In high-performance liquid chromatography (HPLC), minimising dead volume is critical to achieving accurate, reproducible results. Dead volume refers to the extra space in the flow path that can trap and retain sample, leading to carryover and poor peak shape.
A key area where dead volume can accumulate is in the HPLC autosampler vial. The space between the bottom of the vial and the sampling needle can create a pocket where sample can become trapped. This is particularly problematic when working with small sample volumes, as even a tiny amount of unrecovered sample can significantly affect your results.
This is where vial inserts come in. Vial inserts are small accessories that fit into standard HPLC vials to reduce the overall volume. By minimising headspace, vial inserts help to eliminate dead volume and improve sample transfer.
Let’s take a closer look at how vial inserts can optimise HPLC workflows:
By reducing the gap between the vial bottom and the needle, vial inserts allow the autosampler to access more of the sample. This increases the amount of analyte injected, resulting in better detection limits and more reliable quantification. Even a small increase in sample recovery can make a big difference, especially for trace analytes or valuable samples.
The reduced dead volume of the vial inserts means that less sample is left in the flow path after injection. This minimises the risk of carryover contaminating subsequent runs, which is particularly important for trace-level analyses or when switching between very different sample matrices.
By eliminating extra volume in the vial, vial inserts promote better peak shape and resolution. Sharper, more symmetrical peaks allow more accurate integration and quantification of target compounds. This can be particularly beneficial when separating narrowly eluting analytes or improving the limit of detection.
Vial inserts are particularly useful when working with very small sample volumes, such as in bioanalysis or high throughput screening. The insert allows you to analyse micro-scale samples without losing valuable material to dead volume. This helps to maximise the information you can gain from limited sample volumes.
When selecting vial inserts, it is important to choose a design that is compatible with your specific HPLC vials and autosampler. Many manufacturers offer inserts in a variety of materials, volumes and shapes to fit a wide range of system configurations. Taking the time to find the right vial insert can pay dividends in terms of improved data quality and instrument performance.
Incorporating vial inserts into your HPLC workflow is an easy way to minimise dead volume and optimise sample transfer. By reducing carryover and improving peak quality, vial inserts can help you generate more reliable, higher quality data from your HPLC analyses.