High performance liquid loop injectors

Fernandez Otero, G.C. Lucangioli, S.E. Carducci, C.N. Adsorption of drugs in high-performance liquid chromatography injector loops. J.Chromatogr.A, 1993, 654, 87-91... 

The end products of acid and enzymatic hydrolysis of corncob and sugarcane bagasse were analyzed by using a high-performance liquid chromatograph (Waters, Milford, MA) equipped with a Rheodyne automatic injector with a 20- iL injection capacity loop, a Shodex Sugar SC 1011 column, and an integrator model 747 with a model 410 RI detector. The mobile phase was deionized water, and the flow rate was adjusted to 0.8 mL/min. 

High Performance Liquid Chromatography. Tissue extracts were analyzed with a Varian model 5020 liquid chromatograph equipped with a Rheo-dyne model 7120 loop injector valve, a Tracer 970 variable wavelength detector set at 257 nm, an automated Hewlett-Packard 3385A printer-plotter system for determining retention times and peak areas, and a Waters /x Bondapak column (3.9 mm i.d. X 300 mm) for carbohydrate analysis. The buffer was eluted isocratically at 1 mL/min with a 1 4 (v/v) mixture of 0.01 M monobasic sodium phosphate (pH 4.46) and methanol. The minimum amount detectable was 10 ng. 

The LC system consisted of a Jasco 880 PU pump (JASCO, Tokyo, Japan) for the mobile phase, a Rheodyne Model 7125 injector with a 25 pL loop, and a 0.2 x 15 cm Mightysil RP-18 GP (5 pm) column (Kanto Chemical, Tokyo, Japan). LC was performed using an aqueous solution containing 80% MeCN as the mobile phase at a flow rate of 0.2 ml/min at 26°C. The column was connected to L-7455 diode array detector (Hitachi, Tokyo, Japan) with a flow cell (17.7 pL, 10 mm), and Hitachi D-7000 advanced high performance liquid chromatography (HPLC) system manager was utilized for data acquisition. 

The method of characterization by high-performance liquid chromatography [HPLC] is as follows 25 mg of hemicellulose was put into 50 mL volumetric flask and pure water was added to the mark. The mixture was shaken and then filtered [first few milliliters of filtrate was discarded]. The solution was then filtered through a membrane filter of 0.2 pm cellulose nitrate. Then about 100 mL solution was injected into the HPLC system via a loop injector with a 20 mL, using an isocratic elution system with distilled water with a mobile phase, flow rate 0.8 mL/min. The detection was made using a UV detector at a wavelength of 280 nm [34]. 

Loop Injectors for High Performance Liquid Chromatography (HPLC)... 

A high-performance liquid chromatograph from any suppliers. Must be capable of gradient-elution, flow-rates from 0.1 to 10 ml per min, at pressures up to 3000 p.s.i. Requires detection at 254 and 280 nm. Dual pen recorder. Injector loops of 50, 100 and 500 /tl vol. 

---