Mobile phase detector

It should be noted here that in specifying the rules for the first probe (phenols), it became clear that rules for choosing the column and mobile phase interact significantly with detector rules. 0.1% acetic acid works well as a competing acid additive in terms of chromatography of the phenols. However, carboxylate ions are known to quench the fluorescence of phenols. Thus, if one were to use a fluorescence detector for trace phenol detection, an alternative competing acid, such as 0.1% phosphoric acid should be substituted. It was decided that mobile phase/detector interaction rules would be the first detector rules to be added to the knowledge base. 

FLOW RATE MOBILE PHASE DETECTOR TEMPERATURE ... 

Figure 1.1 HPLC chromatograms of samples of fluoxetine hydrochloride from four different suppliers (A-D). Reproduced from [7], Reproduced by permission from the publisher and authors. (Column 250 X 4.6 mm i.d. 5 pm Zorbax SB-C8 mobile-phase gradient acetonitrile water triflu-oroacetic 20 80 0.07 for 5 min, to 85 15 0.07 over 25 min, maintain at 85 15 0.07 for 5 min, return to initial conditions over 5 min, re-equilibrate for 10 min flow rate 1 mEmin injection 10 pi of 10 mg/ml solution in the initial mobile phase detector UV 260 nm.)...

Food/Topic Sample Pre-Treatment Column Mobile Phase Detector Reference... 

Temperature, reagent source, instrument, column age, column type, pH, mobile phase, detector type... 

Christie and Breckenridge (42) describe the application of this column to the isolation and determination of FAs containing trans double bonds in samples of natural and industrial origin. A column (250 X 4.6-mm ID) of NUCLEOSIL 5SA was flushed with 1% ammonium nitrate solution at a flow rate of 0.5 ml/min for 1 h, then with distilled water at 1 ml/min for 1 h. Silver nitrate (0.2 g) in water (1 ml) was injected onto column via the Rheodyne valve in 50-yu.l aliquots at 1-min intervals silver began to elute from the column after about 10 min, and 20 min after the last injection the column was washed with methanol for 1 h, then with 1,2-dichloroethane-dichloromethane (1 1 v/v) for 1 h. For most of the analytical work, the column temperature was maintained at 30°C in a thermostatted oven. 1,2-Dichloroethane-dichloromethane (1 1) (mixture A) at a flow rate of 1.5 ml/min was the mobile phase (detector operated at 242 nm) for the separation of isomeric monoenes, and the same solvents with the addition of 0.5% acetonitrile (mixture B) at a flow rate of 0.75 ml/min were employed for isomeric dienes and trienes. 

Type of sample Sample preparation Stationary phase Mobile phase Detector Ref. 

Compound Column, mobile phase Detector D.L.a Refs. 

Robustness Systematically change chromatographic conditions (examples column temperature, flow rate, gradient composition, pH of mobile phase, detector wavelength). Check influence of parameters on separation and/or peak areas. 

Air in mobile phase, detector cell, or pump. 1. Degas mobile phase. Flush system to remove air from detector cell or pump. 

Chromatography is a very versatile technique offering a wide range of solid phase materials and detector types which can deal with very complex mixtures. In practice all materials and conditions used in the instrument are carefully chosen to match the type of sample mixture involved. This includes selection of stationary phase (chemical and physical properties) column type and length sample pretreatment, operational temperatures, pressures, and flow rates physical and chemical nature of mobile phase detector type and so forth. Detection to nanogram level is quite common and some systems can detect to picogram level using very small volumes of sample. 

Detection Column Mobile Phase Detector Flow Rate... 

Compound Matrix Column Mobile Phase Detector LOD (ppt) Ref. 

Sample Matrix Preparation -Water and Cyanobateiial Matrices. Phase Mobile Phase Detector Methods Analytes (MC-LR) (MC-LR) Reference... 

Conductometric Detector Characteristics. Universal for aU anions or cations in solution (i.e., a bulk property of mobile phase detector) nondestructive concentration detector compound sensitivities differ over an order of magnitude range, useable... 

Publication year [Reference] Authors Application Column Mobile phase Detector Comments... 

Column Mobile phase Detector Substance Refs. 

Analyte(s) Co-analyte (Internal Standard) Column Mobile Phase Detector (nm) Page... 

---