Separation of Tl(I)-Pb(II) by liquid-liquid extraction with diethyldithiocarbamic acid isolation of201Tl

The production of²⁰¹ Tl is described. Natural thallium is irradiated with protons and the induced²⁰¹Pb is separated from the target by liquid-liquid extraction with diethyldithiocarbamic acid in chloroform.²⁰¹Tl is separated from the mother activity (²⁰¹Pb) by liquid-liquid extraction with the same reagent. The decontamination of the final product (carrier free²⁰¹TlCl) is ≥5·10⁶ from the thallium of the target and>5×10⁴ from lead isotopes.     

Preparation and evaluation of [<Superscript>201</Superscript>Tl](III)-DTPA complex for cell labeling

Due to interesting physical properties and wide availability of ²⁰¹Tl as a SPECT radionuclide, the incorporation of this nuclide into DTPA for cell labeling was targeted. Thallium-201 (T _1/2 = 3.04 d) in Tl⁺ form was converted to Tl³⁺ cation in the presence of O₃/6M HCl and di-isopropyl ether, controlled by RTLC/gel electrophoresis methods. The final evaporated activity reacted with cDTPA in normal saline to yield [²⁰¹Tl](III)DTPA at room temperature after 0.5 hour, followed by solid phase extraction purification using C₁₈ Sep-Pak column (radiochemical yield >95%). Radiochemical purity of more than 99% was obtained using RTLC with specific activity of about 260 GBq/mmol. The stability of the tracer was checked in the final product in the presence of human serum at 37 °C up to 3 days. The partition coefficient was also measured. The labeled compound was used in red blood cell (RBC) labeling. The cell uptake ratio was determined at 4, 25 and 37 °C up to 3 hours.     

Octapeptide-Specific and Sensitive Assay for Angiotensin II in Plasma

Abstract

Angiotensin-(1–8)octapeptide (angiotensin II) is the active principle of the reninangiotensin system. Crossreaction of angiotensin II-antisera with inactive precursors and metabolic fragments prevented the specific quantitation of this hormone in biological fluids. Peptide-extraction on bonded-phase silica followed by peptide-separation using isocratic reverse-phase high performance liquid chromatography and subsequent radioimmunoassay rendered possible the octapeptide-specific measurement of angiotensin II in 2 ml plasma with a detection limit of 0.4fmol/ml. The coefficient of variation for intra-assay precision was 0.06 and for inter-assay precision 0.13. ¹²⁵Iangiotensin II was recovered from plasma by solid-phase extraction to 99±2% (mean ± S.D.). The overall recovery of 5, 10 and 20 fmol unlabeled angiotensin II added to plasma was 80±10%. Plasma concentrations in supine normal humans averaged 4.1 ± 1.6 fmol/ml and were suppressed below the detection limit by angiotensin I converting enzyme inhibition.     

Fission neutron spectrum averaged cross sections for threshold reactions on arsenic

Summary We have measured the cross sections, averaged over a ²³⁵U fission neutron spectrum, for the two high threshold reactions: ⁷⁵As(n,p)^75mGe and ⁷⁵As(n,2n)⁷⁴As. The measured averaged cross sections are 0.292±0.022 mb, referred to the 3.95±0.20 mb standard for the ²⁷Al(n,p)²⁷Mg averaged cross section, and 0.371±0.032 mb referred to the 111±3 mb standard for the ⁵⁸Ni(n,p)^58m+gCo averaged cross section, respectively. The measured averaged cross sections were also evaluated semi-empirically by numerically integrating experimental differential cross section data extracted for both reactions from the current literature. The calculations were performed for four different representations of the thermal-neutron-induced ²³⁵U fission neutron spectrum. The calculated cross sections, though depending on analytical representation of the flux, agree with the measured values within the estimated uncertainties.     

Online recovery of radiocesium from soil,cellulose and plant samples by supercritical fluid extraction employing crown ethers and calix-crown derivatives as extractants

Two crown ethers (CEs) viz. dibenzo18crown6, and dibenzo12crown7 and three calix-crown derivatives viz. (octyloxy)calix[4]arene-mono-crown-6 (CMC), calix[4]arene-bis(o-benzocrown-6) (CBC), and calix[4]arene-bis(naphthocrown-6) (CNC) were evaluated for the recovery of ¹³⁷Cs from synthetic soil, cellulose (tissue paper), and plant samples by supercritical fluid extraction (SFE) route. CEs showed poor extraction of ¹³⁷Cs from soil matrix. SFE experiments using 1 × 10^?3 M solutions of CMC, CBC and CNC in acetonitrile at 3 M HNO₃ as modifiers displayed better extraction of ¹³⁷Cs, viz. 21(±2) % (CMC), 16.5(±3) % (CBC), and 4(±1) % (CNC). It was not possible to recover ¹³⁷Cs quantitatively from soil matrix. The inefficient extraction of ¹³⁷Cs from soil matrix was attributed to its incorporation into the interstitial sites. Experiments on tissue papers using CMC showed near quantitative ¹³⁷Cs recovery. On the other hand, recovery from plant samples varied between 50(±5) % (for stems) and 75(±5) % (for leaves).     

Application of magnetic nanoparticles for the extraction of radium-226 from water samples

Bare (unmodified) and crown ether (CE)-modified Fe₃O₄ magnetic nanoparticles (MNPs) were investigated for the rapid extraction of ²²⁶Ra from water samples. It involved synthesizing the MNPs, introducing them into the sample solutions, ultrasonicating and agitating the suspension, magnetically separating the nanoparticles from solution, and measuring the ²²⁶Ra content in the supernatant. Experimental parameters such as salt choice, salt concentration and pH were optimized to achieve maximum extraction of ²²⁶Ra onto the MNPs. ²²⁶Ra content was determined using a Hidex 300SL liquid scintillation counter with α/β separation capability, or a gamma spectrometric detection system. The bare Fe₃O₄ nanoparticles showed significant pH dependence for the extraction of ²²⁶Ra from an aqueous solution over a pH range of 2–10. They gave an extraction of 95 ± 1 and 98 ± 1 % at pH 9 in 0.1 M NaCl and 0.1 M NaClO₄, respectively, whereas an extraction of 8–24 % was obtained, over the pH ranges from 2 to 5. The CE-modified MNPs yielded extraction efficiencies as high as 99 ± 1 % in the presence of 0.01 M picric acid at pH 4. This study demonstrates that the surface functionalization of Fe₃O₄ MNPs with suitable ligand modification can offer a selective mode of extraction for ²²⁶Ra in the presence of its daughter progenies.     

A comprehensive chromatographic comparison of amphetamine and methylamphetamine extracted from river water using molecular imprinted polymers and without the need for sample derivatization

This work explores the differences between two GCMS instruments for the determination of amphetamine and methylamphetamine extracted from water samples (ultra pure water and river water) without the necessity for derivatization. The instruments contained different generations of gas chromatograph and mass selective detector components and revealed significantly different results when presented with the same samples. The extraction methodology also compared two SPE systems. The extraction efficiency of commercially available molecular imprinted polymers as a sorbent in SPE was compared with commonly used hydrophilic balance sorbent. Molecular imprinted polymers provided excellent recoveries (81 ± 2% and 108 ± 3% at 30 μg L^?1, and 94 ± 2% and 94 ± 2% at 200 μg L^?1 for amphetamine and methylamphetamine, respectively). The best LOD obtained was sufficient for the determination of both drugs extracted from river water (0.029 ± 0.003 and 0.015 ± 0.004 μg L^?1 for amphetamine and methylamphetamine, respectively). These were comparable to literature values obtained through conventional extraction and analysis using LC‐MS/MS but had the advantage of being achieved using an underivatized GCMS method.     

Pressurised fluid extraction of polycyclic aromatic hydrocarbons and their polar oxidation products from atmospheric particles

An effective method utilising pressurised fluid extraction (PFE) to simultaneously extract polycyclic aromatic hydrocarbons (PAHs) and their polar oxidation products from atmospheric particulate matter (PM) is presented. The PFE method is advantageous over the traditional Soxhlet extraction due to its lower solvent consumption (9 mL compared to 90 mL) and shorter extraction time (15 min versus 18 h). Seventy compounds including PAHs and polar PAH oxidation products containing carbonyl (oxy-PAHs), hydroxyl (hydroxy-PAHs), and carboxylic acid (carboxy-PAHs) groups were targeted in the extraction of two different PM matrices: wood smoke (WS) and diesel exhaust (DE) PM. The PFE method was optimised and then compared to Soxhlet extraction for both PM matrices. The overall amounts of PAHs and their derivatives extracted from WS PM were slightly higher for the optimised PFE method (1849 ± 21 and 1863 ± 25 µg g^?1 with dichloromethane (DCM) and methanol (MeOH), respectively) than those obtained with Soxhlet extraction (1726 ± 33 and 1769 ± 22 µg g^?1 with DCM and MeOH, respectively). For DE PM (standard reference material (SRM) 2975) the overall amounts extracted by both methods were similar (average of 165 ± 6 µg g^?1), agreeing with previously published values. The detailed evaluation of extraction efficiencies for WS PM showed similar amounts for unfunctionalised PAHs (1100 µg g^?1) for both methods and solvents. For DE PM the mass yields for PAHs using PFE with DCM (62 ± 1 µg g^?1) were the highest and nearly 20% higher than those obtained with MeOH (53 ± 2 µg g^?1). The total mass yields of carboxy and hydroxy-PAHs from WS PM were also similar (412 ± 18 and 407 ± 11 µg g^?1) for PFE and Soxhlet with MeOH, and higher than when DCM was used (371 ± 5 and 379 ± 12 µg g^?1 for PFE and Soxhlet, respectively). For both matrices, the PFE yields for oxy-PAHs were higher than those obtained with Soxhlet.     

Determination of Halide Traces in Environmental Samples by Mass Spectrometric Isotope Dilution Analysis

Abstract

Since 1985, the Goulden large-sample extractor (GLSE) has been used to isolate a broad array of trace-organic contaminants from large volumes of water. In this study, field-applied quality control measures, including matrix and surrogate spikes and blanks, were used to monitor method performance from GLSE extraction through GC-MS analysis. The method was applied to the determination of multiple classes of pesticides isolated from 4- to 112-L filtered surface-water samples. Average recoveries of six surrogate compounds ranged from 84 ± 18% for [²H₁₀]diazinon to 15 ± 13% for 4,4′-[²H₈]DDT, the low recoveries for which were largely a result of unmonitored breakdown of this surrogate by the GC injection system. Field-matrix-spike samples were prepared by fortifying 10-L, 35-L, and 110-L filtered surface-water samples with 68 pesticides to amended concentrations of 11-to 50-ng/L each. Recoveries ranged from not detected to greater than 100%. Variability in pesticide recoveries from triplicate 10-L water samples collected at one site averaged 5.7% relative standard deviation and did not exceed 19%.     

High yield synthesis and characterization of isotopically enriched monoethylmercury chloride (C2H5201HgCl)

An important but commercially unavailable compound isotopically enriched monoethylmercury chloride (C₂H₅²⁰¹HgCl), has been synthesized from commercially available ²⁰¹HgO (98.11% enriched isotopic purity) and tetraethyltin. The required synthesis time is 1 h at 90 °C, and the product is the single product of monoethylmercury chloride, yielding more than 95% as ²⁰¹Hg in C₂H₅²⁰¹Hg⁺ (98.19 ± 0.22% enriched isotopic purity). The synthesized product was analyzed with high‐performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC‐ICP‐MS) to determine its concentration, isotopic composition and purity. The synthetic isotopically enriched monoethylmercury synthesized can be used in speciated isotope dilution mass spectrometry (SIDMS) and isotope dilution mass spectrometry (IDMS) analyses as a standard. Copyright © 2005 John Wiley & Sons, Ltd.     

Antioxidant and binding properties of methanol extracts from indigo plant leaves

This study was conducted to clarify the effect of ultra-pressure treatment on the extraction of bioactive compounds from indigo plant leaves (Polygonum tinctorium Lour.) and on their properties. Leaves were harvested the in mid-August, 2013, from Naju City (Korea), and treated using two methods: ultra-pressure (550 MPa, 3 min) and hot-air (70°C, 24 h). Then, the leaves were ultrasonically extracted with methanol. The content of indirubin in leaves treated with ultra pressure and hot air was (535.55 ± 26.14) mg kg^?1 and (52.63 ± 6.45) mg kg^?1, respectively, and that of tryptanthrin was (165.55 ± 8.74) mg kg^?1 and (153.00 ± 7.62) mg kg^?1, respectively. Polyphenolic content in the leaves extract was (127.24 ± 13.67) mg kg^?1 after the ultrapressure and (88.22 ± 5.33) mg kg^?1 after the hot-air treatment. The content of flavonoids was (2298.67 ± 83.27) mg kg^?1 after the ultra-pressure and (3224.00 ± 21.45) mg kg^?1 after the hotair treatment. Di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) radical scavenging activities of the indigo extract obtained by ultra-pressure and hot-air treatment methods at the concentration of 1 mg mL^?1 were (80.25 ± 0.73) % and (66.54 ± 2.35) %, respectively, and 2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activities were estimated as (90.14 ± 0.79) % and (64.45 ± 8.97) %, respectively. The methanol leaf extract after ultra-pressure treatment exhibited higher binding properties to human serum albumin in comparison with catechin and conventional treatments. Consequently, it was assumed that the ultra-pressure treatment is an effective method for the extraction of bioactive compounds from indigo leaves.     

Determination of Atmospheric Polycyclic Aromatic Hydrocarbons Using Accelerated Solvent Extraction

Abstract

An accelerated solvent extraction (ASE) method has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) present in both atmospheric particulate and gaseous phases in this study. Extraction parameters such as the combination of solvents, extraction temperature, and static extraction time were investigated and optimized. Effective extraction was achieved using a 3:1 mixture of n-hexane and acetone as extraction solvents at 100°C in 30 min for all the compounds studied. The optimized extraction method was compared with conventional extraction methods and validated using National Institute of Standards and Technology (NIST)–certified standard reference material (SRM) 1649a. The recoveries obtained for certified 12 PAHs were in the range of 82–126% with relative standard deviation (RSD) between 6 and 28%. The validated ASE technique was used followed by gas chromatography–mass spectrometry (GC-MS) for the determination of PAHs distributed between gaseous and particulate phases in the atmosphere of Singapore. Total average concentrations of PAHs in air samples were 33.54 ± 19.32 ng m^?3, with 4.72 ± 2.80 ng m^?3 in particulate phase and 28.82 ± 16.92 ng m^?3 in gaseous phase, respectively. The results obtained from this study are compared to those reported from other areas of the world.     

Alpha spectroscopic analysis of actinides (Th,U and Pu) after separation from aqueous solutions by cation-exchange and liquid extraction

The radioactivity concentration of ²³⁶Pu, ²³²U and ²²⁸Th in aqueous samples has been determined by means of alpha spectroscopy after chemical separation and pre-concentration of the radionuclides by cation exchange and liquid–liquid extraction using the Chelex-100 resin and 30% TBP/dodecan, respectively. Method calibration using a ²³⁶Pu standard solution containing the daughter radionuclides results in a detector efficiency of 18% and in a chemical recovery for cation-exchange which is (30 ± 7)%, (90 ± 5)% and (20 ± 5)% for plutonium, uranium and thorium, respectively. The chemical recovery for liquid–liquid extraction is found to be (60 ± 7)%, (50 ± 5)% and (70 ± 5)%, for plutonium, uranium and thorium, respectively. The differences in the efficiencies can be ascribed to the oxidation states, the different actinides present in solution. Taking into account that the electrodeposition of the radionuclides under study is quantitative, the total method efficiency is calculated to be (18 ± 15)%, (46 ± 7)% and (15 ± 5)%, for plutonium, uranium and thorium, respectively, at the mBq concentration range. The detection limit of the alpha spectrometric system has been found to be 0.2 mBq/L, suggesting that the method could be successfully applied for the radiometric analysis of the studied radionuclides and particularly uranium in aqueous samples.     

“Surface-photografting”: new applications to synthetic fibers

“Surface-photografting” with UV-irradiation of polypropylene (PP) fiber and film and high-strength polyethylene (HSPE) yarn has been made with acrylic acid (AA) and acrylamide (AM) as monomers and benzophenone (BP), 4-chlorobenzophenone (4-BCP) and hydroxylcyclohexylacetophenone (HHA) as photoinitiators using a new continuous method. The grafting reaction occurs in a thin liquid layer on the fiber or film substrate, which is presoaked in a solution containing initiator and monomer. After irradiation with a highpressure mercury lamp, HPM 15 (2 kW) from Philips, for 5–20 sec at about 50°C the fiber and film surface is completely covered with a 2–8 nm thick layer of grafted polymer, analyzed by electron spectroscopy for chemical analysis. The grafting efficiency is 70–80%, i.e. only 20–30% of the polymer is homopolymer which can be removed by extraction. The grafted layers are so thin that they cannot be analyzed as weight increase (<0.1% of fiber weight). Absolute values for the amount of grafted AA polymer is analyzed by microtitration of the COOH groups at the fiber surface. The results agree well with the relative ESCA values. Grafting of commercial PP yarn with AA increases the adsorption of Crystal Violet dye with a factor of about 6. Grafting the same yarn with AM increases the adhesion to epoxy resin by a factor of 3–4 without affecting the mechanical properties of the fiber more than a few percent. For comparison, strips of blown PP film (5 mm wide) are modified by “surface-photografting” with AM. With increasing grafting, the contact angle for drops of distilled water decreases from 90° to 20°, indicating extensive wetting. The adhesion to epoxy resin increases from about 0.35 to 1.7 N/mm², i.e. with a factor of about 5 when the film surface is completely covered. Other comparisons are made with grafting of commercial HSPE yarn. Grafting with AA increases the adsorption of Crystal Violet dye by a factor of about 6. Grafting with AM increases the adhesion to epoxy resin from 0.25 to 1.3 N/nm², i.e. with a factor of 5. The bulk mechanical properties of the HSPE filaments are not affected by the grafting measured as tensile strength 2.7±0.1 GPa, elongation at break 4.8±0.3%, and Young's modulus 55±3 GPa, both before and after “surface-photografting”.     

Accurate Determination of Tributyltin in Tannery Wastewater by a New Procedure Using ID-HPLC–ICP-MS Combined with Low Temperature Extraction

Isotope dilution mass spectrometry is recognized as a primary method to obtain traceable values in the measurement of substances including trace elements and their organometallic compounds. This paper reports a novel method where isotope dilution high performance liquid chromatography inductively coupled plasma mass spectrometry (ID-HPLC–ICP-MS) was combined with low temperature extraction for the determination of tributyltin (TBT) in tannery wastewater from the leather industry. It has been found that the liquid–liquid extraction at very low temperature is in the favor of extraction of organotin, as the enrichment factor for low temperature (?80 °C) extraction was about 1.3 times higher than for extraction at room temperature (20 °C). The method detection limit of TBT, obtained from the proposed ID-HPLC–ICP-MS procedure after extraction with a sample volume of 7.5 by 2.5 mL of organic phase, was found to be 0.13 ng g^?1. When TBT was determined in a range of 10–1000 ng g^?1 in tannery wastewater samples, the analyte recoveries were in the range 90.1–107.2% with relative standard deviations of between 2.0 and 7.2%. Finally, the new method of ID-HPLC–ICP-MS combined with low temperature extraction was applied to the determination of TBT in actual tannery wastewater. The TBT contents from three different tanning procedures (chrome tanning, vegetable tanning and aldehyde tanning), expressed as the mean ± the expanded uncertainty (k = 2) were 378.65 ± 20.38, 110.04 ± 5.96 and 690.17 ± 35.31 ng g^?1, respectively.     

The use of SEP-PAKTM C18 Cartridges in the Preparation of Bile Acid Methyl Ester Acetates

Abstract

A method is described for the rapid and Quantitative extraction of bile acid derivates by Sep-Pak^TM C₁₈ cartridge. The method is used for the preparation of bile acid methyl ester acetates. The method was validated by determining the efficiency and the recovery of radiolabelled taurine-conjugated and free bile acids and of bile acid containing biological samples, by thin-layer chromatography with zonal scanning after each step and by internal standardization withing the gas-chromatographic analysis. The recovery of bile acids after hydrolysis amounted to 93.7% ± 2.7%, 97.7% ± 3.6% and 100% ± 2.3% for gallbladder bile, serum bile and mixtures of pure bile acids resp. The recovery of cholic acid methyl ester acetate and chenodeoxycholic acid methyl ester acetate after the entire procedure, including hydrolysis Sep-Pak^TM -extraction, methylation, acetylation and again Sep-Pak^TM -extraction, amounted to 85.6% ± 4.6%, 88.4% ± 5.3% and 89.3% ± 3.5% for gallbladder bile acids, serum bile acids and bile acid mixtures resp. It is concluded that Sep-Pak^TM can efficiently be used in the preparation of bile acid methyl ester acetates, thereby avoiding time-consuming and inconsistent extractions.     

Retention profile of Fe,Mn and Cu onto chemically treated polyurethane with carbon disulfide

Dithiocarbamate modified polyurethane foam (DTC-PUF) was synthesized as a new solid-phase extraction sorbent for the preconcentration and determination of Fe(II), Mn(II) and Cu(II) in environmental samples using flame atomic absorption spectrometry. Maximum extraction of the elements was achieved at pH 5–7 and flow rate 3 mL min^?1. Quantitative desorption was achieved by 10 mL from 1.0 mol L^?1 HCl solution. The capacity of the sorbent was 149.2 ± 0.5, 237.5 ± 0.2, 200.2 ± 0.1 μg g^?1 and the limit of detection was of 0.015, 0.015 and 0.012 μg mL^?1for Fe(II), Mn(II) and Cu(II), respectively. A preconcentration factor of 100 was obtained for all elements. The developed method was successfully applied to the determination of the tested elements in water (tap and lake) and plant (spinach and parsley leaves) samples and showed good recovery values from 98 to 111% with corresponding RSD values ranged from 0.6 to 8.6%.     

A study of the extraction of plutonium from planchets by Aridus–ICP–SFMS

Two extraction processes of plutonium (Pu) on planchets from alpha spectrometry (AS) have been evaluated by inductively coupled plasma sector field mass spectrometry with a desolvator system (Aridus–ICP–SFMS). The samples were traced with known concentrations of ²³⁹Pu (1.2 × 10³ fg) and ²⁴²Pu (2 × 10³ fg) followed by an electrodeposition in planchets, according to the Hallstadius method. The processes of extraction were carried out with 50 mL of 0.36 mol L^?1 HNO₃ every 30 min up to 180 min in a glass beaker at 60 °C. The first process was on a hotplate and the second used an ultrasonic system. Finally, samples were evaporated to dryness, and resuspended in 10 mL of 0.72 mol L^?1 HNO₃ for evaluation. The results showed that at 120 min, a ~70 % recovery of ²³⁹Pu and a ~80 % recovery of ²⁴²Pu in both processes were obtained. The average recoveries of ²³⁹Pu and ²⁴²Pu at 180 min using the hotplate in plate were 93.4 ± 4.6 and 93.7 ± 4.2 % respectively, and with the ultrasonic system were 96.0 ± 4.3 and 98.2 ± 1.0 % respectively. In conclusion, both processes are suitable for Pu extraction, and Aridus–ICP–SFMS is an essential technique for the reassessments and quantification of Pu. In addition, procedural blanks spiked with 1 × 10² fg mL^?1 U were prepared for each process, in order to study the contribution of the ²³⁸U on the background signal at m/z = 239, which was 0.5 ± 0.2 cps, indicating that the contribution of ²³⁸U on the ²³⁹Pu signal was negligible. Furthermore, this methodology can be applied to sample planchets with environmental, food, biological and nuclear origin, and thereby to avoid repetitive analysis when Pu concentration determined by AS are under minimum detectable activities.     

Radiochemical determination of plutonium in marine samples by extraction chromatography

Very low levels of plutonium (^239,240Pu and ²³⁸Pu) in marine samples (sea water,sediments, marine organisms) are determined by extraction on columns of tri-n-octyl phosphine oxide supported on microporous polyethylene (Micro thene-710), electrode- position, and α-spectrometry. ²³⁶Pu or ²⁴²Pu is added as the yield detector and a high-resolution α-spectrometer is used for counting. The final recoveries are 62.6% ± 9.7(σ)for sea water, 45.4% ± 9.6(0) for sediments and 81.7%± 4.5(σ) for marine organisms. Themethod enables ^239.240pu and ²³⁸Pu to be detected at the femtocurie level.     

Determination of Cefpodoxime Levels and Cefpodoxime Stability In Human Urine By Direct Injection HPLC with Column-Switching

Abstract

A semi-automated method providing on-line sample extraction and quantitative analysis for cefpodoxime in human urine, injected directly into the HPLC, is reported.

Samples were filtered by the analyst, injected into the HPLC system with an autosampler and loaded onto a 3 cm RP-18 precolumn with a mobile phase consisting of 10% methanol in 0.2% phosphoric acid and then automatically eluted onto a RP-18 analytical column using a mobile phase containing 7% acetonitrile in pH 5.2 sodium acetate buffer. the mean between-day precision of the standards was ± 4.29%. Spiked urine control recovery averaged 96 ± 6% for controls ranging from 1.0 to 20.0 μg/mL. the limit of quantitation for the method was 0.11 μg/mL.