Not Just for Paint Chips Anymore High Throughput, Open Vessel Microwave Digestion of Matrices Requiring Moderate Conditions
Objective Develop a sample preparation procedure for analysis of a range of sample types Meet laboratory needs for increased throughput and turn around time Development of a safe, inexpensive, disposable microwave vessel system
A Novel Microwave Approach to a Difficult Problem Instrumentation CEM MDS/MARS Microwave Digestion System Fiberoptic Temperature Control CEM DV-50 High Throughput Vessel Set (P/N 430420) *Turntable adapter must be used in the MARS.
DV-50 Vessel
DV-50 Vessel Accessory Set Specifications Sample Capacity: 1-36 vessels Vessel: open disposable 50 ml centrifuge tube Operating temperature: 115 C
DV-50 Vessel Accessory Set 52 Vessel Turntable
Sample Types Paint Chips - ELPAT ** Round 010 Soils - ELPAT ** Round 010 Wipes - ELPAT ** Round 010 ** Environmental Lead Proficiency Analytical Testing Reference MaterialM
Procedure Weigh sample directly into DV-50 tube * Add nitric acid ** Heat at 115 C C for 15-30 min. *** Allow to cool Dilute to the 50 ml mark with DI water Shake Centrifuge Aspirate directly into ICP or AA * paint chips (0.1 g), soils (0.1 g) ** paint chips (5 ml), soils (10 ml) *** paint chips (15 min.), soils (30 min.)
ELPAT Paint Chip Lead Recoveries DV 50 Lead Values Certificate Lead Values Range Sample ID Mean * % RSD Low High % RSD (Wt. %) (Wt. %) (Wt. %) Sample 1 0.1020 1.82 0.0875 0.1312 6.7 Sample 2 1.0089 4.25 0.7310 1.1843 7.9 Sample 3 3.4052 4.52 2.8367 4.3141 6.9 Sample 4 0.5449 4.43 0.4525 0.6730 6.5 * 36 digestions
ELPAT Soil Lead Recoveries DV 50 Lead Values Certificate Lead Values Range Sample ID Mean * % RSD Low High % RSD (Wt. %) (Wt. %) (Wt. %) Sample 1 416.6 4.6 328.9 518.8 7.5 Sample 2 1493.9 4.1 1190 1845 7.2 Sample 3 192.3 5.2 151.1 240.8 7.6 Sample 4 768.4 5.4 649.3 918.1 5.7 * 36 digestions
ELPAT Wipe Lead Recoveries Sample ID Wipe 1 Wipe 2 Wipe 3 Wipe 4 Wipe 5 Wipe 6 DV 50 Lead Results Lead Value (ppm) 235 60.8 845 484 103 433 Certificate Lead Values Certified Lead Value (ppm) 237 69.5 870 472 108 479 Range Low High 188 47.8 624 351 84.0 377 285 91.2 1115 592 133 581
DV 50 50 ml High Throughput Vessel with filter basket
Baby Wipes Procedure Place wipe into DV-50 tube Spike with 100uL of 1000 ug/ml Pb standard Add 10 ml HNO 3 and place basket into vessel Heat at 110 C for 20 minutes Cool and remove basket Dilute to 50 ml and filter. Analyze by ICP
Baby Wipes Lead Spike Recoveries n Spike Recovery RSD ug/ml % % 19 1.98 99 1.79
Mining Industry Huge batches of samples for metals assessment 4 to 6 hours digestion time per batch Several hundred per day Throughput - a major problem! Microwave technology typically not used Microwave samples usually prepared in batches of 12 or less
Application - Sulfide Ore For Analysis of Ag, Ba, Cu, Fe, Pb, and Zn Zinc Concentrate Lead Concentrate Feed Bulk Feed Run of Mine
Initial Procedure Weigh 0.1g of sample into DV-50 centrifuge tube Add 10 ml HNO 3 Load onto 36-position turntable Insert temperature probe into reference vessel Heat using Microwave method
Sulfide Ore Heating Program Stage 1 2 3 Power (%) 75 50 50 Temp (oc( oc) 100 110 115 Max Time (min) 15 15 15 Hold Time (min) 1 5 10
Final Procedures Cool samples and dilute to 50 ml mark Mix well and centrifuge to settle any solids Analyze directly from 50 ml tube by ICP
Feed Recoveries DV-50 Ag Ba Cu Fe Pb Zn ppm wt % wt % wt % wt % wt % 50 Avg. 466 1.98 0.452 14.0 3.66 8.48 Std. Dev. 26.9 0.043 0.019 0.172 0.83 0.233 Hot Plate Avg. Avg. 461 1.20 0.345 10.7 2.77 6.64 Std. Dev. 23.8 0.033 0.011 0.154 0.078 0.194
Zinc Concentrate Recoveries DV-50 Ag Ba Cu Fe Pb Zn ppm wt % wt % wt % wt % wt % 50 Avg. 958 0.349 0.722 5.33 3.93 49.9 Std. Dev. 34.3 0.038 0.024 0.102 0.062 0.645 Hot Plate Avg. Avg. 948 0.279 0.715 5.37 4.05 50.7 Std. Dev. 37.1 0.004 0.021 0.101 0.124 1.36
Lead Concentrate Recoveries DV-50 Ag Ba Cu Fe Pb Zn ppm wt % wt % wt % wt % wt % 50 Avg. 4582 0.174 2.09 7.13 49.9 12.0 Std. Dev. 145 0.037 0.050 0.466 0.313 0.218 Hot Plate Avg. Avg. 4580 0.179 2.04 6.90 51.8 12.5 Std. Dev. 357 0.007 0.158 0.648 4.91 1.20
Tissue Procedure Weigh 0.2g sample into DV-50 tube Add 5 ml of nitric acid Cap and let sit overnight Heat at 115 C C for 55 minutes Allow to cool Dilute to the 20 ml mark with DI water Vortex and dilute further for analysis as needed Aspirate directly into ICP or AA
NIST SRM Biological Tissue Lead Recoveries DV 50 SRM Certificate Mean Low High Mean Low High ug/g ug/g ug/g ug/g ug/g ug/g Oyster Tissue 0.4 0.32 0.46 0.371 0.357 0.385 Bovine Muscle 0.37 0.27 0.45 0.38 0.14 0.62 n = 10
NIST SRM Biological Tissue Lead Recoveries DV 50 SRM Certificate Mean Low High Mean Low High ug/g ug/g ug/g ug/g ug/g ug/g Oyster Tissue 5.16 4.68 5.55 4.15 3.77 4.53 Bovine Muscle 0.013 0.011 0.017 0.013 0.002 0.024 Bovine Liver 0.56 0.52 0.59 0.50 0.47 0.53 n = 10
Blood Procedure Weigh 0.5 g of blood into DV-50 tube Add 4 ml of nitric acid and cap Heat at 115 C C for 30 minutes Add 0.8 ml of 50%H202 Heat at 115 C C for 8 minutes Dilute to 25 ml with DI water Aspirate directly into ICP-MS for 17 elements including Hg
Element UTAK Blood (Mid Range) Element Recoveries MDL DV 50 RSD Certificate ug/g ug/g % ug/g Ca 20 41 9 38 Cd 0.001 0.016 3.9 0.015 Hg 0.004 0.024 4 0.032 Mg 3 36.9 3.1 36.3 Pb 0.003 0.092 4.4 0.09 Zn 0.3 5.4 3.2 5.11 Data Courtesy of Doctor s s Data Inc., W. Chicago, IL
Element UTAK Blood (High Range) Element Recoveries MDL DV 50 RSD Certificate ug/g ug/g % ug/g Ca 20 57.2 9 60 Cd 0.001 0.051 3.9 0.049 Hg 0.004 0.040 4 0.057 Mg 3 48.1 3.1 44.1 Pb 0.003 0.269 4.4 0.270 Zn 0.3 7.8 3.2 7.1 Data Courtesy of Doctor s s Data Inc., W. Chicago, IL
Hair Procedure Place 0.2 g of cut, washed hair into DV-50 tube Add 3 ml of nitric acid and cap Heat at 115 C C for 30 minutes Dilute to the 50 ml mark with DI water Aspirate directly into ICP-MS for 42 elements including Hg, As and Se
China Certified Reference Material Element Element Recoveries MDL DV 50 RSD Certificate ug/g ug/g % ug/g Al 1 9.2 8.6 60 As 0.02 0.78 7.1 0.59 Cd 0.02 0.091 9.4 0.095 Cr 0.04 2.88 13 4.77 Hg 0.07 2.18 8.5 2.16 Pb 0.2 7.77 4.5 7.2 Se 0.8 0.61 7.2 0.58 Zn 6 192 3.3 189 Data Courtesy of Doctor s s Data Inc., W. Chicago, IL
Conclusions Fast, high throughput procedure Vessels can be disposed after use Recoveries agree with reference values Future experiments: 120-position turntable for 15 ml centrifuge tubes