Are you convinced that your glass vial is really inert and releases every trace of compound you put in it for further analysis?
An instrument -- whether it is an LC or a GC -- will only detect what goes into the detector, so if you have a limited amount of sample and your request is to detect low levels, then you need to consider the type of glass vial you’re using. This is true for every analysis since this begins with how you get the sample into your system (your vials or plates).Did you know that there are significant differences in hydrolytic glass?
When we talk about glass types 70, 51, or 33, the number indicates the amount of free silanol groups on the surface of your glass. Free silanol groups tend to interact with polar substances such as NH, NH2 or OH groups (drugs of abuse: non-derivetized), and with halogenated species (PCBs, Fuarans and Dioxins). They also interact with pesticides containing sulfur or phosphor in the molecular structure – to name merely a few examples. Derivatization or salinized glass vials -- which can show weird effects in LCMS -- are not always an option. This might not matter if you are looking into the percentage of analytes. However, when talking about femtogram, this becomes a different story. If you are missing the last points in your lower end of the calibration curve, then you have your answer.
Considering a lack of awareness on this topic, the sensitivity of the instrument is of paramount importance, considering something as trivial as the vials could make or break your detection. If you see issues with your detection limits, consider the vials you use. If the analyte doesn’t reach your detector, it can’t be detected. It as simple as that.
On the topic of glass quality: Have you ever heard about Chromcol GOLD vials? These ultra-inert vials with the lowest free silanol groups on the surface are an excellent solution to your analytical challenges.Improve your detection limits down to the last femtograms: www.thermofisher.com/inertvials