Afterglow Amplification for Fast and Sensitive Detection of Porphyria in Whole Blood

Porphyria is a group of genetic photodermatoses that cause too much porphyrin to accumulate in the blood, skin, and liver, resulting in skin photosensitivity and damage, liver disease, or potential liver failure. Conventional detection methods include high-performance liquid chromatography and fluorescence spectrometry. However, these methods usually require complicated pretreatment and time-consuming processes. Therefore, efficient and fast detection of porphyria is urgently needed. Herein, we develop a molecular afterglow reporter-based sensing scheme for the detection of porphyrins in whole blood. The afterglow reporter can respond to the production of singlet oxygen (¹O₂) of porphyrins after light excitation, and the detection signals can be amplified through adjusting the amount of singlet oxygen and afterglow reporter molecules. Moreover, without the use of a real-time excitation source, afterglow signals can avoid the scattering and autofluorescence interference in biological samples, thereby reducing background noise. More importantly, we prove the applicability of the afterglow reporter in the quantitative detection of porphyrins in whole blood and demonstrate its great clinical potential.

A simple and rapid fluorimetric method for simultaneous determination of protoporphyrin IX and zinc protoporphyrin IX in whole blood

Derivative variable-angle synchronous fluorescence (DVASF) spectrometry improves the spectral resolution and selectivity of the fluorescence method. The feasibility of DVASF spectrometry for the simultaneous determination of protoporphyrin IX (PP) and zinc protoporphyrin IX (ZnPP) was investigated. PP and ZnPP were distinguished from each other simultaneously and rapidly by the DVASF method. The spectra were resolved well, and the two components were determined in a single scan, avoiding the spectral compensation factor for PP and chromatographic separation. The linear range of the calibration curve for PP was from 0.190 to 152 nmol/L and for ZnPP was from 0.383 to 230 nmol/L. The detection limits of PP and ZnPP were 0.098 nmol/L and 0.088 nmol/L, respectively. The within-run imprecision (RSD, n = 5) for PP was 4.1%, and for ZnPP was 4.2%. Mean recoveries (SD) of PP and ZnPP added to a blood sample were 86.4 (7.3)% and 72.9 (6.6)%, respectively. This method should be a potential tool in the rapid routine screening of large quantities of samples.

Application of ion pair high performance liquid chromatography to the analysis of porphyrins in clinical samples

Reversed phase ion pair chromatography is a highly selective separation technique for the determination of free porphyrin carboxylic acids from human materials. Isocratic and gradient elution methods can be used to analyse porphyrin isomers and to establish porphyrin profiles for the biochemical diagnosis of porphyrias. Ion pair high performance liquid chromatography led to the discovery of the atypical isomers II and IV of uroporphyrin and coproporphyrin in human urine. Advantages and limitations of the ion pair technique are discussed.

Determination of erythrocyte porphyrins by reversed-phase high-performance liquid chromatography using capsule-type silica gels coated with silicone polymer

A simple, rapid and reliable method is described for determining erythrocyte porphyrins using a new type of reversed-phase silica whose surface is coated with silicone polymer. After a single-step extraction of blood with N,N-dimethylformamide, zinc protoporphyrin IX and protoporphyrin IX were separately quantified in a single run in 5 min. The column life was so long that no alteration in elution profile or retention time was apparent after 1500 injections of samples. The method described would be useful for the screening of lead exposure or iron-deficiency anaemia, and also for the diagnosis of erythropoietic protoporphyria.

High-performance liquid chromatography of porphyrins

Techniques for the analysis of porphyrins in the biomedical fields are reviewed. The emphasis is on high-performance liquid chromatography and its aspplications in: (1) the quantitative analysis of porphyrins in blood, urine and faeces; (2) qualitative porphyrin profiles in normal subjects and in the porphyrias; (3) assay of haem biosynthetic enzyme activities and (4) resolution of type isomers of porphyrins and porphyrinogens. Detection systems, quantitation methods, peak identification and sample preparation procedures are discussed.

Separation of metalloporphyrins from metallation reactions by liquid chromatography and electrophoresis

The analytical separation of the indium and manganese complexes of three synthetic, meso-substituted, water-soluble porphyrins from their respective free bases in metallation reaction mixtures is described. The ligands tetra-3N-methylpyridyl porphyrin, tetra-4N-methylpyridyl porphyrin and tetra-N,N,N-trimethylanilinium porphyrin are complexed with In (III) and Mn (III) and are separated from residual free base by high-performance liquid chromatography (HPLC) in acidic conditions with gradient elution on ODS bonded stationary phase. Electrophoretic separation is achieved on both cellulose polyacetate strips and polyacrylamide tube gels under basic conditions. Although analytical separations can be achieved by both HPLC and electrophoresis, only HPLC is suitable for the development of preparative scale separations. Column chromatography, ion-pairing and ion-suppression HPLC techniques fail to separate such highly charged and closely related aromatic compounds.

Tissue porphyrin pattern determination by high-speed high-performance liquid chromatography

A rapid and sensitive method for the determination of porphyrin carboxylic acids in liver, kidney, and spleen by high-speed high-performance liquid chromatography is described. Porphyrins were extracted with recoveries greater than or equal to 98%, concentrated on disposable octadecylsilyl cartridges, and analyzed with a liquid chromatograph equipped with a 3 microns X 3 cm octadecylsilyl column and a fluorescence detector. Separation of di-, tetra-, penta-, hexa-, hepta-, and octacarboxylic acids was achieved within 5 min. The detection limits for uro, copro, and protoporphyrin were 20, 10, and 20 fmol, respectively.

Determination of porphyrins by high performance liquid chromatography: fluorescence detection compared to absorbance detection

A comparison is made between determination of porphyrin methyl esters by high performance liquid chromatography (HPLC) with absorbance detection and with fluorimetric detection. Detection limits with absorbance detection vary from 0.8 pmol for 2-COOH-porphyrins to 5 pmol for 8-COOH-porphyrins. With fluorometric detection the corresponding figures are 0.04 pmol and 0.4 pmol. Fluorimetric detection also has a better reproducibility, and it is more specific than absorbance detection. The use of HPLC with fluorimetric detection thus permits rapid, highly efficient and specific quantitative detection and identification of porphyrins in complex biological samples.

Improved separation and detection of free porphyrins by high-performance liquid chromatography

Porphyrins were separated using ion-pair reversed-phase high-performance liquid chromatography. The eluents were aqueous potassium phosphate buffer and tetrabutylammonium phosphate in methanol. The influences of pH value and ionic strength of the phosphate buffer and molarity of the ion-pair reagent in methanol were investigated to improve separation and detection. A linear response curve was obtained from 0.38 to 7.64 pmol for coproporphyrin I. The detection limits were determined to be 0.12 pmol for coproporphyrin I and 0.22 pmol for uroporphyrin I.

The laboratory evaluation of microcytic red blood cells

Microcytic red blood cell states are common clinical problems in both adult and pediatric age groups. The recent widespread availability of electronic blood cell counters for performing routine blood counts has increased the detection of microcytic red blood cells. Physicians must workup both symptomatic and asymptomatic patients with microcytic red blood cells before they can initiate proper therapy and/or counseling. The purpose of this review is threefold: (1) to discuss the causes of microcytic red blood cells in terms of disorders of decreased heme production vs. disorders of decreased globin production, (2) to review the clinical laboratory tests useful in differentiating microcytic red blood cell states, and (3) to present a practical approach for the laboratory workup of microcytic red blood cells.

The rapid determination of erythrocyte porphyrins using reversed-phase high performance liquid chromatography

The extraction, separation and quantification of free acid erythrocyte porphyrins are described. The porphyrins are extracted from whole blood using 3:1 ethyl acetate/acetic acid (v/v) and separated using the reversed-phase mode of high performance liquid chromatography (RPLC). The compounds are detected on-line spectrofluorometrically using an excitation wavelength of 404 nm and an emission cut-off filter of 550 nm. Excellent resolution of the porphyrin free acids is achieved in less than 6 min. The analytical recoveries for protoporphyrin IX and zinc protoporphyrin IX were greater than 90% with relative standard deviations for day-to-day analysis under 6%.