A sample injection subsystem of a high pressure liquid chromatography system for introducing a sample for analysis by the high pressure liquid chromatography system, the sample injection subsystem comprising: a rotary shear-seal injection valve (302, 402, 502) having a valve stator (303, 403, 503) and a valve rotor (301, 401, 501), the valve stator (303, 403, 503) having a sample needle port (308, 408, 508), a downstream loop port (316, 416, 516) of an external sample loop, a separation column port (306, 406, 506), a pump port (326, 426, 526), an upstream loop port (314, 414, 514) of the external sample loop, and a syringe port (310, 410, 510), wherein the pump port (326, 426, 526) has a pump port channel (330, 430, 530) extending toward the separation column port (306, 406, 506), the valve rotor (301, 401, 501) rotatably abutting said valve stator (303, 403, 503) and having a sample channel (318, 418, 518), a column channel (324, 424, 524) and a column channel extension (332, 432, 532) extending toward a loop channel (320, 420, 520), wherein in a load state of the rotary shear-seal injection valve (302, 402, 502), the sample channel (318, 418, 518) establishes a connectivity between the sample needle port (308, 408, 508) and the downstream loop port (316, 416, 516) of the external sample loop, the upstream loop port (314, 414, 514) of the external sample loop is connected to the syringe port (310, 410, 510) via the loop channel (320, 420, 520) extending beyond the syringe port (310, 410, 510) toward the sample channel (318, 418, 518), and the pump port (326, 426, 526) is in a direct communication with the separation column port (306, 406, 506) via the column channel (324, 424, 524) overlapping the pump port (306, 406, 506), wherein in an injection state of the rotary shear-seal injection valve (302, 402, 502), the valve rotor (301, 401, 501) having established a communication between the pump port (326, 426, 526) and the separation column port (306, 406, 506) via the external sample loop by connecting the pump port (326, 426, 526) with the upstream loop port (314, 414, 514) via the loop channel (320, 420, 520) and by connecting the separation column port (306, 406, 506) with the downstream loop port (316, 416, 516) via the column channel (324, 424, 524), is in an orientation that terminates the direct communication between the pump port (326, 426, 526) and the separation column port (306, 406, 506) via the column channel extension (332, 432, 532) and the pump port channel (330, 430, 530), and the syringe port (310, 410, 510) is in communication with the sample needle port (308, 408, 508) via the sample channel (318, 418, 518). a rotary shear-seal injection valve (302, 402, 502) having a valve stator (303, 403, 503) and a valve rotor (301, 401, 501), the valve stator (303, 403, 503) having a sample needle port (308, 408, 508), a downstream loop port (316, 416, 516) of an external sample loop, a separation column port (306, 406, 506), a pump port (326, 426, 526), an upstream loop port (314, 414, 514) of the external sample loop, and a syringe port (310, 410, 510), wherein the pump port (326, 426, 526) has a pump port channel (330, 430, 530) extending toward the separation column port (306, 406, 506), the valve rotor (301, 401, 501) rotatably abutting said valve stator (303, 403, 503) and having a sample channel (318, 418, 518), a column channel (324, 424, 524) and a column channel extension (332, 432, 532) extending toward a loop channel (320, 420, 520), wherein in a load state of the rotary shear-seal injection valve (302, 402, 502), the sample channel (318, 418, 518) establishes a connectivity between the sample needle port (308, 408, 508) and the downstream loop port (316, 416, 516) of the external sample loop, the upstream loop port (314, 414, 514) of the external sample loop is connected to the syringe port (310, 410, 510) via the loop channel (320, 420, 520) extending beyond the syringe port (310, 410, 510) toward the sample channel (318, 418, 518), and the pump port (326, 426, 526) is in a direct communication with the separation column port (306, 406, 506) via the column channel (324, 424, 524) overlapping the pump port (306, 406, 506), wherein in an injection state of the rotary shear-seal injection valve (302, 402, 502), the valve rotor (301, 401, 501) having established a communication between the pump port (326, 426, 526) and the separation column port (306, 406, 506) via the external sample loop by connecting the pump port (326, 426, 526) with the upstream loop port (314, 414, 514) via the loop channel (320, 420, 520) and by connecting the separation column port (306, 406, 506) with the downstream loop port (316, 416, 516) via the column channel (324, 424, 524), is in an orientation that terminates the direct communication between the pump port (326, 426, 526) and the separation column port (306, 406, 506) via the column channel extension (332, 432, 532) and the pump port channel (330, 430, 530), and the syringe port (310, 410, 510) is in communication with the sample needle port (308, 408, 508) via the sample channel (318, 418, 518).