Methods and apparatus for automated on-column injection using a slender needle
First Claim
1. A system for performing on-column injection of a sample into a chromatographic device, comprising:
- a syringe;
a hollow needle connected to the syringe for passage of the sample therethrough, the needle having a base portion and an end portion, the end portion having an outside diameter less than that of the base portion; and
a needle support having a bore therethrough, the diameter of said bore being sufficient to enclose and thereby restrict the deflection of at least one of said base portion and end portion so enclosed to less than a predetermined maximum deflection ym ; and
a positioning mechanism operatively connected to the needle and the needle support for effecting automated relative axial movement of the needle with respect to the needle support, said movement being between a first position wherein the end portion of the needle is substantially enclosed within the needle support, and a second position wherein the end portion is extended substantially outside the needle support.
2 Assignments
0 Petitions
Accused Products
Abstract
Methods and apparatus for preventing the failure of slender syringe needles used for on column injection in gas chromatographs are disclosed. A needle holder designed to support the needle precludes bucking deflection beyond the maximum allowable value. In a preferred embodiment, the needle used is a tapered needle that has a proximal diameter and a distal diameter that is smaller that the proximal diameter. In these embodiments, the diameter of the bore through the needle holder is slightly larger than the proximal diameter to permit the full insertion of the entire needle structure. The needle holder bore diameter is sufficiently small, however, to preclude catastrophic failure due to buckling.
30 Citations
6 Claims
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1. A system for performing on-column injection of a sample into a chromatographic device, comprising:
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a syringe; a hollow needle connected to the syringe for passage of the sample therethrough, the needle having a base portion and an end portion, the end portion having an outside diameter less than that of the base portion; and a needle support having a bore therethrough, the diameter of said bore being sufficient to enclose and thereby restrict the deflection of at least one of said base portion and end portion so enclosed to less than a predetermined maximum deflection ym ; and a positioning mechanism operatively connected to the needle and the needle support for effecting automated relative axial movement of the needle with respect to the needle support, said movement being between a first position wherein the end portion of the needle is substantially enclosed within the needle support, and a second position wherein the end portion is extended substantially outside the needle support. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification