scholarly journals Screening method for the determination of selected tetracyclines in water by liquid chromatography with diode array detector

2014 ◽  
Vol 58 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Ewelina Patyra ◽  
Ewelina Kowalczyk ◽  
Krzysztof Kwiatek
Keyword(s):  
Oxalic Acid ◽  
Water Samples ◽  
Solid Phase ◽  
Screening Method ◽  
Gradient Elution ◽  
Environmental Water ◽  
Array Detector ◽  
Chromatographic Procedure ◽  
Oasis Hlb

Abstract A chromatographic procedure for determination of oxytetracycline (OXT), tetracycline (TC), chlorotetracycline (CTC), and doxycycline (DC) in water samples was developed and was applied for the analysis of water samples collected from poultry and pig farms and environmental water samples. Samples were acidified with trifluoroacetetic acid to pH 3 and further purified by solid phase extraction using Oasis HLB cartridges. The samples were dried up and redissolved in the mixture of oxalic acid and methanol. Separation was performed on reserved phase column (Phenomenex column C18 , 250 mm × 4.6 mm, 5 μm) by multistep gradient elution, and detection was carried out at 360 nm for OTC and TC, 370 nm for CTC, and 350 nm for DC. The tetracyclines were eluted with the mobile phase of 0.05 M oxalic acid (pH 2.5), acetonitrile, and methanol. This method provided average recoveries of 83.53% to 108.59%, with coefficient of variations (CVs) of 2.41% to 8.64% in the range of 10 to 1000 μg/L OTC, TC, CTC, and DC in water. The linearity for the tetracyclines was determined by HPLC-DAD in the range 10 to 1000 μg/L, with the correlation coefficient (R) > 0.99. The LOD and LOQ for the tetracyclines in water samples ranged from 1.51 to 4.00 and 2.51 to 5.93 μg/L, respectively.

scholarly journals Comparison of the Usefulness of SPE Cartridges for the Determination ofβ-Blockers andβ-Agonists (Basic Drugs) in Environmental Aqueous Samples

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Magda Caban ◽  
Piotr Stepnowski ◽  
Marek Kwiatkowski ◽  
Joanna Maszkowska ◽  
Marta Wagil ◽  
...  
Keyword(s):  
Water Samples ◽  
Solid Phase ◽  
Environmental Water ◽  
Direct Application ◽  
Environmental Water Samples ◽  
Basic Drugs ◽  
Aqueous Samples ◽  
Oasis Hlb ◽  
First Time

Even though the methodology used for the determination ofβ-blockers andβ-agonists in environmental samples is based mainly on solid-phase extraction (SPE) and gas chromatography or liquid chromatography with mass spectrometric detection, the available literature data on the applied SPE procedures is rather sparse. In this paper such comparison is presented. Moreover, the usefulness of the eight SPE cartridges for the determination of fiveβ-blockers (acebutolol, atenolol, metoprolol, nadolol, and propranolol) and twoβ-agonists (salbutamol and terbutaline) in environmental aqueous samples using GC techniques is tested. Among them, three (the trifunction sorbent Strata Screen C, the copolymers LiChrolut EN, and the functionalized copolymer Isolute ENV+) were used for the first time for this purpose. It was confirmed that polystyrene-divinylbenzene-N-vinylpyrrolidone copolymers (PS-DVB-VP, Strata-X, and Oasis HLB cartridges) have a better potential than a cation-exchange sorbent for the extraction of the target drugs from environmental water samples. However, it should be stressed out that the direct application of the tested SPE conditions for the analysis of real environmental water samples is not possible, and such parameters, like volume of loading sample, appropriate solvents for washing and elution steps, and so forth, must be optimized again in order to achieve satisfactory recovery values for the target compounds.

Liquid Chromatographic Screening Method for Fluorescent Derivatives of Chlorophenoxy Acid Herbicides in Water

1992 ◽  
Vol 75 (4) ◽  
pp. 720-724 ◽  
Author(s):  
Toshinari Suzuki ◽  
Satoru Watanabe
Keyword(s):  
Solid Phase Extraction ◽  
Water Samples ◽  
Solid Phase ◽  
Screening Method ◽  
Ethyl Esters ◽  
Separate Determination ◽  
Phase Extraction ◽  
Liquid Chromatographic ◽  
Acid Herbicides

Abstract A liquid chromatographic method for screening 9 chlorophenoxy acids (2,4-D; 2,4-DP; 2,4-DB; MCPA; MCPP; MCPB; 2,4,5-T; 2,4,5-TP; and 2,4,5-TB) and their ethyl esters in ground- and tap water is presented. The water samples are acidified and subjected to either liquid-liquid or solid-phase extraction. The extracts obtained are saponified in 0.03N NaOH-50% methanol (1+1) and the acidic compounds are re-extracted with ethyl acetate-n-hexane (8 + 2) after acidification and derivatized with 9- anthryldiazomethane. Derivatized compounds are analyzed using reversed-phase column chromatography with fluorescence detection (excitation, 365 nm; emission, 412 nm). Recoveries of analytes from 20 mL water samples were greater than 90%, and the average coefficient of variation was within 5.0% at 0.5 ppb for both extraction methods. These methods are simple and useful for the determination of small amounts of chlorophenoxy herbicides. Solid-phase extraction is suitable for screening a large number of samples simultaneously, and liquid extraction for separate determination of the acids and ethyl esters of the herbicides was improved by introducing a saponification step.

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