) in 15mL glass centrifuge tube, add deuterated chloropropanol mixed standard working solution (10mg/L) 20μL, add 4g sodium chloride solution (20%), ultrasonic extraction 10min, centrifuge at 5000r/min 10min, remove the supernatant, and then repeat Extraction 1, combined supernatant, to be purified. 12.3 Sample Purification The supernatant was transferred to a diatomite column and equilibrated for 10 min. Rinse with 10 mL of n-hexane and discard the effluent to 15 mL Ethyl acetate was used to wash the chloropropanol. The eluate was collected in a glass centrifuge tube and concentrated to near dryness (about 0.5 mL, preferably concentrated to dry) The residue was dissolved in 2 mL of n-hexane and transferred to a well-equipped, well-sized (5 mL or 10 mL) transparent plug (cap) glass tube , To be derivatized. 12.4 Derivative 0.04 mL of heptafluorobutyrylimidazole was added to the purification solution with a gas-tight needle, immediately sealed with a vortex, mixed for 30 s, incubated at 70 ° C 20min. The mixture was cooled to room temperature, 2 mL of sodium chloride solution (20%) was added and the mixture was vortexed for 1 min to separate the aqueous and n-hexane phases. Clear water. Transfer the n-hexane phase, add about 0.3 g of anhydrous sodium sulfate to dry, transfer the solution to the sample vial, for gas chromatography - quality Spectral determination. At the same time do chloropropene series of standard working fluid derivatization. 12.5 Preparation of blank sample solution Weigh the same mass of sodium chloride solution (20%) or blank sample, the following steps according to 12.2,12.3 and 12.4 and sample at the same time To investigate the presence of systemic contamination during sample determination. 12.6 Instrument reference conditions 12.6.1 Gas Chromatographic Reference Conditions 12.6.1.1 Column. weakly polar capillary gas chromatography-mass spectrometer containing 5% phenylarylene polymer or 5% phenyl-methylpolysiloxane (Column length 30m, inner diameter 0.25μm, film thickness 0.25μm), or equivalent performance. 12.6.1.2 Carrier gas. helium, flow rate 1mL/min. 12.6.1.3 Inlet temperature. 250 ° C. 12.6.1.4 Injection volume. 1μL, splitless injection, no split time of 0.5min, solvent delay time of 5min. 12.6.1.5 Program temperature rise. 50 ℃ for 1min, to 2 ℃/min up to 90 ℃, then 40 ℃/min rose to 270 ℃, and keep 5min. 12.6.2 Mass Spectral Reference Conditions 12.6.2.1 Ionization source. electron bombardment source. 12.6.2.2 Ionization energy. 70eV. 12.6.2.3 Ion source temperature. 250 ° C. 12.6.2.4 Transmission line temperature. 280 ° C. 12.6.2.5 Scan mode. Select the ion monitoring mode (SIM). 12.6.2.6 Monitoring of ions. see Table 1. Table 1 Monitoring ions for chloropropanol and its deuterated chloropropanol derivatives Name of compound Quantitative ions (m/z) Qualitative ion (m/z) 3-MCPD derivative D5-3-MCPD 253 275,289,291 D5-3-MCPD Derivatives - 257 278, 294, 296 2-MCPD derivative D5-2-MCPD 253 75,289,291 D5-2-MCPD Derivatives - 257 79,294,296 1,3-DCP derivatives D5-1,3-DCP 75 77,275,277 D5-1,3-DCP Derivatives - 79 81,278,280 2,3-DCP derivatives D5-2,3-DCP 75 77,111,253 D5-2,3-DCP Derivatives - 79 81,116,257 12.7 standard curve of the production The derivatization solution of 1μL chloropropanol series standard working solution was injected into the gas chromatograph-mass spectrometer according to the concentration from low to high, Alcohols and derivatives of deuterated chloropropanol, with the mass ratio of each chloropropanol and its corresponding deuterated chloropropanol to the abscissa, And the corresponding peak area ratio of the derivative of deuterated chloropropanol is the ordinate, and the standard curve is drawn. 12.8 Determination of sample solution A 1 μL sample solution was injected into a gas chromatography-mass spectrometer to measure the peak area of the derivatives of chloropropanol and deuterated chloropropanol. 13 Analysis of the results of the statement The content of chloropropanol in the sample is calculated according to formula (2) X = A × f m × 1000 (2) Where. X - the content of each chloropropanol in the sample, in milligrams per kilogram (mg/kg); A - the mass of the chloropropanol in the sample solution, in ng (ng); f --- Weigh the sample after the analysis of the dilution before the test; m --- the quality of the sample, in grams (g); 1000 --- conversion factor. The result of the calculation retains three significant digits. 14 precision The absolute difference between the two independent determinations obtained under repeatability shall not exceed 20% of the arithmetic mean. 15 other The detection limits of 3-MCPD, 2-MCPD, 1,3-DCP and 2,3-DCP in food were 0.002 mg/kg, 0.002 mg/kg, 0.005 mg/kg, 0.005 mg/kg, 0.01 mg/kg, 0.01 mg/kg, 0.005 mg/kg, 0.005 mg/kg, 0.005 mg/kg, Determination of Chlorohydrin Fatty Acids in Foodstuffs Gas chromatography - mass spectrometry 16 principle The deuterated chloropropanol fatty acid ester was added to the sample, extracted with n-hexane and subjected to ester bond cleavage reaction with sodium methoxide-methanol solution to make chloropropanol The fatty acid ester was converted to chloropropanol and the corresponding fatty acid methyl ester, the reaction was terminated with glacial acetic acid, the sodium bromide solution was added and the solution was washed with n- Liquid to remove the resulting fatty acid methyl ester and other non-polar impurities, then purify with diatomaceous earth column, elute with chloropropanol with ethyl acetate, Which was derivatized by heptafluorobutyrylimidazole and detected by gas chromatography-mass spectrometry and internal standard method. 17 reagents and materials Unless otherwise stated, the reagents used in this method are of analytical grade and water is a primary water specified in GB/T 6682. 17.1 Reagent 17.1.1 Methanol (CH4O). 17.1.2 Methyl tert-butyl ether (C5H12O). 17.1.3 Sodium methoxide (CH3ONa). 17.1.4 glacial acetic acid (CH3COOH). excellent grade pur...

Tips & Frequently Asked Questions:

Question 1: How long will the true-PDF of GB 5009.191-2024_English be delivered?

Answer: Upon your order, we will start to translate GB 5009.191-2024_English as soon as possible, and keep you informed of the progress. The lead time is typically 4 ~ 6 working days. The lengthier the document the longer the lead time.

Question 2: Can I share the purchased PDF of GB 5009.191-2024_English with my colleagues?

Answer: Yes. The purchased PDF of GB 5009.191-2024_English will be deemed to be sold to your employer/organization who actually pays for it, including your colleagues and your employer's intranet.

Question 3: Does the price include tax/VAT?

Answer: Yes. Our tax invoice, downloaded/delivered in 9 seconds, includes all tax/VAT and complies with 100+ countries' tax regulations (tax exempted in 100+ countries) -- See Avoidance of Double Taxation Agreements (DTAs): List of DTAs signed between Singapore and 100+ countries

Question 4: Do you accept my currency other than USD?

Answer: Yes. If you need your currency to be printed on the invoice, please write an email to [email protected]. In 2 working-hours, we will create a special link for you to pay in any currencies. Otherwise, follow the normal steps: Add to Cart -- Checkout -- Select your currency to pay.

Question 5: Should I purchase the latest version GB 5009.191-2024?

Answer: Yes. Unless special scenarios such as technical constraints or academic study, you should always prioritize to purchase the latest version GB 5009.191-2024 even if the enforcement date is in future. Complying with the latest version means that, by default, it also complies with all the earlier versions, technically.