Metal loops will often absorb sample components resulting in inaccurate quantitative results. In addition, metal loops may be corroded by high-salt buffers and chloride salts. Sample Loops are made from PEEK tubing and fittings. PEEK (Poly-Ether-Ether-Ketone) is a mechanically strong, chemically inert polymer ideal for HPLC applications where metal surfaces may interact with mobile phase or sample components.
Each Sample Loop is supplied with two PEEK hex-head nuts and ferrules. These fittings grip the tubing in two locations for a more reliable connection. Rheodyne Sample Loops are made of natural PEEK. This means no dye leaching into your sample. Like metal loops, the size designations of PEEK loops are nominal. The actual volumes can differ from the theoretical resignations because of the ± 0.05 mm (0.002") tolerance of the tubing bore. Accuracy of large PEEK loops (0.8 mm, 0.030" bore) is about ±14%, intermediate loops (0.5 mm, 0.020") ±21%, and small loops (0.2 mm, 0.007") ±65%. Bore: 0.18 mm