2011-06-29 (Wed) 04:13:35 Shodex Technical question

Record: 308

---

Category: Specifications Product: KS-801 Sample: Sorghum, sweet potato and napier grass

---

Question We have problems with pressure changes, it can change 10 kgf in one day. The maintenance of equipment has already been done and we want to know if it can be something related to the samples. Pretreatment of samples consists in precipitation of proteins and filtration through 0.2μm filters. Is neccessary another kind of treatment?     Answer We estimate the target compounds are extracted by H2O. If any organic solution is used for the extraction, please confirm the solubility of the sample solution into H2O. And we estimate there is any clogging at the inlet of KS-G. Could you please confirm the pressure of KS-G and KS-801 individually? If the pressure of KS-801 with the following condition is around 20 kgf/cm^2, KS-801 does not have any pressure trouble, and KS-G is clogged. Eluent : H20 Flow rate : 1.0mL/min Column temp.: 50deg-C In this case, please set KS-G up side down on the flow line of HPLC system, and run H2O at 0.2mL/min. Do not connect KS-G with any detector not to run the clogging through the flow line. If the clogging is removed, the pressure should be decreased. And if this procedure is effective, any matrix was run trough the column from the injector or the eluent. Please confirm when the pressure rising was observed. If the pressure was risen during the running H2O, the clogging in the flow line might come into the column. If the pressure was risen at the each injection, the solubility of the sample solution and the eluent may be not good.     Additional Comments