Common problems occurred in the use of HPLC columns HPLC column is the “HEART” of the chromatographic system. Due to the wide variety of samples and the complex matrix of the sample, HPLC column is easily contaminated by strong retained substances. These strongly retained substances are usually difficult to elute. Read more…
Dear Customers, Please be informed that recently some of our customers may have received mails from info@welchmat.com requesting payment related details(as shown below), which is confirmed to be a Fake mail address! The REAL info@welchmat.com address is working normally and we definitely do not send any mails or requests to customer by this Read more…
C18 is retentive to non-polar compounds as the non-polarity of C18 group, but for polar compounds, sometimes the mobile phase with high water ratio should be used to make the analyte retained on the column. However, under this condition for a long time, phase collapse will occur on conventional C18, Read more…
It’s usually very difficult to identify the twins, but mothers can easily identify their twins according to habits and characteristics. Isomer In Chemical world, there also exist some compounds with similar structure and properties like isomer and enantiomer. It’s very hard to operate chromatography separation on these compounds, for example, Read more…
Isomers are compounds with similar structures and their chemical equilibrium constant(K) is almost the same. It’s very difficult to operate chromatography separation on isomers, especially the separation of meta and para isomers on the benzene ring. Usually, we would choose HPLC columns with steric hindrance to analysis, such as Ultisil XS-C18, Ultisil PFP, Ultisil Read more…
The 19th CPhI China was held on 18th June, 2019 and it lasted three days. It’s the ninth time for Welch to attend CPhI China. Welch has obtained great progress in the past nine years and Welch showed all series of products through a huge booth this time. Welch is one of Read more…
CPhI China 2019 will be hold from 18th-20th June, 2019 at Shanghai New International Expo Centre. Why CPhI？ CPhI China 2019 is the gateway to successfully grow business at the 2nd largest pharma market in the world. Together with P-MEC China which focuses on pharmaceutical machinery and equipment, CPhI China is your Read more…
We are pleased to announce that our headquarter will be relocated to the following address as of June 5, 2019: Building 10, Zijing Park, Tus-Caohejing Science Park, No. 85 Mingnan Road, Songjiang District, Shanghai 201613 CHINA We are pleased to announce that our headquarter will be relocated to the following address as of June Read more…
Oxygen is a hazardous substance for most of the capillary columns. At room temperature, the column will not be damaged. But as the column temperature increases, the column will be severely damaged. It is important to be noted that polar GC columns will be severely damaged at low oxygen concentrations. Part.1 Apparent phenomena of oxidative damage and influence on analysis ● Influence on column efficiency The Read more…
Superior core-shell column There are mainly two kinds of chromatographic packing materials: silica gel and polymer. Their structural difference makes maintenance and separation results different. Silica based packing materials contain fully porous silica, ethyl bridged hybrid silica, monolithic silica and core-shell silica. Ultra-efficient analytical results of UHPLC can be obtained on a HPLC instrument with a core-shell Read more…