Hydrolysis solid-phase extraction

Urine p-glucuronidase hydrolysis, solid-phase extraction HPLC/APCI-MS 0.6 ng/mL >90% Blount et al. 2000... 

The first bioanalytical application of LC-GC was presented by Grob et al. (119). These authors proposed this coupled system for the determination of diethylstilbe-strol in urine as a replacement for GC-MS. After hydrolysis, clean-up by solid-phase extraction and derivatization by pentafluorobenzyl bromide, the extract was separated with normal-phase LC by using cyclohexane/1 % tetrahydrofuran (THE) at a flow-rate of 260 p.l/min as the mobile phase. The result of LC-UV analysis of a urine sample and GC with electron-capture detection (ECD) of the LC fraction are shown in Ligures 11.8(a) and (b), respectively. The practical detection limits varied between about 0.1 and 0.3 ppb, depending on the urine being analysed. By use of... 

This method is used to simplify a chromatogram by reducing the number of compounds in a sample to the six aglycons. This protocol describes the dilution, preparation (including solid phase extraction and acid hydrolysis), filtration, and reversed-phase HPLC analysis of the sample. 

Total thiamine Baby food cereals cookies Acid hydrolysis with 0.1 M hydrochloric acid at 100°C for 30 min enzymatic hydrolysis of thiamine phosphates to thiamine with takadiastase at 47°C for 3 h weak ion-exchange (methyl-carboxylatein, add form) solid-phase extraction/ cleanup Analytical Lichrospher 100RP-18 (125 X 4 mm, 5 /u.m Merck ). Isocratic methanol + 10 mM phosphate buffer, pH 2.8 containing 5 mM sodium hexane-sulphonate + tri-ethylamine (15 + 84.9 + 0.1, v/v/v). 1.0 ml/min. UV absorbance 254 nm. External standardization. 79 Linear range = LoD to 7 /zg/ml thiamine, r = 0.9995. Reproducibility CV < 3% using food samples (n = 10). Recoveries 92.1-96.0% thiamine using baby food (n = 3). Samples spiked before hydrolysis. 

Pyrethroid type Cereals Nonpolar solvent extraction-solid-phase extraction Differential pulse polaro-graphy of 3-methoxybenz-aldehyde produced from pesticides by alkaline hydrolysis [140]... 

M. Noami, M. Kataoka and Y. Seto, Improved tert-butyldimethylsilylation gas chromatographic/ mass spectrometric detection of nerve gas hydrolysis products from soils by pretreatment of aqueous alkaline extraction and strong anion-exchange solid-phase extraction, Anal. Chem., 74, 4709-4715 (2002). 

M. Katagi, M. Tatsuno, M. Nishikawa and H. Tsuchihashi, On-line solid-phase extraction liquid chromatography-continuous flow frit fast atom bombardment mass spectrometric and tandem mass spectrometric determination of hydrolysis products of nerve agents alkyl methylphosphonic acids by p-bromophenacyl derivatization, J. Chromatogr., A, 833, 169-179 (1999). 

Urine (S-phenyl-mercapturic acid Solid-phase extraction hydrolysis derivatization HPLC 1 mq/l NR Einig and Dehnen 1995... 

Several new brevetoxin derivatives have been isolated and identified in K. brevis and natural blooms by solid-phase extraction and liquid chromatography (LC)-MS(MS) techniques <2006MI104>. These analogues are more polar than the previously reported brevetoxin derivatives and are poorly extractable by nonpolar solvents. They are novel derivatives and result from the hydrolysis of the A-ring and/or oxidation of the formyl group of some known derivatives. 

The variations concern pH, temperature, time of processing, and, in the last case additionally, possible ultrasonic treatment. The following step consists in a liquid-phase or solid-phase extraction (SPE). However, other extraction methods like SFE ° also have been used prior to the detection procedure. The final choice of the workup procedure is mainly dependent on the chemical stability of the analyte e.g., benzodiazepines are highly unstable under alkaline conditions, but they are also affected under acid conditions. Alkaline hydrolysis should be avoided for cocaine - however, morphine can be extracted after acid or alkaline hydrolysis. ... 

Like the hydrolysis methods, many extraction procedures have been described. Table 3 presents the various procedures and the compounds used as IS. With the development of the technology and the introduction of gas chromatography coupled with mass spectrometry (GC/MS), deuterated IS have been used for the quantification of cannabis in hair. Presently, this technique represents the state of the art. Most authors use liquid-liquid extraction only Moeller and Moeller et al. - have reported solid-phase extraction (SPE) procedures. 

Another MEKC separation (75 mM SDS, phosphate-borate buffer, pH 9.1) was reported for die determination of ll-nor-A-9-tetrahydrocannabinol-9-carboxylic acid, the major metabolite of A-9-tetrahydrocannabinol present in urine (Wemly and Thormann, 1992a). Sample treatment included basic hydrolysis of urine (5 mL), solid phase extraction, and concentration. The resulting sensitivity was 10 to 30 ng/mL (i.e., comparable to the cutoffs of immunoassays). Again, detection was by on-line recording of peak spectra, by means erf fast-scanning UV detector. 

Wernly et al. (1993) reported also an attempt to use MEKC, without hydrolysis, to determine morphine-3-glucuronide, the major metabolite of morphine (and heroin) in urine. The sensitivity limit (about 1 /ug/mL after solid-phase extraction and concentration) was unsatisfactory for confirmation of the results of the usual enzyme immunoassays, but improvements were deemed to be achievable. 

Sample handling strategies for the determination of plant phenols in food and plant material have been reviewed [42]. Attention was paid to hydrolysis, liquid extraction, solid-phase extraction (SPE), and supercritical-fluid extraction. 

An HPLC-DAD method was developed for the separation and the determination of flavonoid and phenolic antioxidants in commercial and freshly prepared cranberry juice.Two sample preparation procedures were used with and without hydrolysis of the glycoside forms of flavonoids carried out by the addition of HCl in the step prior to solid-phase extraction (SPE). The flavonoid and phenolic compounds were then fractionated into neutral and acidic groups via a solid-phase extraction method (Sep-Pak Cig), followed by a RP HPLC separation with gradient elution with water-methanol-acetic acid and a detection at 280 and 360 nm. A comparison of the chromatograms obtained for extracts prepared with and without hydrolysis showed that flavonoids and phenolic acids exist predominantly in combined forms such as glycosides and esters. In a freshly squeezed cranberry juice, for instance, 400 mg of total flavonoids and phenolics per liter of sample was found, 56% of which were flavonoids. Quercetin was the main flavonoid in the hydrolyzed products, where it accounted for about 75% of the total flavonoids, while it was absent in the unhydrolyzed products. 

King, J. W. and King, L. J. 1996. Solid-phase extraction and on-disc derivatization of the major benzodiazepines in urine using enzyme hydrolysis andToxi-Lab Vc-Mp3 column, 7. Anal. Toxicol., 20 262-265. 

DNA isolation from any tissue of interest after compound administration followed by (1) addition of stable isotope-labeled internal standard for quantification, (2) hydrolysis/ digestion of DNA, (3) enrichment of DNA adducts of interest (e.g., solid-phase extraction, immunoaffinity chromatography, or DNA repair enzymes),... 

Fig. 9 The relative amount of 6-hydroxyhexanoic acid (HHA) and 3-(2-hydroxyethoxy)-propanoic acid (HPA) formed during hydrolysis of a DXO/CL/DXO triblock copolymer, b CL/DXO multiblock copolymer, c Random crosslinked CL/DXO copolymer and d PCL homopolymer. All of the copolymers had 60 mol % CL imits and 40 mol % DXO imits. The polymers were hydrolyzed for different times in phosphate buffer pH 7.4 and 37 °C. After the predetermined hydrolysis times the monomeric degradation products were extracted by solid-phase extraction and analyzed by GC-MS. Reprinted from [160] with permission of American Chemical Society. American Chemical Society (2007)...

Moller, K., Crescenzi, C., and Nilsson, U., Determination of a flame retardant hydrolysis product in human urine by SPE and LC-MS. Comparison of molecularly imprinted solid phase extraction with a mixed mode anion exchanger. Anal. Bioanal. Chem., 378, 197-204, 2004. 

Recently, Blount et al. (2000) summarized a methodology to detect di- -butyl phthalate metabolites in urine. In humans or animals, di- -butyl phthalate is metabolized to mono- -butyl phthalate and oxidative products, which are excreted through the urine and feces. Human urine samples are processed by P-glucuronidase hydrolysis (to release the mono phthalate ester) followed by solid-phase extraction. The eluate is concentrated mono- -butyl phthalate is chromatographically resolved by reverse-phase HPLC, detected by negative ion atmospheric pressure chemical ionization (APCI) tandem mass spectrometry, and quantified by isotope dilution. 

A common procedure for the analysis of nitrofuran metabolites involves hydrolysis of the protein-bound metabolites under acidic conditions followed by deriva-tization with 2-nitrobenzaldehyde (Eig. 7.5). After neutralization of the digest, solvent extraction is carried out with ethyl acetate. Residues are detected by LC-UV or LC-MS/MS In some cases an additional liquid-liquid extraction or solid-phase extraction step is applied to remove excessive matrix compounds. A broad overview of applied methods was published by Vass et al. in 2008. ... 

Heroin and its metabolites can be isolated from human and animal biological fluids and tissues by various procedures including liquid-liquid and solid-phase extraction techniques. In order to prevent overestimation of 6-acetylmorphine resulting from the hydrolysis of heroin, heroin and 6-acetylmorphine standard curves can be prepared and extracted separately. Final results must be corrected for the percentage conversion of heroin to 6-acetylmorphine. 

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