microFAST Isotope – Dual Loop Syringe Loading & Injection

The microFAST Isotope utilizes a syringes to precisely load micro-volumes samples (as low as 5 µL) and inject them at any user defined flow rate. The figures below illustrate the capability to produce smooth injection profiles for 5 µL samples at 100 µL/min with excellent reproducibility (<2% RSD, n=10).

5 µL Injection at 100 µL/min

10 Replicates of 5 µL Injections at 100 µL/min

The microFAST Isotope precisely syringe injects micro-volume samples (5 µL) into the Apex Omega at 5 µL/min, 10 µL/min and 20 µL/min. The figures below plot signal profiles of approximately 60 sec, 30 sec and 15 sec for a 5 µl sample. Increased sensitivity with flow rate is a result of high sample transport efficiency using the Apex Omega. Smooth injection profiles for 5 µL samples at all flow rates, results in excellent reproducibility (<2% RSD, n=5).

5 µL Injections at 5, 10, and 20 µL/min with Apex Omega

5 µL Injections at 5, 10, and 20 µL/min with Apex Omega

Li isotope ratios are measured using the microFAST Isotope system. Syringe injecting 100 μL of sample at 20 μL/min provides nearly 5 minutes of steady state signal for isotope ratio analysis. External reproducibility is improved for the smallest absolute sample amounts (6 ng) using low volume solution aliquots.

Syringe Loading & Injection

δ7Li (6.3 ng Li per quintuplicate)

Minimizing the amount of Nd required to obtain desired precision (>50 ppm) and throughput for precious oceanographic samples is illustrated in two figures. First, internal precision is for plotted for variable amounts of Nd injected at 100 µL/min for two minutes. Less than 50 ppm (2 RSD) internal precision is obtained for 2 ng samples of Nd. Repeat analysis of reference materials JNdi and La Jolla indicate that the external precision for 2 ng of Nd is similar to the 50 ppm internal precision and appropriate for oceanographic applications.

Sample Amount

Reproducibility for 2 ng