REVERSED - 186 Annonces

Friday 20 September 2019

Solid phase extraction is essentially a liquid chromatographic separation. The main separation mode is the same as that of liquid chromatography. It can be divided into normal phase (the polarity of the adsorbent is greater than the polarity of the eluent), and the reverse phase (the...)

Wednesday 18 September 2019

Hawach SPE Cartridges are made of medical grade PP and forming in one time. Frits are made of UHMW-PE. There is a variety of models to choose, such as Normal Phase Cartridge, Reversed Phase Cartridge, Ion Exchanges Cartridge, Mixed Mode Cartridges and so on. Here, We would like to...

Monday 16 September 2019

Reversed phase chromatography (RP) is the most widely used technique in high-performance liquid chromatography (HPLC) up to now, mainly because it is suitable for the analysis of most of them. Nonpolar substances and many ionizable and ionic compounds. Most stationary phases used...

Friday 13 September 2019

Some samples (such as avocado, peanuts, olive oil, etc.) contain more fat. Due to the limited solubility of fat in acetonitrile, the recovery rate of some fat-soluble pesticides (such as HCB, DDT, etc.) is reduced. How to overcome the low experimental results caused by fat? You can...

Thursday 12 September 2019

As an important branch of chromatography, high-performance liquid chromatography (HPLC) has become an important application of separation and analysis technology in the fields of chemistry, medicine, industry, agriculture, commodity inspection, and law inspection. Features of high-performance...

Wednesday 11 September 2019

When storing the column, the column should be filled with acetonitrile or methanol, and the column joint should be tightened to prevent the solvent from evaporating and drying. It is absolutely forbidden to leave the buffer solution in the HPLC columns for an overnight or longer period of time...

Tuesday 10 September 2019

According to the separation mechanism of substances, Chromatography can be divided into adsorption chromatography, distribution chromatography, ion exchange chromatography and the like. The operation mode of the adsorption thin layer chromatography refers to that the adsorption capacity...

Friday 16 August 2019

NH2 HPLC columns refer to the chromatographic columns that use silica gel as matrix carrier to bond amino groups. They are usually used for the analysis of carbohydrate compounds, and the mobile phase is usually methanol, acetonitrile and buffers salt solution. - The cleaning method...

Thursday 15 August 2019

The similarities FLASH and SPE are all column chromatography separation technology. FLASH is a fast separation mode for preparative chromatography, using optimized pre-packed low and medium pressure columns for chromatographic separation. The separation mechanism, stationary phase...

Wednesday 14 August 2019

The important technical parameters of Hawach SPE Columns are the key points of selection. Material The material selection of the SPE column is very important. The column material is in direct contact with the test object or analyte. The quality of material selection determines the...

Monday 12 August 2019

The system of an HPLC column is composed of a liquid, a reservoir, a pump, a sampler, a column, a detector and a recorder. - The packing material of HPLC columns - The packing material has high carbon content, small surface polarity, very low chemical purity and high surface separation...

Monday 12 August 2019

Solid phase extraction principle Solid phase extraction is a separation technique that combines selective retention, selective elution, and the like. When a complex sample solution passes through the sorbent, the sorbent selectively retains the aimed compound and a small number of...

Friday 09 August 2019

Reversed-phase chromatography (RPC) contains any chromatographic method using a non-polar stationary phase. The word “reverse” has a historical background. In the 1970s, most liquid chromatography was performed on unmodified silica or alumina. Their surface chemistry is hydrophilic...

Thursday 08 August 2019

Chromatography is a separation and analysis method and the separation is the core. Therefore, HPLC columns are the heart of the chromatographic system. The requirements for the column are high efficiency, good selectivity and fast analysis speed. Generally, the column length of about...

Thursday 08 August 2019

Most common SPE cartridges are injection syringes made of polyethylene, in which there are two plugs made of polypropylene or fiberglass, with a certain amount of chromatographic adsorbent (filler) between the two plugs. SPE cartridges without sieve plate 1. Avoid “non-specific adsorption” 2...

Saturday 03 August 2019

SPE cartridge can be divided into three classes on the markets: silica-based cartridges, polymer-based cartridges, and adsorption-based cartridges. And here we talk about the three types of silica-based cartridges. The first type is the C18 cartridges. This kind of cartridges bond...

Thursday 01 August 2019

It is important for the experimenters to use and maintain chromatographic columns correctly. They should focus on many some things so as to protect the columns in the using process. Here we talk about several attentions. Avoid changing pressure and temperature dramatically and any...

Wednesday 31 July 2019

Solid phase extraction (SPE), developed in the 1970s, can replace the traditional liquid-liquid extraction in many fields and has been applied more and more widely in the laboratory. The common solvent of SPE Hexane, isooctane, tetrahalide carbon, trihalomethane, dihalomethane, tetrahydrofuran...

Friday 19 July 2019

Bonded-phase chromatography is a liquid-liquid chromatography method in which a stationary phase is covalently bound to a carrier particle, which overcomes the mechanical shock in the distribution chromatography, the constant loss of the stationary phase and the gradual change of...

Thursday 11 July 2019

SPE column or SPE cartridges are based on liquid-solid phase chromatography theory, it is a kind of extraction, separation, concentrated sample preparation unit. Mainly used in sample pretreatment of various foods, agricultural and livestock products, environmental samples and target...

Tuesday 09 July 2019

The reversed-phase HPLC columns may be repeatedly injected into a sample containing a strongly retained material, and in particular, the sorbent components such as large molecular weight or hydrophobic biological flow proteins and strong alkaline substances may be adsorbed on the silica medium...

Tuesday 09 July 2019

Polymeric MCX SPE cartridges are used to extract strongly alkaline compounds. MCX is a mixed strong cation exchange adsorbent obtained by bonding sulfonic acid groups on highly crosslinked PS/DVB surface. It has both reverse phase and cationic exchange retentive properties and good...

Monday 08 July 2019

People should face are a lot of problems when using SPE cartridges. As a consequence, we will talk about why the cartridge has a low recovery rate in the experiments. The first reason for the low recovery rate is that the target object does not remain sufficiently on the fillers....

Friday 05 July 2019

When the polarity of the stationary phase is greater than the polarity of the mobile phase, it can be called normal phase partition chromatography or simply normal phase chromatography. If the polarity of the stationary phase is less than the polarity of the mobile phase, it can be...

Thursday 04 July 2019

C8 HPLC columns are used to isolate many organic compounds, which are one of the reversed phase silica gel columns. The maintenance of C8 HPLC columns requires organic solvents. Chromatographic grade methanol is recommended and different brands of chromatographic columns should be...

Thursday 04 July 2019

The filler of polymeric HLB SPE cartridges produced by a special copolymerization technology contains a certain proportion of the hydrophilic group and the hydrophobic group. Hydrophobic divinyl benzene structures retain nonpolar compounds and hydrophilic n-vinyl pyrrolidone structures...

Thursday 04 July 2019

(1) When loading and unloading or replacing the HPLC columns, the action should be light and the joint should be tightened properly. Strong mechanical vibration must be prevented to avoid voids in the bed. (2) If the instrument is used for routine analysis, the sample type is limited...

Tuesday 02 July 2019

The key to regenerating contaminated HPLC columns is to know the nature of the contaminants and to find the right solvent to remove. If contamination is caused by the accumulation of strongly retained materials during repeated injections, simple steps to remove these contaminants...

Monday 01 July 2019

After selecting the type of SPE cartridges, we have to determine the specifications of the SPE cartridge. The principle of selecting the SPE cartridge specification is to first ensure that the SPE cartridge packing has sufficient capacity to retain the target compound 100% on the column...

Friday 28 June 2019

Stationary Phase & Mobile Phase The stationary phase is used to separate the substances, which is packed into HPLC Column directly; Mobile phase is the carrier, which carries the substances into the stationary phase and goes through the stationary phase. It is gas in the vapor phase...