Calibration Line Research Articles

Raman spectroscopy to determine CO2 solubility in mafic silicate melts at high pressure: Haplobasaltic, haploandesitic and approach of basaltic compositions

CO2 degassing of mafic silicate melts is an important part of the terrestrial carbon cycle, at mid-ocean ridges, oceanic hot spots, or in the middle of continents. Deeper CO2-bearing mafic magmas may also exist, such as those suspected in the D″ zone, and certainly existed in the magma ocean of the early Earth. Knowledge of the CO2 solubility in mafic melts at high pressure is therefore important but unknown at present. Results from molecular dynamics simulation (e.g., Guillot and Sator, 2011) predict that CO2 solubility in basalt may be much higher than previously thought at pressures and temperatures relevant to the upper mantle. But some recent models predict low solubility at high pressure (e.g., Eguchi and Dasgupta, 2018). The present study thus experimentally investigates the solubility of CO2 in basalt and andesite in the pressure range 1.5–8.5 GPa at 1820–2130 K in oxidizing conditions. Up to 4 GPa, the quenched samples are essentially vitreous and CO2-saturated. Their CO2 contents are measured using confocal micro-Raman spectroscopy, where we establish an internal calibration line relating CO2 content to the area of the Raman band assigned to the ν1 stretching vibration of carbonate groups. This calibration appears independent from the spectrometer, sample or experimentalist, thus enhancing confidence in this method. At 5 and 8.5 GPa, some of the quenched samples are found partially crystallized. Their CO2 abundance is estimated at micro-scale from Raman mapping, and at large scale from image analysis and presence/absence of vesicles. Over the 1.5–8.5 GPa pressure range, obtained CO2 concentrations vary between 1.8 and > 13.6 wt%. At 5 GPa and 1873 K, the CO2 content in basalt and andesite are similar. These findings experimentally confirm the ability of mafic melts to accommodate large amounts of CO2 at conditions prevailing in the deep Earth. A consequence is that magmas issued from partial melting of carbonate-bearing silicate rocks may ascend with significant quantities of CO2 of several wt% and more: when reaching shallower depths, they may degas large quantities of CO2. Present estimates of the global carbon flux to the atmosphere may thus be underestimated, and implications to early magma ocean degassing may be considered. Other consequences may concern the genesis of kimberlites and carbonatites. We finally speculate that, if silicate melts exist in the D″ zone, significant amounts of carbon may be stored there, and consequences may arise as to carbon sequestration in the core.

Measurement of respirable crystalline silica concentration by X-ray diffraction: Evaluation of metrological performances

Worker exposure to Respirable Crystalline Silica (RCS) is related with increased risk for lung cancer, so it is important to correctly assess it, through measurements of RCS. There are several methods for the uncertainty evaluation of the concentration of RCS measured by X-ray diffraction, however, none involves the calculation of the sensitivity coefficients of the mathematical measurement model. Hence, the aim of this research work is to propose an improved method, in which the sensitivity coefficients are calculated as partial derivatives of the model. The method was applied to four measurements campaigns in a factory, and the results seem to be comparable with those published in literature. It arose that for low concentrations the major contribution of uncertainty is due to the X-ray diffraction calibration line. This may mean that the minimum number of six calibration test filters, as suggested by the standards, is not sufficient, especially for low concentrations.

Investigation of Hybrid Methods for Elimination of Brilliant Blue Dye from Water Phase Using Various Nanomaterials Combined with Activated Sludge and Duckweed.

The main goal of this experimental work is screening of different natural and synthetic nanomaterials and biopolymers that may improve elimination of stable micropollutants from water phase. In this work, as a target chemical acting as the micropollutant molecule, the Brilliant Blue (BB) dye was selected. We tested different active matrices dispersed in water phase including activated carbon (AC), lyophilized graphene oxide (GO), β-cyclodextrin (CD), raw dandelion pappus (DP), microcrystalline cellulose(MC), and raw pine pollen (PP), as well as two types of Egyptian Blue mineral pigments (EB1 and EB2). Graphene oxide and Egyptian Blue nanomaterials were synthesized in our laboratory. We investigated potential application of such nanoparticles and biopolymer conglomerates as additives that may tune the activated sludge (AS) microorganisms or duckweed water plant (DW) and increase efficiency of micropollutants removal from wastewater. Studied nanomaterials/biopolymers were used in two different experimental modes involving real activated sludge microorganisms (24 h experiment) as well as duckweed plant (16 day experiment). Quantitative data of BB were obtained using microfluidic type device based on micro-TLC plate. This approach enabled direct determination of target component without sample pre-treatment like pre-concentration or pre-purification. Within single analytical run calibration line, retention standard spots (methyl red) and multiple samples were analyzed simultaneously. Due to the multivariate nature of these experiments, quantitative data were explored with chemometric tools including AHC (agglomerative hierarchical clustering), PCA (principal component analysis), and FA (factor analysis). Experimental data and multivariate calculations revealed that BB is strongly resistant on biodegradation, however, inclusion complexes formation with β-cyclodextrinmay induce degradation of this dye in the presence of duckweed. It is hoped that results of our experimental work can be used for designing of future experiments for fast screening of different additives and improvement of technological processes, focusing on purification of sewage and water from micropollutants.

CO2 effects on an unsaturated and saturated carbonate reservoir from geoelectric-geochemical coupling

The objective of this work is to understand and characterize how dissolved CO2 concentrations can influence physicochemical parameters, in particular the electrical conductivity and pH.In previous work, a CO2 injection experiment was carried out directly in a freshwater aquifer within an Oligocene carbonate underground quarry located in Saint-Emilion (Gironde, France). Different parameters emerged as excellent indicators for monitoring a gas plume during CO2 geological storage, especially the electrical conductivity and pH.We tried to reproduce field observations on a laboratory scale by batch experiments and measurements on Hassler cell, and to make the link between the geochemical results (electrical conductivity, pH, CO2 concentrations) and the electrical properties (electrical resistivity index) depending on the saturation state of the carbonate rock.A calibration line has been highlighted, making it possible to link the relation between electrical conductivity-CO2-pH. This line is only valid for Saint-Emilion limestones at the injection well because it is dependent on the petrophysical properties of the environment.As field observations are reproducible in the laboratory, this calibration line allows to pass from one scale to another by combining different results, and estimate the CO2 concentrations obtained for such values of electrical conductivity and pH.

Determination of carrageenan in jellies with new methylene blue dye using spectrophotometry, smartphone-based colorimetry and spectrophotometric titration

Carrageenan is a seaweed polysaccharide widely used as a food gelling and thickening agent. The New Methylene Blue dye was tested as an analytical reagent for the quantification of carrageenan in commercial jelly samples. The main spectral peaks of the dye decrease with increasing carrageenan-to-dye molar ratio up to 1. Three analytical procedures were tested: (i) spectrophotometric measurement at 590 nm, (ii) smartphone-based color measurement within the RGB color model and (iii) spectrophotometric titration at 625 nm. All the procedures provide straight calibration lines. Spectrophotometry provides better linearity as compared to smartphone-based colorimetry. Range of determination is dependent on type and purity of carrageenan. The spectrophotometric titration procedure provides lower values of limit of determination due to longer optical path used. Typical food additives used in jelly deserts do not interfere significantly with the proposed analytical approach.

Programmable flow injection in batch mode: Determination of nutrients in sea water by using a single, salinity independent calibration line, obtained with standards prepared in distilled water

Interference of the Schlieren effect on sea water analysis by spectrophotometry is caused by the flow of solutions of different ionic strengths through a flow cell. A flow injection assay protocol programmed in a flow-batch format removes this interference and allows the use of a calibration line, obtained in deionized water, for determination of analytes in sea water samples of different salinity. This Single Line Calibration (SLC) technique is validated on the most frequently performed nutrient assays. Automated determinations, performed at rates ranging from 20 to 60 samples/hr, covered seawater sample ranges from nM to mM with limits of detection: 12 nM for nitrite, 94 nM for nitrate, 47 nM for phosphate, and 240 nM for silicate. Reproducibility of the determinations was equal to or better than, 3% r.s.d. and day to day calibration was within 10%. The programmable FI, uses about 1/5th volume of reagents compared to continuous flow techniques.

Feasibility of Lead Exposure Assessment in Blood Spots using Energy-Dispersive X-ray Fluorescence.

Collecting blood spots from newborns is a common procedure used to diagnose multiple health conditions. Fingerstick blood samples are routinely collected from children to diagnose elevated blood lead levels. In our study, we wanted to test the feasibility of using a high-power energy-dispersive X-ray fluorescence (EDXRF) device to accurately measure the concentration of lead in blood spots. We created spotted standards of a known concentration of lead on a filter paper at different volumes and concentrations. We determined the detection limit for lead through repeated measurements of our standards and calibration line slopes. We also tested the variability of the measured lead concentration across procedures and spotted blood volumes and found no significant additions to uncertainty in measurements. Finally, we compared blood lead concentrations measured by EDXRF and atomic absorption spectroscopy (AAS) and found EDXRF to be a significant predictor of blood lead (n = 22, R = 0.98, p value <0.001) with an average detection limit of 1.7 μg/dL of blood lead. This detection limit is similar to that of the AAS technique, which is commonly used in clinical testing laboratories for blood lead surveillance. These findings provide a proof of concept that blood spots measured by EDXRF may be used as a surveillance tool for lead exposure, even at elevated blood lead levels of 2-3 μg/dL.

X-ray fluorescence analysis of major and trace elements in silicate rocks using 1:5 dilution glass beads

Thisreport describes analytical techniques for major and trace elements in silicate rocks by X-ray fluorescence (XRF) spectrometry. The analyzed elements are SiOz, Ti02, A1203, total Fe203, MnO, MgO, CaO, Na20, K20, P2Os, Sc, V, Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, La, Ce, Nd and Pb. All of these elements were determined on a single glass bead made from mixtures of 1 g of sample powder, 5 g of Li2B407 flux and about 50 mg of Lil releasing agent. A series of synthetic standard samples were prepared from pure chemical reagents to calibrate an XRF spectrometer. Matrix and line overlap corrections using a fundamental parameter approach yields reliable calibration lines with wide optimal ranges of composition. Analytical results of GSJ geochemical reference samples are in good agreement with their recommended values and exhibit sufficient precision and sensitivity for both major and trace elements.

Eliminating the need for craftsmanship: Facile and precise determination of oxygen reduction reaction activity by spraying catalyst ink on rotating disk electrode

Fabricating uniform catalyst thin films on rotating disk electrodes (RDEs) is crucial for the accurate and reproducible evaluation of the oxygen reduction reaction (ORR) activity of high surface area catalysts via the thin film (TF)-RDE method. For the conventional methods, a catalyst thin film is fabricated by drying one droplet of the catalyst ink on the surface of a glassy carbon (GC) disk electrode under the optimized conditions. However, the optimization of the drying conditions is time-consuming or sometimes impossible depending on the catalyst samples. In this study, we proposed a facile method of fabricating highly-uniform catalyst thin films using a commercial ultrasonic atomizer, which can forcibly deposit the catalyst particles evenly on the GC electrode. Although the catalyst loading is not precisely controlled by the atomizer, it can be determined using the total electrochemical surface area (ECSA) of Pt and a calibration line. By employing the developed method for two different commercial Pt/C catalysts, the ORR activities, which are comparable to the highest values reported in the previous literature, were obtained. Moreover, the developed method was also successfully applied to the ORR activity evaluation of a homemade Pt/NbB2 catalyst, which could not be properly tested by a conventional ink deposition method because of the difficulty of preparing a uniform catalyst thin film. Thus, the developed method eliminates the need for setting a specific film fabrication condition for each catalyst sample and enables the easy and precise ORR activity determination of any kind of high surface area catalyst as long as well-dispersed catalyst inks are available.

Leaf Wax Hydrogen Isotopes as a Hydroclimate Proxy in the Tropical Pacific

AbstractHydrogen isotope ratios of sedimentary leaf waxes (δ2HWax values) are increasingly used to reconstruct past hydroclimate. Here, we add δ2HWax values from 19 lakes and four swamps on 15 tropical Pacific islands to an updated global compilation of published data from surface sediments and soils. Globally, there is a strong positive linear correlation between δ2H values of mean annual precipitation (δ2HP values) and the leaf waxes n‐C29‐alkane (R2 = 0.74, n = 665) and n‐C28‐acid (R2 = 0.74, n = 242). Tropical Pacific δ2HWax values fall within the predicted range of values based on the global calibration, and the largest residuals from the global regression line are no greater than those observed elsewhere, despite large uncertainties in δ2HP values at some Pacific sites. However, tropical Pacific δ2HWax values in isolation are not correlated with estimated δ2HP values from isoscapes or from isotope‐enabled general circulation models. Palynological analyses from these same Pacific sediment samples suggest no systematic relationship between any particular type of pollen distribution and deviations from the global calibration line. Rather, the poor correlations observed in the tropical Pacific are likely a function of the small range of δ2HP values relative to the typical residuals around the global calibration line. Our results suggest that δ2HWax values are currently most suitable for use in detecting large changes in precipitation in the tropical Pacific and elsewhere, but that ample room for improving this threshold exits in both improved understanding of δ2H variability in plants, as well as in precipitation.

Square‐wave Voltammetry and Electrochemical Faradaic Spectroscopy of a Reversible Electrode Reaction: Determination of the Concentration Fraction of the Redox Couple

AbstractA comparative study conducted with square‐wave voltammetry (SWV) and electrochemical faradaic spectroscopy (EFS) is presented for a reversible electrode reaction of dissolved redox couple in the presence of both Ox and Red components. In agreement with previous studies, the net peak current ΔΨp of the theoretical SW voltammograms is positioned at the formal potential E0′ and does not depend on the concentration ratio c(Ox)/c(Red). However the forward‐to‐backward peak current ratio is sensitive to the redox state. For very low SW amplitudes, theoretical data imply superior features of EFS over SWV. Theoretical and experimental calibration lines are in good agreement within the interval 0.2≤x(Ox)≤0.8.

Geopolymer cement–modified carbon paste electrode: application to electroanalysis of traces of lead(II) ions in aqueous solution

Pb2+ ions were detected on a carbon paste electrode modified with a geopolymer cement. The X-ray pattern and the infrared spectrum of the geopolymer synthesized from metakaolin and phosphoric acid showed a three-dimensional semi-crystalline structure. The obtained geopolymer cement indicates the formation of a broad hump structure between 17 and 40° (2θ) ascribed to the poly(phospho-siloxo) network. The electroanalysis of Pb2+ ions was done in three steps by stripping voltammetry: accumulation of Pb2+ ions in open circuit at pH 4, detection in NaNO3 medium, and desorption. The peak current of Pb2+ ions obtained after 5-min accumulation on the geopolymer cement–modified carbon paste electrode was found to be four times higher than that from the bare carbon paste electrode. After optimization of some parameters related to the detection process (geopolymer cement content in paste, accumulation time, pH of detection medium, detection medium, electrolysis time, potential electrode), a calibration line was drawn in the concentration range from 0.2 × 10−6 M to 1.4 × 10−6 M. The detection limit obtained from a signal-to-noise ratio equal to 3 is 2.3 × 10−9 M. The interferences of some heavy metal ions, such as Hg2+, Cd2+, and Cu2+, and some inorganic ions Al3+, Fe2+, Zn2+, Na+, K+, Ca2+, Mg2+, Cl−, SO42−, and NO3− on CPE/GP-Dib2 sensor were examined. The results obtained shows that these inorganic ions did not interfere with the determination of Pb2+ ions. It indicated that the prepared sensor possessed high selectivity for Pb2+.

Ethanol concentration and calorific value of some local distilled Ethiopian alcohol (Areki): an energy potential assessment

This paper deals with determination of the ethanol concentration and its heating value (calorific value in local distilled Ethiopian Areki, which is extracted from Maize, Dagussa (Sorghum) and Gibto (Lupin). The primary target of this paper is assessing the energy potential of some locally produced Ethiopian alcohols by identifying the major parameters like ethanol concentration, calorific value and its acidity. The samples of Areki were prepared in one of the vending houses in Injibara Ethiopia and raw material used for their preparation was measured before preparation. The levels of ethanol concentration among the sample were determined using a UV/vis spectrophotometer. After calibrating with a standard sample (benzoic acid), the GCV of the alcohol samples was determined experimentally using an oxygen bomb calorimeter (IKA® Model C200 bomb Calorimeter). The quantitative analysis of ethanol in the sample was done by preparing an aqueous solution of ethanol to draw by means of absorbance versus concentration calibration line at a wavelength of 986 nm. The investigation shows that maximum and minimum percentages of ethanol concentration (%v/v) in the samples were found for dagim maize (50.17%) and dagim lupin Areki(26.64%), respectively. The gross calorific value of local distilled areki ranges from 6.616 MJ/kg-13.1432 MJ/kg. The highest GCV was obtained by dagim maize alcohol due to the higher ethanol content and dagim lupin alcohol with a small ethanol concentration has the lowest GCV. According to the findings, dagim alcohols extracted from sorghum and maize have high potential energy and can be blended with other fossil fuels with little purification.

Detection of adulteration of traditional Slovak bryndza ewe’s cheese with cow’s lump cheese by isoelectric focusing of gamma caseins

ABSTRACT “Slovak bryndza” is a traditional Slovak cheese manufactured by milling a lump of matured ewe’s cheese or by milling a mixture of lump ewe’s cheese and lump cow’s cheese. The percentage of lump ewe’s cheese is greater than 50% w/w dry matter. Differences in the purchase prices of ewe’s and cow’s milk create the potential for adulteration. The detection of cow’s milk compounds by isoelectric focusing of γ-caseins after plasmolysis is a suitable method for the determination of adulteration of this traditional cheese. The analysis and final results may be affected by factors affecting laboratory activity and biological factors. Biological factors are manifested primarily as variations in the casein content of ewe’s and cow’s milk. Despite this variation, this method may also be used for quantification purposes. We were able to establish a reliable calibration line from the internal reference materials prepared in our laboratory. The mean composition of Slovak bryndza cheese determined in our research was protein 18.7 ± 1.9 g 100 g−1, fat 24.0 ± 1.8 g 100 g−1, lactose 1.5 ± 1.9 g 100 g−1, ash 4.5 ± 0.3 g 100 g−1, fat in dry matter 49.3 ± 2.6 g 100 g−1, casein 18.4 ± 1.9 g 100 g−1, gamma casein 0.60 ± 0.19 g 100 g−1, and bovine-to-ovine gamma casein ratio 0.65 ± 0.12 g 100 g−1.

Adaptive Filtering Method of MFL Signal on Rail Top Surface Defect Detection

Magnetic flux leakage (MFL) detection technology provides an effective method to conduct high-speed detection of the damage suffered by rail surface. With regard to high-speed detection, there is frequently a complex noise contained in the magnetic signal of railway leakage, which is similar to the amplitude of defect and the overlaps of frequency spectrum. In this paper, an improved adaptive filtering method is proposed to solve the problem caused by filtering the MFL signal on the rail top surface. Through the characteristics of distribution shown by defects on the top surface of the railway and those of the data collected by the rail top array sensor, this method is applied to construct a virtual channel containing almost only interference signals but no defects. Then, in combination with the adaptive filtering algorithm, the virtual channel signal is taken as the reference input of the adaptive canceller, each single channel MFL signal is taken as the original input of the adaptive canceller, and the filtered MFL signal is taken as the output. Then, the MFL signal of rail top is collected by the train at the speed of 30km / h on the manual calibration line. According to the experimental results, the noise intensity of MFL signal is reduced by up to 81.44%. In addition, the filtering method is adopted to process MFL signals with different directions and varying detection speed. As indicated by the results, the noise intensity of MFL signal is reduced by more than 74%.

Impact of Pasteurization on Ascorbic Acid in Orange Juice (Overview)

Loss in Ascorbic Acid contents of orange juice heated under different situations and pH was researched. In this experiment, Navanila oranges from Spain were squeezed and filtered by using a vacuum pump to make orange juice samples. These samples were extracted and make up with 0.1% Formic Acid in HPLC water, HPLC water and phosphate buffer solution (pH=6). Pasteurization was achieved at 60, 65 and 70℃ over 15, 25 and 35min period by using the water bath method and cooled to room temperature immediately. After that, Ascorbic Acid contents were analyzed by HPLC and 0.1% Formic Acid in HPLC water, HPLC water and phosphate buffer solution (pH=6) were used as mobile phases separately for their solutions. HPLC standard samples of Ascorbic Acid were prepared which means 0.1g Ascorbic Acid was weighted and then diluted into 50-250mg/ L solutions to make calibration lines for three solutions. The wavelength of Ascorbic Acid was 245nm but it changed to 296nm when samples in phosphate buffer solution (pH=6). Results showed that Ascorbic Acid concentration is more at 60℃ at 15min and there was a total decline trend with the increase of time and temperature. After statistics analysis, it has a significant affect (P&amp;lt;0.5) related to Ascorbic Acid contents with temperature and pH.

FT-IR/ATR Solid Film Formation: Qualitative and Quantitative Analysis of a Piperacillin-Tazobactam Formulation

FT-IR/ATR analytical technique is one of the most applicable techniques worldwide. It is closely associated with easy-to-use equipment, rapid analysis, and reliable results. This study reports the simultaneous qualitative and quantitative analysis of two active pharmaceutical ingredients (APIs), of a piperacillin and tazobactam formulation using a film formation method. This method requires film formation on the ATR crystal, resulting from solvent evaporation of a small amount of liquid sample. Good contact between the film and the crystal led to the identification of both APIs, although tazobactam was of low content in the formulation mixture. The quantification of the APIs in the commercial mixture was also achieved, using a single calibration line with a correlation coefficient equal to 0.999, not only after film formation but also in the initial dry formulation before reconstitution. The present spectroscopic technique combined with the proposed relatively simple sample treatment outweighs chromatographic protocols already applied, which require specialized staff and are costly, time-consuming, and not environmentally friendly. Taking all the above into consideration, it turns out that such an approach has the potential to be used for off-line quality control procedures in manufacture or, in terms of portable equipment and automated software, anywhere for on-site analysis, even in a hospital workflow.

Development of the MICADO Flat-field and Wavelength Calibration Unit: From Design to Prototyping

We describe the evolution and the analysis of the design that led to the development of the Flat-field and wavelength Calibration Unit (FCU) for the Multi-AO Imaging CAmera for Deep Observations (MICADO) instrument. MICADO will be one of the first light instruments of the Extremely Large Telescope. The FCU challenge in terms of calibration is related to the large size of the MICADO entrance and final focal plane, ∼200 mm × 200 mm. Such a focal plane scale and its segmentation in 3 × 3 detectors, require significant design modifications with respect to the calibration units of the current and past generation of instruments. The design analysis and ray tracing calculations are complemented with the test and verification of lab prototypes to assess the reliability of the FCU architecture in terms of flat-field illumination uniformity and signal to noise, spectral calibration line coverage and radial velocity stability of the wavelength solution provided to the instrument.

Indoor Positioning Method Using WiFi RTT Based on LOS Identification and Range Calibration

WiFi-based indoor positioning methods have attracted extensive attention due to the wide installation of WiFi access points (APs). Recently, the WiFi standard was modified and introduced into a new two-way approach based on round trip time (RTT) measurement, which brings some changes for indoor positioning based on WiFi. In this work, we propose a WiFi RTT positioning method based on line of sight (LOS) identification and range calibration. Given the complexity of the indoor environment, we design a non-line of sight (NLOS) and LOS identification algorithm based on scenario recognition. The positioning scenario is recognized to assist NLOS and LOS distances identification, and gaussian process regression (GPR) is utilized to construct the scenario recognition model. Meanwhile, the calibration model for LOS distance is presented to correct the measuring distance and the scenario information is utilized to constrain the estimated position. When there is a positioning request, the positioning scenario is identified with the scenario recognition model, and LOS measuring distance is obtained based on the recognized scenario. The LOS range measurements are first calibrated and then utilized to estimate the position of the smartphone. Finally, the positioning scenario is used to constrain the estimation location to avoid it beyond the scenario. The experimental results show that the positioning effect of the proposed method is far better than that of the Least Squares (LS) algorithm, achieving a mean error (ME) of 0.862 m and root-mean-square error (RMSE) of 0.989 m.

The validation of immunoblot SDS-PAGE as a qualitative and quantitative method for the determination of urinary Cystatin C in neonates

IntroductionThe quantitative determination of urinary Cystatin C (cyst-C) associated with the qualitative analysis of its polymorphisms is an excellent method for early identification of newborns predisposed to renal function impairment. PETIA, PENIA and EIA are the immunometric methods used for the quantitative determination of cyst-C in human biologic fluid but they have limitations and do not allow qualitative analysis. The present study is a validation of Immunoblot SDS-PAGE for the qualitative and quantitative analysis of urinary cyst-C. MethodsUrine was collected from neonates in the nursey at S. Maria della Misericordia Hospital. Urinary cyst-C was investigated by the immunoblot SDS-PAGE and by reading of optical density. ResultsThe qualitative analysis showed two different molecular forms: a reactivity at about 70 KDa in all samples and a reactivity at 13 KDa in a limited number of samples. This analysis allows the correlation of the polymorphisms of cyst-C with specific alterations of renal function in newborns. The quantitative analysis is specific, sensitive and accurate.In fact the coefficient of variation for assay precision was 10% and for assay accuracy was ±10%, the detection limit was 0.009 ng/ µL and the calibration line has satisfactory linearity (range 0.02–0.3 ng/ µL). The stability of urinary cyst-C was acceptable, even without the use of protease inhibitors, as long as the assay was performed on freshly recruited urine or immediately after thawing the samples, which had been stored for up to six months. ConclusionImmunoblot SDS-PAGE analysis is a valid method of obtaining a qualitative and quantitative analysis of urinary cyst-C. This method presents unique information about a previously unknown 70 KDa cyst-C form. The assay may offer potential diagnostic information not available with immunometric method.