Problem When Use HPLC

(1) Mobile phase: must be used after chromatography through the filter after use, and the mobile phase ratio can not be completely in accordance with the standard.

 

(2) Abnormal column pressure: the bubble inside the column, with the syringe to the bubble out, the column pressure back to normal. Column height: internal obstruction problems occur.

 

(3) Accuracy of external standard method: the accuracy of the external standard method related to the determination of the results, so the injection must be accurate results, the standard peak area RSD value should be less than 2.0. The general injector should not have bubbles present when extracting samples.

 

(4) When the test sample or standard peak pinning phenomenon, should check whether the phenomenon of collapse of the column occurred, if any, then re-column or change the new pillars.

HPLC chromatography Column Application ——-in the Detection of Drug

Life Science,health care and pharmaceutical were get more and more focuses by human beings as fast develop of scientific technique. In the drug analysis, high performance liquid chromatography is widely used in the quantitative analysis of drug analysis because of its specificity,.With feature of high sensitivity, fast and simple characteristics, especially in the interference factors show more superiority.

Determination of Lomefloxacin in Lomefloxacin Hydrochloride Eye Drops by HPLC Column; Column C, 0.02tool / nm Acid Solution (pH adjusted to 2.6 with triethylamine) – acetonitrile (R = 0.9998), the average recovery was 100.4, and the RSD0 of the repeated injection was in the range of 0.48 ~ 0.72 g, and the peak was 287 nm. .33 (n-6).

Zhang Min and other high-performance liquid chromatography with high-performance liquid chromatography determination of baicalin in addition to the domestic also on the quinolones antibiotics n, compound amoxicillin powder amoxicillin and clavulanic acid mouth, compound cold liquid, Qinlian Oral solution of baicalin, hydrobromide dextromethorphan tablets, feed chloropyridine, injection of neviomycin sulfate, small oxytetracycline C2b, health food in the sildenafil and celestium, plant more The injury of camptothecin and its derivatives, feed thirteen kinds of sulfonamides and other drugs were studied. In the use of high performance liquid chromatography for determination with other technologies, the detector is generally UV spectrophotometer, mass spectrometry and so on. These sophisticated detectors determine the sensitivity of the analysis, which is important for the analysis and is an important component of high performance liquid chromatography (HPLC).

Starlab HPLC column with ideal anti-pressure tube made from SS316 Stainless Steel can be wide chemical compatible for global users application.C18 Universal and C8 Universal especially equivalent to Waters brand,100 000 grade clean room made sorbents with perfect efficiency and 100% no contamination.

With development of pharmaceutical and R&D of chromatography,Starlab will keep on bring more columns to make more users satisfaction and do contribute to life science and pharmaceutical industries.

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Brief Introductionof Normal Phase Chromatography

In the early eighties, the complex chromatographic stationary phase silica gel and pyridine thiocyanate nickel salt complex with the aromatic compounds to form inclusions for the separation of aromatic nitrogen isomers and cholesteric crystals. It has been the coke adsorbent as filler and bonded silica were compared and studied its thermodynamic mechanism. Large-pore polymers with ionized or non-ionizing functional groups also begin to be applied to liquid chromatography, which are stable over the entire acid-base range.

 

One of the disadvantages is that they will shrink and shrink when the solvent changes, but The main analytical aspects of the use, that is, the collection of traces of compounds from the water is no problem, through the appropriate treatment into the column, some substances appear excessive peak band widening, while others appear sharp, narrow peak And high resolution, in the strong alkaline porous resin 120 minutes can be separated from 100 kinds of urine in the UV absorption of substances. Some of the chain length of the carbon-hydrogen ligand bonded to the silica gel, according to the chain length and short effect of the retention value of the study, there have been similar reports, the C22 bond phase and the preparation of bonding phase load conditions In comparison, the bond length and the adsorption free energy can be linearly related. In general, the alkaline solution will destroy the silica gel, alkylamine than quaternary ammonium salt will corrode silicone filler, so by filling with 5mm silica gel short column to elute alkaline solution. Kataev et al with polytrifluorostyrene coated silica gel particle matrix and applied to the separation of halogenated aromatic hydrocarbons, peptides and proteins.

 

In November 1993, Majors discussed the rapid development of HPLC polymer fillers in Japan. Hosoya prepared the macroporous polymerization of ethylene-p-tert-butylbenzoate microspheres and two other polymer microspheres with more properties as well as more C18HPLC stationary phases.

HPLC Column Installation and Using Tips

High Performance Liquid Chromatography Column Structure:

Empty column assembled from the column joints, tube and frits ,end fittings .

In the two end fittings, a stainless steel filter (or strainer) is placed on both ends of the column for sealing the column packing and is not lost by the mobile phase. Empty column of the components are 316L stainless steel made can withstand the general solvent.because of the chloride-containing solvent to its corrosive, it should be noted that the column and the connection tube can not be long-term retention of such high chemical solvents to avoid corrosion.

 

The column installation

1)open the column box to confirm the type of column, size, date and the solvent stored in the column.

2) Remove the end fittings of the column at both ends of the sealing plug back into the box for backup.

3)Connect the inlet end of the column through the connecting pipe to the inlet of the injection valve (if the conditions permit, it is recommended to use the column before the column); the outlet of the column is connected with the detector. The connecting pipe is a stainless steel pipe ,be sure to try to reduce the dead volume outside the column when taking over. Connect the tube through the hollow screw, press the ring as far as possible after the force in the end, and then tighten the hollow screw clockwise until the screw does not move so far, remember not to force too much. If the column is pressurized by the mobile phase, use a wrench to continue 1/4 turn clockwise until it without leaks.

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Use Tips of HPLC Columns:

Prior to use, the column is best tested for performance and the results are stored as a reference for future evaluation of column performance changes. Note that column performance may vary depending on the conditions used for the sample, mobile phase, column temperature, etc.

In addition, the column performance test is performed in accordance with the conditions in the column factory report (factory test The conditions are the best conditions), the only way, the measured results are comparable.

 

After production finished, all Starlab HPLC products will send to QC department to do quality inspection.This way ensure only qualified products can release to market. Besides, certificate of Analyse will be sent to clients with products together.

 

More product info with different sorbents,kindly visit our website for detail. http://www.starlabsci.com/

How Move the Air in the Mobile Phase?

In the operation of HPLC, there is no bubble for the collapse? There is no shock for the ultrasound for an hour, the mobile phase also appeared bubbles, and fainted? There is no time for the weather when no bubbles, cloudy, rainy days, the same bottle, there is a bubble, and lost confidence in their work?

In the operation of high performance liquid chromatography, the mobile phase bubble, the whole work can not be carried out.

Ultrasonic shock for an hour of mobile phase, why the weather was fine when no bubbles, cloudy, rainy days will appear; because of cloudy, rainy weather drop, causing dissolved in the mobile phase of the air over saturation (sunny When the high pressure is not saturated), when the high-pressure pump to extract the mobile phase, the air precipitation, resulting in bubbles.

Ultrasonic shocks for an hour of mobile phase, why is there air there? This is due to shock in the atmospheric pressure, drive the air effect is not OK.

If the mobile phase of the bottle to take the vacuum, while the ultrasonic shock, the effect will happen? The effect is very good, as long as 1min, the mobile phase of the air almost gone; after such expulsion of the air mobile phase, cloudy, rainy days will not use the bubble; and save time, do not move for half an hour, one hour ultrasonic shock and the effect is very good.

Instructions of HPLC Column

Starlab HPLC column is a versatile, highly inert C18, C8 column that separates acids, bases and neutral compounds at the same time, with sharp and symmetrical, well-defined, well-guaranteed inter-column and inter-batch reproducibility From method development to routine analysis of seamless transfer.

 

In today’s field of analytical chemistry, chromatographic analysis has taken place, especially in drug analysis. For example, “Chinese Pharmacopoeia” 2005 edition of the two drugs have been collected nearly 43.1% of the drug quality standards to varying degrees, the use of high performance liquid chromatography analysis. Especially the compound preparation, impurities or accessories interference factors and more varieties using high performance liquid chromatography. It should be noted that with the European and American countries accounted for the mainstream of different chemical drugs, China’s pharmaceutical industry has been composed of traditional Chinese medicine and modern Western medicine. Therefore, in China, the HPLC method as a powerful means of drug analysis, put forward higher requirements: on the one hand to meet the separation of complex ingredients of traditional Chinese medicine; the other hand, the separation of various acidic and alkaline compounds in western medicine.

 

2005 version of the “Chinese Pharmacopoeia” is also a substantial increase in the HPLC content of the varieties, up to 479 species, accounting for about 41.8%. In the face of regulatory needs and increasingly competitive drug market, Starlab from the interests of the majority of users, timely introduction of inexpensive high-performance liquid chromatography column to meet such a market demand. Starlab columns are suitable for separating all kinds of traditional Chinese medicine and western medicine. At the same time with good reproducibility and durability, Starlab column will be its high cost performance and good technical support by the majority of users.

 

Starlab HPLC Column Category

1.1 C18-Aqueous Columns

1.2 C18-Universal Columns

1.3 C18-Low PH Columns

1.4 C18-Alkaline Columns

1.5 C8-Universal Columns

1.6 C8-Low PH Columns

1.7 C8-Fluorine Columns

1.8 C1 Columns

1.9 C4 Columns

1.10 SiO 2 Columns

1.11 NH 2 Columns

1.12 CN Columns

1.13 Phenyl Columns

1.14 Phenyl-Ether Columns

1.15 Polar RP Columns

1.16 SCX Columns

1.17 SAX Columns

1.18 Diol Columns

1.19 C30 Columns

1.20 Amino Acid Columns

1.21 PAH Columns

1.22 PFP Columns

1.23 HILIC Amide Columns

 

Pore size: 120Å,300Å

Particle size:3um,5um and 10um

Surface area(m 2 /g):90,160,320

PH Range :1.5~10/2~8

End Capped:Yes/No

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How to Selection of HPLC Filler

Matrix:
The HPLC filler may be a ceramic-based inorganic matrix or an organic polymer matrix. Ceramic properties of the inorganic matrix is mainly silica gel and alumina. Ceramic properties of inorganic matrix rigid, in the solvent is not easy to expand. The HPLC grade organic polymer is based on crosslinked styrene-divinylbenzene or methacrylate. The organic polymer matrix is less rigid and more compressible. Solvents or solutes tend to penetrate into the organic matrix, resulting in the expansion of the filler particles, resulting in reduced mass transfer and ultimately low column efficiency.

Silica gel:
Silica gel is the most common substrate for HPLC packing. In addition to having a high strength common to the inorganic matrix, it also provides a surface that binds a wide range of ligands through mature silylation techniques to produce inverting, ion exchange, hydrophobic, hydrophilic or molecular exclusion Chromatography. Silicone matrix packing for a wide range of solvents, from polar to non-polar. Its weakness is unstable in the water-soluble alkaline mobile phase. Typically, the silica gel matrix is recommended for conventional analytical pH ranges of 2-8.

HPLC Column with Silica Matrix

1. Normal phase chromatography
The stationary phase for normal phase chromatography is usually silica gel (Silica) and other bonded functional groups with polar functional groups such as amine groups (NH2, APS) and cyanide groups (CN, CPS).
Since the silica hydroxyl (SiOH) or other polar groups on the surface of the silica gel have a strong polarity, the order of separation is based on the polarity of the components in the sample, i.e., the weakly weak components are first washed out Column.
The mobile phase polarity used in the normal phase chromatography is relatively low compared to the stationary phase, such as: Hexane, Chloroform, Methylene Chloride and the like.
2. Reverse phase chromatography
The filler for reverse phase chromatography is usually a silica gel matrix, the surface bonding with a relatively weak polarity of the functional groups of the bond phase. The mobile phase used in reverse phase chromatography is highly polar, usually water, a mixture of buffer and methanol, acetonitrile and the like.
The order in which the samples flow out of the column is that the strongly polarized components are first washed out and the weakly polarized components are more retained on the column.
Commonly used reverse fillers are: C18 (ODS), C8 (MOS), C4 (Butyl), C6H5 (Phenyl) and so on.

Unsupported Hydrophilic PTFE Membrane Filter

Starlab Scientific special produced Hydrophilic PTFE Membnrane Filter ,including unsupported hydrophilic single membrane and PP supported composite material composite hydrophilic membrane filter.

 

Because it is a PTFE membrane with strong hydrophilic&chemical compatibility,Can be wetted with an aqueous solution with extremely excellent chemical compatibility and can withstand almost all organic solvents.It can be widely used to filter a variety of aqueous solutions, strong acid , Strong alkali ,organic solvent, mixed solvent, acid or alkali, strong oxidizing solution etc.Also called aqueous based solvent used PTFE.

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Features

v Strong hydrophilic characteristic and hydrophilic stability

v Excellent chemical compatibility

v Good mechanical performance

v Good anti-pollution characteristics

v Strong acid and alkali resistance

v Dry saving

v A variety of aperture, to meet different needs

v Very low chemical extractable level

v Hydrophilic,Use without pre-wetting

 

Applications 

1. High-purity electronic grade chemicals

2. Wet engraving and cleaning chemicals

3. Acid and alkali and solvent

4. High viscosity liquid

5. Ultra-pure water and deionized water

6. Microelectronics process of various cleaning

 

Hydrophilic PTFE Disc Size in supply:

Diameter:13,20,25,37,47,60,90,142,150,200,250,293,300mm

Pore size:0.1,0.22,0.45,0.65um

Hydrophilic PTFE Roll Size in supply:

260mm width,0.22,0.45,1.0um pore size.

Sterile MCE Gridded Membrane Filter 

Starlab Mixed Cellulose Esters (MCE) Gridded membrane filter made from mixture of CA(Cellulose acetate) and (CN) Nitrocellulose.Somes users use MCE to be institue of CN (Nitrocellulose)

It’s a general purpose filter used in many applications for the microbiological examination of water, wastewater treatment, pharmaceuticals, food, beverages analysis and air monitoring. MCE membranes offer high recovery rates and superior flow rates.

 

Features:

-Hydrophilic MCE membrane filter,excellent compatibility with aqueous , organic solvent or their mixtures.,low back ground response,extremely lower hplc extractable.

-Individually Wrapped or Multipack, and with or without Absorbent Pad

-Available Pore Sizes include 0.20um, 0.45um, 0.80um  for different microbe analysis.

-Dia of 47mm and 50mm available

-Colors include White and black Membranes

-Surfaces is gridded with white or balck blanket

-Contrasting grid lines facilitate counting colonies and are tested to assure freedom from grid line inhibition.

-Specifications & batch number printed on cover of each filter.

-Easy open pack and individually packing compatible with various membrane dispensers.

-Quality control tests are performed on each lot and Certificates of analysis will send together with each goods per oder.

Picture for innner pack of MCE gridded membrane   Scanning Electron Miscroscope Picture

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Applications

HPLC sample preparation

Colony Counting and Biological Monitoring

Bacterial biology research and Microbiological Analysis

Yeast and Mould Count