Table XI

Extracted Elemental Impurities Reported for Rubber Elastomers (RE)

ElementConcentration (mg/kg unless noted)Extraction DetailsCommentsRef.
SolventConditions
AlNR1–10Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NR–1.7High pH (≈9)
NREthanol/water
0.66pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
3.6pH 9.5
<100 ng/mLAqueous solventsRubber closures, 121 °C for 30 minLeaching was constant across solvents45
1300–5000 ng/mL0.5% chelatorsRubber closures, 121 °C for 30 minChelators included EDTA, nitrilotriacetic acid (NTA), oxalic acid45
<100–1200 ng/mL0.5% amino acid solutionsRubber closures, 121 °C for 30 minHighest Al leaching in proline, arginine solutions45
BNR–13Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NR–23High pH (≈9)
NR–23Ethanol/water
BaNRLow pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NRHigh pH (≈9)
NREthanol/water
49pH 2–12Sealed vessel, 121 °C for 1 h, 0.07 g sample/mL solvent6 materials; plungers, highest value440
<0.01pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
<0.01pH 9.5
Br18pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
21pH 9.5
CaNR–7.1Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NR–3.7High pH (≈9)
NR–4.7Ethanol/water
8.6pH 2–12Sealed vessel, 121 °C for 1 h, 0.07 g sample/mL solvent6 materials; plungers, highest value440
4.1pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
2.1pH 9.5
Cr0.01pH 2.5Sealed vessel, 121° for 1 h, 0.025 g sample/mL solventStrip535
0.01pH 9.5
FeNR–0.95Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NRHigh pH (≈9)
NREthanol/water
0.33pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
0.08pH 9.5
K<0.1pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
6.8pH 9.5
MgNR–23Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NR–7.5High pH (≈9)
NR–32Ethanol/water
20pH 2–12Sealed vessel, 121 °C for 1 h, 0.07 g sample/mL solvent6 materials; plungers, highest value440
3.5pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
2.9pH 9.5
Mn0.01pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
<0.01pH 9.5
NaNR–24Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NAHigh pH (≈9)
NR–18Ethanol/water
3.1pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
Ni0.01pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
0.01pH 9.5
PNRLow pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NA2High pH (≈9)
NREthanol/water
SNR–57Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NR–1430High pH (≈9)
NR–210Ethanol/water
SiNR–47Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NR–1000High pH (≈9)
NR–120Ethanol/water
0.10pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
0.25pH 9.5
Sr1.0pH 2–12Sealed vessel, 121 °C for 1 h, 0.07 g sample/100 mL solvent6 materials; plungers, highest value440
0.01pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
0.01pH 9.5
Ti0.29pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
<0.1pH 9.5
V0.01pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
0.01pH 9.5
ZnNR–515Low pH (≈3)Sealed vessel, 55 °C for 4 days, 0.04–0.30 g sample/mL solvent22 materials tested; stoppers, parts312
NR–26High pH (≈9)
NR–75Ethanol/water
35pH 2–12Sealed vessel, 121 °C for 1 h, 0.07 g sample/100 mL solvent6 materials; plungers, highest value440
2.9pH 2.5Sealed vessel, 121 °C for 1 h, 0.025 g sample/mL solventStrip535
0.5pH 9.5
Zr<0.1pH 2–12Sealed vessel, 121 °C for 1 h, 0.07 g sample/mL solvent6 materials; plungers, highest value440

  • Notes:

  • ↵1 NR = Not reported: not extracted at reportable levels (generally less than 0.01 μg/g).

  • ↵2 NA = Not applicable; element was a component of the extracting solvent.

  • ↵3 Elements that were not extracted in reportable levels included Ag, As, Be, Bi, Cd, Co, Cr, Cu, Ge, Li, Mn, Mo, Ni, Pb, Sb, Se, Sn, Sr, Ti, V and Zr.

  • ↵4 Elements that were not extracted in reportable levels, generally 1 μg/g, included Ag, As, Bi, Co, Cr, Cu, Mo, Ni, Sb, Se, Sn, and V.

  • ↵5 Elements that were not extracted in reportable levels, generally 0.01 μg/g, included As, Co, Cu, Mo, Pb, Ni, and Sb.