I do not understand your question. HPLC and "Methods" are two different things. We create HPLC "Methods for use in chromatography. It does not matter if they are for use on a Prep or Analytical system as they are still called methods.

If you need an analytical HPLC (for 99.95% of most applications) for routine analysis and method development (flow rates 0.010 to 10 ml/min), then for best result use or purchase an analytical HPLC. IOW: Please do not purchase a " Waters delta prep" LC system when your actual need is completely different.

Flow rate ranges are just one of many differences between Analytical (~ less than 5 mL/Min) and Preparative chromatography (> 20 mL/min). Prep HPLC systems have pump heads with huge internal dwell volumes (to pump very large amounts of liquid), use very large internal diameter tubing, much larger columns with large internal volumes and are biased toward high flow rate use, from 20 ml/min to several hundred mLs or even liters / min. While some companies do/did offer combo Prep systems which could be used for semi-prep and even some analytical runs (e.g. Delta Prep 4000 system), they were poorly suited for real analytical purposes. The large dwell volume of the Prep heads and large ID tubing means huge gradient delays and diluted samples. The associated Injector and detector modules are also inappropriate for use with analytical applications. *Hybrid systems which allowed users to swap the prep heads for analytical ones still had to change out all of the tubing, loops and detector's flow cell too. Prep and Analytical HPLC system are very different systems with different needs and hardware.  Prep systems can also be equipped with many of the same features and modules (i.e. Column Heaters, AutoInjectors, UV/VIS Detectors, Fraction Collectors) as analytical systems, but again, they are for very different purposes (Prep are for separating, fractionating and purifying large amounts of material; Analytical systems are for developing methods to separate and quantify small amounts of material). Under normal operations, a Prep system is used with an analytical system to check purity of fractions. Only buy/use a Prep system if you need those capabilities and please do not buy/use a Pre HPLC system if your main application is an analytical one.

You wrote: "I've heard Prep HPLC has limitation of sensitivity." This statement does not make any sense. In Prep LC, you normally have huge amounts of sample so you are intentionally reducing the detector sensitivity in most methods so it does not saturate the detector. Sample quantity, chemical properties (e.g. strong or weak chromophore?),detection method used and quality of method used determine sensitivity for all methods on any type of HPLC system.

Summary: We do not recommend using a "Preparative HPLC" system for analytical HPLC methods. Prep HPLC systems have huge dwell volumes which are incompatible with the low flow rates and small columns used in analytical gradient HPLC.

• Mona Shahgholi wrote: " If you can stably achieved flow rates for analytical columns then it should be fine".

**The above response is incorrect and misleading. Flow rate stability has little to do with the applicability of using a PREP HPLC system for an analytical HPLC application. The delay volume of most Prep HPLC system is enormous, so use with analytical scale columns, injection volumes, detector flow cells and analytical gradient delay volumes may make it unusable. As noted earlier, there are many parameters which need to be addressed to answer such a broad question. Please consult the help of an experienced chromatographer for such matters.

Dear Dr Seongho Jeon,

Could you please explain your question again? Probably me or someone else can help.

Best regards

Aly

My question is simply, Can I use prep HPLC as just HPLC?

typical HPLC system, I mean, pumping like low rate(0~1ml/min) and high pressure (~1000psi), heating column(~60~70oC), and data from UV or RID detector)

If I understand correctly whether on not you can use a prep HPLC for analytical work depends on your particular instrument.  If you can stably achieved flow rates for analytical columns then it should be fine.

Dear Seongho,

yes you can use prep HPLC for analytical works.

BUT you have to remember that in chromatography all dead volumes are fundamentals (for gradient elution and for resolution) and must be reduced in order to maximize the resolution. Additionally also the detector dead volume is important for the same reason.

For your applications you can check the back-pressure. In HPLC with analytical column. Generally the prep HPLC support the back-pressure (check the manual before) generally observed in HPLC (approx. 1000 to 2000 psi).

Sonu Kumawat: When you have a new question, please create a NEW Topic Thread on RG, and do not use someone else's (please post a new question under your account). Please do not hijack another person's post (especially one that is 4 years old). to add your question (follow proper forum etiquette and guidelines). Please DELETE your post and repost it as a new question.

In the meantime, here is some info for you:

• Note: The "LC-100" HPLC system is an academic grade HPLC rated for analytical use. If you goal is to collect large fractions of compounds to submit for further analysis using other analytical techniques (NMR, FTIR, or even HPLC), then you should consider using a PREPARATIVE HPLC with preparative or semi-preparative HPLC columns to collect enough fractions. *No other advice on this matter can be provided until you provide a detailed method with results to know how to proceed.
• Maximum Sample Load: To determine the maximum sample load for YOUR HPLC Method and Column, you will have to conduct a "Loading Study". In simple terms, this is done to determine the maximum amount of sample which can be loaded onto the column AND still provide the required resolution needed. As you have no HPLC experience at this time, please contact someone at your school who is experienced in chromatography to assist you in-person. It takes many years to learn the basics of HPLC.

Seongho,

No! Generally, a Prep HPLC has a larger tubing size, accepts a thicker column size, uses a larger injection size, and a less sensitive detector. This means even if you use the same chromatographic method you will obtain a MUCH higher LOQ and in some cases a molecule of interest that even doesn't appear above the baseline (not detectable).