Meeting the Requirements of ASTM D ( IP548/06 ) with Agilent 1200 LC Systems

Transcription

1 Meeting the Requirements of ASTM D ( IP548/06 ) with Agilent 1200 LC Systems M.Woodman, Chemical Analysis Solutions Unit, Wilmington, Delaware, USA M.Sierocinska, European Field Support Centre, Waldbronn, Germany

2 Agenda What is the source and application for ASTM D (and IP548/06)? Description of Recent ASTM D Method Updates New D / IP548/06 Method Requirements Alternate methods for biodiesel blends Recommendations for the best configuration Results from locally collected diesel samples Summary Page 2

3 Usage and Source of ASTM/IP/EN methods used ASTM D and IP548/06 measure aromatic hydrocarbon groups in petroleum distillates having specified boiling point ranges of o C. These methods are mainly applied to fuel analysis, particularly diesel motor fuel. Kerosene based fuels for aviation are covered by another related method ASTM ( is the source of ASTM methods. The Energy Institute ( is the source of the IP (sometimes referenced as EI) methods IP (or EI) and EN methods (European Committee for Standardization ) often have parallel ASTM methods The method revision designation is very important Page 3

4 Related IP, EN and ASTM Methods IP Method and Revision Method Overview Special Parameters ASTM Method? Comments IP391/ o C diesel fuel petro/bio blends up to B-5 no backflush amino and/or cyano column no equivalent available at this time same as method EN12916:2006 MAH, DAH, Tri+AH reported IP548/ o C diesel fuel backflush required D MAH, DAH, Tri+AH reported amino and/or cyano column FAME interferes with result IP436/ o C aviation fuel, kerosene no backflush amino and/or cyano column D MAH and DAH reported not for samples with Tri+AH Page 4

5 General Conditions and Schematic of ASTM D 6591 Mobile phase: n-heptane at 1ml/min flow rate Column: Amino-propyl and/or Amino-Cyano-propyl bonded phases. Amino-propyl 4.6x250mm 5um is commonly used Column Temperature: approx o C Detection: Refractive Index Special Feature: 6 port valve for backflushing the column to elute tri+ aromatics as a single peak Page 5

6 General Schematic of ASTM D Figure 1, Agilent publication E Page 6

7 Recent HGA Method Updates: ASTM D Terms redefined more specific description of polyaromatics adopted Designate a new IP method correlation IP (used with ASTM D ) replaced by IP548/06 Exclusion or warning regarding Bio/Petrodiesel Blends the method recognizes difficulties with biodiesel fuel blends and refers the analyst to IP391/07 (EN12916:2006) for samples containing biodiesel (FAME) components due to inclusion of FAME components in the tri+ah backflush peak, erroneously high tri+ aromatic results are reported if D is used with biodiesel blends unusually high tri+ah results with this method should be investigated to determine if unsuspected FAME is present due to fuel contamination or mislabeling Page 7

8 General Conditions and Schematic of D System Performance Standard 1. cyclohexane 2. o-xylene (dimethylbenzene) 3. dibenzothiophene 4. 9-methyl anthracene ASTM D System Performance Std., Agilent p/n Mobile phase: n-heptane at 1ml/min flow rate Column: ZORBAX NH2 4.6x250mm, 5um Column Temperature: 20 o C Detection: Refractive Index, 35 o C Page 8

9 General Conditions and Schematic of D Calibration Standards 1. cyclohexane 2. o-xylene (1,2-dimethylbenzene) 3. 1-methyl-naphthalene 4. phenanthrene with backflush at ~9 min ASTM D Calibration Standard A-D, Agilent kit p/n Mobile phase: n-heptane at 1ml/min flow rate Column: ZORBAX NH2 4.6x250mm, 5um Column Temperature: 20 o C Detection: Refractive Index, 35 o C Page 9

10 Analysis of Petrodiesel, overlay of 3 injections 1. saturates 2. mono-aromatics 3. di-aromatics 4. tri+ aromatics t= <30 minutes Ultra Low Sulfur Diesel (ULSD), retail pump Page 10

11 Analysis of Petrodiesel, overlay of 3 brands 1. saturates 2. mono-aromatics 3. di-aromatics 4. tri+ aromatics t= <30 minutes Ultra Low Sulfur Diesel (ULSD), retail pumps a winter blend, old retained sample summer blends Page 11

12 ASTM D Separation Criteria The official method clearly describes the appearance and statistical evaluation of method conditions for the new revision Resolution, selectivity, precision and calibration linearity are clearly stated In the following slides we review the performance of the Agilent approach to this method. indicates that Agilent meets requirements

13 ASTM D Criteria Column Selection Column Descriptions: 4.6 x 250 mm, stainless steel column packed with 5um ZORBAX NH2 (p/n ) SPS 1. cyclohexane 2. o-xylene (1,2-dimethylbenzene) 3. dibenzothiophene 4. 9-methyl anthracene ml/min heptane 20C column temp. 35C RID temp. 20ul SPS no backflush. 6.4 Column System Any stainless steel HPLC column(s) packed with an approved amino-bonded (or polar amino/cyano-bonded) silica stationary phase is suitable

14 SPS Separation and Resolution Criteria SPS 1. cyclohexane 2. o-xylene (1,2-dimethylbenzene) 3. dibenzothiophene 4. 9-methyl anthracene ml/min heptane 20C column temp. 35C RID temp. 20ul SPS backflush 9.4 min provided it meets the resolution requirements laid down in Ensure that baseline separation is obtained between all components of the SPS. [without backflush]. 9.6 Calculate the backflush time, B, in seconds, using the following equation: B = ta + 0.4(tB ta)

15 Calculation of Resolution (Cyclohexane to 1,2 dimethylbenzene (o-xylene)) Ensure that the resolution between cyclohexane and 1,2 dimethylbenzene is not less than Column Resolution -- Calculate the resolution, R, between cyclohexane and 1,2 dimethylbenzene using the following equation. 2(t 2 -t 1 ) (difference in retention time) R = (y 1 +y 2 ) (averaging of peak widths). Name R. Time width (hh) Rsln. 1. cyclohexane ,2-dimethylbenzene) dibenzothiophene methyl anthracene

16 Linearity (section 9.4: R = >0.999, Intercept <0.01g/100ml) RID peak area vs. Std.Conc., o-xylene y = x R 2 = RID Peak Area Series1 Linear (Series1) Conc. (g/100 ml). correlation coefficients all >0.999 (fits are nominally 1), linear fit of the calibration points Intercepts all =<0.005g/100ml

17 Reproducibility for Retention and Area, Cal. A-D Calibrant A Analyte R.T. Avg., n=3 R.T. Stdev R.T.RSD% Area Avg., n=3 Area Stdev Area.RSD% xylene % 3.29E % 1-Me-naphthalene % 5.76E % phenanthrene % 7.12E % Calibrant B Analyte R.T. Avg., n=3 R.T. Stdev R.T.RSD% Area Avg., n=3 Area Stdev Area.RSD% xylene % 8.33E % 1-Me-naphthalene % 1.46E % phenanthrene % 3.55E % Calibrant C Analyte R.T. Avg., n=3 R.T. Stdev R.T.RSD% Area Avg., n=3 Area Stdev Area.RSD% xylene % 2.06E % 1-Me-naphthalene % 3.66E % phenanthrene % 8.87E % Calibrant D Analyte R.T. Avg., n=3 R.T. Stdev R.T.RSD% Area Avg., n=3 Area Stdev Area.RSD% xylene % 4.03E % 1-Me-naphthalene % 2.96E % phenanthrene % 1.76E % Average RSD% All Runs 0.028% 0.555%

18 Recommendations for the best configuration Agilent pump, minimum isocratic G1311A Agilent sampler, minimum G1329A Agilent thermostatted column compartment (TCC) with 6 port 2 position switching/backflush valve Agilent RID G1362A Agilent ChemStation B or EZChrom software, or third party compatible control/data software Agilent ZORBAX NH2 4.6x250mm 5um column equilibrated to heptane mobile phase Agilent calibrants for system performance and calibration HPLC grade n-heptane, 2-propanol Page 18

19 What to order, for consumables, ASTM D ASTM D (IP548/06) System Performance Standard (SPS) Agilent p/n ASTM D (IP548/06) System Calibration Solutions A-D Agilent p/n Column(s): ZORBAX NH2 4.6x250mm, 5um, Agilent p/n guard cartridge (pk/4) 4.6x12.5mm, 5um, Agilent p/n guard hardware (holder) kit, 4.6mm, Agilent p/n Normal phase pump seals, (pk/2), Agilent p/n Mobile phase: n-heptane, HPLC grade, minimum 4 Liter or 2.5 Liter bottles, 2-propanol, HPLC grade, 1 Liter (installation, maintenance) Page 19

20 Performance with Selected Samples Samples were collected from retail and commercial diesel and biodiesel distribution centers around the Chicago area One older sample was collected in the cold winter months, all others in recent warm summer months. Fuel blends vary seasonally in this area, with change occurring around early September and April Sample preparation: Accurately weigh ~1g fuel and dilute to 10ml with n-heptane. Mix thoroughly and inject 10ul. Calculations: Determine sample concentrations from calibration curves using 1,2 dimethylbenzene for MAH, 1-methyl-naphthalene for DAH and phenanthrene for Tri+AH. Correct for sample weight and dilution variables. Conditions: as described in previous slides Page 20

21 Analysis of Petrodiesel, overlay of 3 brands 1. saturates 2. mono-aromatics 3. di-aromatics 4. tri+ aromatics t= <30 minutes Ultra Low Sulfur Diesel (ULSD), retail pumps a winter blend, old retained sample summer blends Page 21

22 Analysis of Petrodiesel, n=3, Vendor 1 Group Avg., n=3 RSD% MAH g/100ml 0.68% DAH 4.74 g/100ml 2.77% Tri+AH 0.70 g/100ml 6.63% Vendor 1, Retail pump, summer MAH DAH Tri+AH Mobil Page 22

23 Analysis of Petrodiesel, n=3, Vendor 2 Group Avg., n=3 RSD% MAH g/100ml 0.12% DAH 5.10 g/100ml 0.60% Tri+AH 0.77 g/100ml 1.52% Vendor 2, Retail pump, summer MAH DAH Tri+AH Marathon Page 23

24 Analysis of BioPetrodiesel with ASTM D Amount units Group g/100ml MAH 4.12 g/100ml DAH 3.59 g/100ml Tri+AH Vendor 3, consumer retail pump, summer, dispensing pump labeled diesel erroneous high Tri+AH due to FAME in sample Citgo Page 24

25 Analysis of BioPetrodiesel with ASTM D Amount units Group g/100ml MAH 5.12 g/100ml DAH 4.12 g/100ml Tri+AH Vendor 4, commercial biodiesel blend, dispensing pump labeled diesel erroneous high Tri+AH due to FAME in sample RR Page 25

26 Analysis of Biodiesel B-11 with Method IP391/07 Group Avg., n=3 RSD% MAH g/100ml 5.06% DAH 5.15 g/100ml 3.38% Tri+AH 0.72 g/100ml 4.58% Vendor 4, ULSD-based biodiesel blend retail auto/light truck Results are n=3 by IP391/07 method approved for diesel and biodiesel blends Tri+AH region FAME resolved RR Page 26

27 ASTM D Observations The method retention time stability is very sensitive to column activity, as noted in the official method. This is typical for many normal phase separation methods Moisture in solvents or samples is problematic and affects column activity Variable retention is primarily due to moisture and temperature, though good system maintenance is essential Use of normal phase seals in the pump is very important Page 27

28 Summary ASTM D Status Specialized all-agilent column arrangement meets SPS resolution requirements for cyclohexane and 1,2-dimethylbenzene (o-xylene) Adding the 6-port valve to the system configuration is required, however it is possible to easily switch between current IP391/07 (no backflush, for biodiesel blends) and ASTM D 6591 (with backflush, no FAME content) Page 28

29 References 1. IP391/07 / EN12916:2006, Energy Institute, UK 2. Agilent application note E 3. ASTM Methods D , D Page 29

30 Appendix and supplemental slides may be used depending on audience and need. Page 30

31 Acknowledgements Cynthia guidance, resources and encouragement Maggie continued technical support and for persistence in keeping this development on the road map Melanie/Georgia/Phil standards packaging and work with the Ultra Scientific team Andre creating the opportunity and motivation Ultra Scientific too many to name, once again committed to a successful development with Agilent Page 31