CO2 gap changes compared with cardiac output changes in response to intravenous volume expansion and/or vasopressor therapy in septic shock.

Background: The difference in partial pressure of carbon dioxide (PCO2) between mixed or central venous blood and arterial blood, known as the ∆PCO2 or CO2 gap, has demonstrated a strong relationship with cardiac index during septic shock resuscitation. Early monitoring of the ∆PCO2 can help assess the cardiac output (CO) adequacy for tissue perfusion. Objectives: To investigate the value of ∆PCO2 changes in early septic shock management compared with CO. Methods: This observational prospective study included 76 patients diagnosed with septic shock admitted to Cairo University Hospital's Critical Care Department between December 2020 and March 2022. Patients were categorised by initial resuscitation response, initial ∆PCO2 and 28-day mortality. The primary outcome was the relationship between the ∆PCO2 and CO changes before and after initial resuscitation, with secondary outcomes including ICU length of stay (LOS) and 28-day mortality. Results: Peri-resuscitation ∆PCO2 changes predicted a ≥15% change in the cardiac index (CI) (area under the curve (AUC) 0.727; 95% CI 0.614 - 0.840) with 66.7% sensitivity and 62.8% specificity. The optimal ∆PCO2 change cut-off value was <-1.85, corresponding to a <-22% threshold for a 15% cardiac index increase. The PCO2 gap ratio (gap/gap ratio of T1- PCO2 gap to T0 -PCO2 gap) also predicted a ≥15% change in cardiac index (AUC 745; 95% CI 0.634 - 0.855) with 63.6% sensitivity and 79.1% specificity. The optimal CO2 gap/gap ratio cut-off value was <0.71. A significant difference in 28-day mortality was noted based on the gap/gap ratio. Conclusion: Peri-resuscitation ∆PCO2 and the gap/gap ratio are useful non-invasive bedside markers for predicting changes in CO and preload responsiveness. Contribution of the study: The current study provides an insight to the PCO2 gap changes during and after early resuscitation of septic shock patients, which correlate to cardiac output changes and might also serve as a fluid responsiveness indicator.

Development and Validation of a Modified QuEChERS protocol Coupled to Liquid Chromatography-Tandem Mass Spectrometry for the Rapid and Accurate Determination of Acrylamide in Cereal-Based Baby Foods.

BACKGROUND: With the widespread consumption by children of cereal-based baby food, acrylamide contamination is a prevalent risk that may have carcinogenic consequences. OBJECTIVE: This study aims to develop and validate a modified QuEChERS protocol (quick, easy, cheap, effective, rugged, and safe) without solvent exchange, followed by rapid separation and accurate determination of acrylamide in cereal-based baby foods using reversed-phase (RP)-LC-MS/MS. METHODS: Samples were extracted using a modified QuEChERS protocol of the AOAC version and cleaned up with basic alumina. Separation was performed on a Phenomenex® Kinetex C18 column (100 Å × 3.5 µm × 4.6 mm × 150 mm) using a gradient elution program with a mobile phase of 10 mM ammonium formate-methanol. Determinations were conducted using electrospray ionization (ESI)-MS/MS in positive-ion mode. RESULTS: Basic alumina yielded clean extracts, resulting in acceptable recovery percentages and a tolerable matrix effect (ME) <5%. This allowed extraction without a solvent exchange step. Efficient separation was achieved at a retention time (tR) of 3.39 ± 0.05 min employing an RP-C18 column with core-shell properties in a relatively short analysis run time of only 5 min. Trueness, precision, LOD, LOQ, linearity range, and R2 results were 92.5-104.6%, RSD ≤12.2%, 5 µg/kg, 20 µg/kg, 4.0-1000.0 µg/kg, and > 0.9999, respectively. The test method applicability was demonstrated by proficiency testing (PT) and 50 real samples of cereal-based baby foods. Most of the tested samples were in violation of acrylamide's established European Union benchmark (40 µg/kg). CONCLUSION: Acetate-buffered QuEChERS protocol in conjunction with optimized amounts of basic alumina was confirmed as an efficient extraction protocol for acrylamide from cereal-based baby foods resulting in optimal method performance. Successful selection of the RP-C18 column is key for selective separation for acrylamide in a relatively short analysis run time. HIGHLIGHTS: The modified AOAC QuEChERS protocol with a dispersive solid phase extraction (d-SPE) of basic alumina assisted in reducing the ME to tolerable levels while maintaining acceptable method performance. The use of an RP-C18 column with core-shell properties enabled a rapid and accurate acrylamide determination.

Fungal treatment for liquid waste containing U(VI) and Th(IV).

Four fungal and one bacterial isolates were isolated from a liquid waste sample of Nuclear Material Authority. Those dried biomasses were screened for uranium (U) and thorium (Th) adsorption efficiency where the most potent isolate was identified according to sequence similarities and phylogenetic analysis as Aspergillus niger LBM 134. Using U or Th synthetic solutions many factors were investigated for controlling the biosorption process to conduct the optimum process conditions (the solution pH, contact time, elemental initial concentration, biomass dosage, and sorption temperature). A. niger LBM 134 dried biomass was examined ESEM-EDX and the FTIR techniques before and after the sorption process, also the data were handled by different kinetics and isothermal models. Application on the real liquid waste revealed that the bio-uptake capacities were 18.5 and 11.1 mg/g for U and Th respectively.

Polyvinylpyrrolidone-Aminopropyl-SBA-15 schiff Base hybrid for efficient removal of divalent heavy metal cations from wastewater.

The mesoporous silica-polymer hybrid was prepared as an adsorbent for divalent heavy metals (Pb(II), Ni(II), and Cu (II)) from rice husk and polyvinylpyrrolidone (PVP) through three successive steps. The first is the preparation of the mesoporous silica (SBA-15), the second is grafting 3-aminopropyltrimethoxysilane on SBA-15, and the following step is the formation of Schiff base (PVP-SBA-15) between amine end-capped silica and PVP moieties. The materials were characterized by different techniques, including FTIR, low and wide-angle XRD, N2-adsorption, and HR-TEM. The NH2-SBA-15 displayed a moderate affinity toward heavy element ions under study. Grafting of PVP moieties introduces a high affinity toward heavy metal ions, and the adsorption is a well-fitted Langmuir adsorption model. A series of experiment adsorption equilibrium reported with SBA-15, NH2-SBA-15, and PVP-SBA-15, which showed an adsorption capacity of 128 mg/g (Cu (II)), 175 mg/g (Pb (II)) and 72 mg/g for Ni(II). Kinetic studies have shown that the best way to describe the adsorption process of heavy metals is pseudo-first-order. The value of ΔG°, ΔH°, and ΔS° demonstrated that the adsorption of heavy metals on the PVP-SBA-15 was endothermic in nature and spontaneous. These results exhibited that PVP-SBA-15 material has considerable competence in eliminating heavy metals from wastewater.

Glauconite clay-functionalized chitosan nanocomposites for efficient adsorptive removal of fluoride ions from polluted aqueous solutions.

We herein have developed a mild approach for the fabrication of glauconite clay (G)-modified chitosan (CS) nanocomposites by the combination of a simple blending and crosslinking method. The chitosan was modified with ethylenediaminetetraacetic acid (EDTA), glutaraldehyde (GL), sodium dodecyl sulfate (SDS), and cetyltrimethyl ammonium bromide (CTAB). The as-prepared composites were identified using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), nitrogen physical adsorption (BET), atomic absorption spectrophotometry (AA), and thermal gravimetric analysis (TGA). The adsorption activities of the as-prepared materials were assessed for the removal of fluoride ions from aqueous media using a batch technique. Raw glauconite (G), GL-CS/G, SDS-CS/G, EDTA-GL-CS/G, and CTAB-CS/G adsorbents displayed maximum adsorption capacity values of 1.15, 4.31, 4.55, 6.90, and 9.03 mg g-1, respectively. The adsorption results were well described by employing the pseudo-second-order kinetic and Langmuir isotherm models. The estimated thermodynamic constants indicated that the F- ion adsorption was a spontaneous, physisorption process. Furthermore, the modified chitosan adsorbents are good candidates for the adsorptive elimination of F- ions from aqueous solutions, according to their reusability, high stability, good adsorption capacity, and applicability for actual field water samples.

PCDD/PCDFs and PCBs in the irrigation water in Egypt: levels, patterns, and potential sources.

The contamination levels of PCDD/PCDFs in irrigation water are the most rarely studied throughout the world. The major problem in Egypt is the lack of studies and statistics about these contaminants of POPs in irrigation water. Therefore, this study is the first comprehensive report to elucidate the estimation and sources of PCDD/PCDFs and PCBs in irrigation water from Egypt and rare for worldwide may provide a reference to future studies of POPs compounds in irrigation water of Egypt. A total of 24 irrigated water samples were collected from different irrigation canals which are adjacent to industrial areas from six Egyptian governorates (Bani Swef, El-Giza, El-Sharkeya, El-Menoufeya, El-Gharbeya, and Alexandria). The study shows that irrigation water canals were contaminated with low levels of PCDDs/PCDFs, which were 0.95 pgWHO-TEQ/l, and the total of PCDD/PCDFs and dl-PCBs were 2.06 pgWHO-TEQ/l with contamination ranging between 0.88 to 2.97 pgWHO-TEQ/l while the levels of indicator PCBs were 18.52 ng/l and ranged between 0.39 to 165.6 ng/l. The most predominant dioxins congeners were HpCDD, OCDD, HpCDF, and OCDF while for dl-PCBs were PCB105 and PCB118, and for ndl-PCBs was PCB138. The areas with recent urbanization and industrialization were more contaminated with PCBs than the unindustrialized area. Lightly to moderately chlorinated congeners dominated the PCB profiles. The major sources for these contaminants were fire bricks followed by textile industries closer to the located sampling sites. The detected pattern was found to be similar to the patterns reported in the air by other studies. Although the concentrations of the studied POPs are found to be low in irrigated water, it may be considered as a potential source of soil pollution due to their accumulation process in the agricultural land and may lead to risk on human health by consuming the agricultural products irrigated by contaminated water.

Use of isotope hydrology in groundwater conceptualization for modeling flow and contaminant transport at northwestern Sinai, Egypt.

The study area extends along northwestern Sinai coastal plain, which is considered an integral part of the Mediterranean Sea. It depends mainly on the groundwater resource for different type of human activities such as agricultural and drinking. Many programs and policies should be implemented in this area to concurrently improve the sustainability of groundwater use and manage the risks of its degradation. Leakage from some factories in Bir El-Abd might be a contamination source that would threaten groundwater. In this paper, an attempt was made using an integrated approach of the hydrogeological setting and the conjugation of the hydrogeochemical data with the stable isotope hydrology for representation of the conceptual model of the study area. Those tools give more insights on the characterization of the groundwater system with all relevant boundaries and main recharge sources of the aquifer; which is considered to be the key components of a groundwater modeling. A particular focus is placed on modeling a hypothetical accident for contaminant transport in the groundwater system, using both lead and chromium as a typical contaminant component. Further predication of the concentration of those elements has been estimated, and the safety distances of their plume have been determined. This study would be helpful in dealing with water management issues related to contaminant hydrogeology. As well, it introduces some finding for reducing the environmental risk form the industrial development at the study area.

Hydrochemical and multivariate analysis of groundwater quality in the northwest of Sinai, Egypt.

The northwestern coast of Sinai is home to many economic activities and development programs, thus evaluation of the potentiality and vulnerability of water resources is important. The present work has been conducted on the groundwater resources of this area for describing the major features of groundwater quality and the principal factors that control salinity evolution. The major ionic content of 39 groundwater samples collected from the Quaternary aquifer shows high coefficients of variation reflecting asymmetry of aquifer recharge. The groundwater samples have been classified into four clusters (using hierarchical cluster analysis), these match the variety of total dissolvable solids, water types and ionic orders. The principal component analysis combined the ionic parameters of the studied groundwater samples into two principal components. The first represents about 56% of the whole sample variance reflecting a salinization due to evaporation, leaching, dissolution of marine salts and/or seawater intrusion. The second represents about 15.8% reflecting dilution with rain water and the El-Salam Canal. Most groundwater samples were not suitable for human consumption and about 41% are suitable for irrigation. However, all groundwater samples are suitable for cattle, about 69% and 15% are suitable for horses and poultry, respectively.

Assessment of groundwater quality using geographical information system (GIS), at north-east Cairo, Egypt.

The present investigation has been conducted to delineate the hydrogeochemical and environmental factors that control the water quality of the groundwater resources in the north-east of Cairo. A complementary approach based on hydrogeochemistry and a geographical information system (GIS) based protectability index has been employed for conducting this work. The results from the chemical analysis revealed that the groundwater of the Quaternary aquifer is less saline than that of the Miocene aquifer and the main factors that control the groundwater salinity in the studied area are primarily related to the genesis of the original recharging water modified after by leaching, dissolution, cation exchange, and fertilizer leachate. The computed groundwater quality index (WQI) falls into two categories: fair for almost all the Miocene groundwater samples, while the Quaternary groundwater samples are all have a good quality. The retarded flow and non-replenishment of the Miocene aquifer compared to the renewable active recharge of the Quaternary aquifer can explain this variation of WQI. The index and overlay approach exemplified by the DUPIT index has been used to investigate the protectability of the study aquifers against diffuse pollutants. Three categories (highly protectable less vulnerable, moderately protectable moderately vulnerable and less protectable highly vulnerable) have been determined and areally mapped.

The effect of triiodothyronine on maturation and differentiation of oligodendrocyte progenitor cells during remyelination following induced demyelination in male albino rat.

Demyelination was induced by two weeks cuprizone treatment. Rats of +ve control and triiodothyronine (T3) then received three subcutaneous injections of either saline or T3 day after day and sacrificed at the end of the third and fifth weeks. Animals in -ve control group received only standard rodent chow. After one week of cuprizone withdrawal the corpus callosum in +ve control and T3 treated rats was still demyelinated as revealed by MBP immunohistochemistry. The assay of PLP gene showed significant increase of T3 treated group compared to both the -ve control and +ve control groups. After three weeks, significant improvement in myelination was detected in T3-treated group compared to +ve control as detected by both MBP immunohistochemistry and electron microscopy. After one week of cuprizone withdrawal, PDGFRα positive cells and gene expression showed significant increase in +ve control and T3-treated groups as compared to -ve control with insignificant difference in between the former two groups. After three weeks of cuprizone withdrawal, PDGFRα positive cells in T3-treated and +ve control groups decreased to the control levels. These results suggest that T3 was effective in improving remyelination when administered during acute phase and might direct progenitor lineage toward oligodendrocytes.

On-line Determination of Zinc in Water and Biological Samples after Its Preconcentration onto Zincon Anchored Polyurethane Foam.

A fast and sensitive on-line procedure for the determination of zinc in water and biological samples was developed. Zinc was preconcentrated in a mini-column packed with polyurethane foam (PUF) chemically modified with zincon via -N=N- bonding. The optimal conditions for preconcentration were pH 8.5 and sample flow rate of 4.0 mL min(-1). Quantitative desorption of Zn(II) was obtained by 0.1 mol L(-1) hydrochloric acid and subsequent spectrophotmetric determination using 4-(2-pyridylazo)-resorcinol at 498 nm. The obtained detection limit was found to be 3.0 ng mL(-1), precision (RSD) was 4.8 and 6.7% at 20 and 110 ng mL(-1), respectively, for 60 s preconcentration time and enrichment factor was 31. The linearity range was from 10 to 120 ng mL(-1) and maximum sample throughput was 20 h(-1). Finally, the method was successfully applied to the determination of zinc in tap water, Nile River water and human urine samples with RSD in the range of 1.1 - 8.3%.

Physicochemical studies of the reaction of (99m)Tc with 5,5'-diethyl barbituric acid, adenine, d-glucose and thiobarbituric acid at different temperatures.

The reaction of (99m)Tc pertechnetate with 5,5'-diethyl barbituric acid, adenine, d-glucose and thiobarbituric acid at different temperatures was studied. The solvent effect on the electronic absorption spectra of the reactions was recorded. The reaction mixtures have been analyzed at different times using TLC and a radiodetctor to show the peaks at the plates. (99m)Tc pertechnetate is obtained from the Mo generators. It is difficult to separate the complexes in the solid state. The percentage of (99m)Tc involved in the complexes can be determined. Characterization of the (99m)Tc complexes as well as the determination of the extent of radiolabeling was done by thin layer chromatography using 0.9% NaCl solution as a solvent. The Rf value of (99m)TcO4(-) is (≈1). The solvatochromism for the reaction of (99m)Tc with d-glucose was mainly affected by solute permanent dipole-solvent permanent dipole interaction, the dipolar interaction for the reaction of (99m)Tc with of 5,5'-diethyl barbituric acid and for the reaction of (99m)Tc with adenine and thiobarbituric was solute-solvent hydrogen bonding.

Alterations in immune cell subsets and their cytokine secretion profile in childhood idiopathic thrombocytopenic purpura (ITP).

Immune thrombocytopenic purpura (ITP) is acquired autoimmune disease in children characterized by the breakdown of immune tolerance. This work is designed to explore the contribution of different lymphocyte subsets in acute and chronic ITP children. Imbalance in the T helper type 1 (Th1)/Th2 cytokine secretion profile was investigated. The frequency of T (CD3(+), CD4(+), CD8(+)) and B (CD19(+)) lymphocytes, natural killer (NK) (CD16(+) 56(+)) and regulatory T (T(reg)) [CD4(+) CD25(+high) forkhead box protein 3 (FoxP3)(+) ] cells was investigated by flow cytometry in 35 ITP children (15 acute and 20 chronic) and 10 healthy controls. Plasma levels of Th1 cytokines [interferon (IFN-γ) and tumour necrosis factor (TNF-α)] and Th2 [interleukin (IL)-4, IL-6 and IL-10)] cytokines were measured using enzyme-linked immunosorbent assay (ELISA). The percentage of Treg (P < 0·001) and natural killer (NK) (P < 0·001) cells were significantly decreased in ITP patients compared to healthy controls. A negative correlation was reported between the percentage of T(reg) cells and development of acute (r = -0·737; P < 0·01) and chronic (r = -0·515; P < 0·01) disease. All evaluated cytokines (IFN-γ, TNF-α, IL-4, IL-6 and IL-10) were elevated significantly in ITP patients (P < 0·001, P < 0·05, P < 0·05, P < 0·05 and P < 0·001, respectively) compared to controls. In conclusion, our data shed some light on the fundamental role of immune cells and their related cytokines in ITP patients. The loss of tolerance in ITP may contribute to the dysfunction of T(regs). Understanding the role of T cell subsets will permit a better control of autoimmunity through manipulation of their cytokine network.

Extraction of triazine herbicides by polyhydroxyl-polyurethane foam in environmental samples.

In this work, a new type of sorbent (polyhydroxyl-polyurethane foam or PPF) was synthesized by using water hydrolysis of polyurethanediazonium chloride salt. PPF was characterized using different tools (infrared spectra, elemental analysis, scanning electron microscopy and thermogravimetric analysis). It was tested for the extraction of atrazine, prometryn and terbutryn herbicides from environmental samples. The batch technique was conducted to evaluate the effects of initial pH, contact time, temperature, volume of sample and initial concentration of triazine herbicides on the removal of the herbicides from the aqueous solution. The extraction of the herbicides was accomplished in a period ranging from 5-15 min. The experimental data of the sorption was fitted by pseudo-first and pseudo-second-order kinetic mathematical equations and better followed the pseudo-second-order kinetics (R(2) ≈ 0.966). The equilibrium process was accurately described by the Freundlich isotherm model; the average Freundlich constant (1/n) value was 0.68, which was attributed to the heterogeneous surface structure of the PPF. The average capacity of the conventional polyurethane foam material was 0.34 mmol/g for herbicides. The study shows that PPF has the potential to be applied as an efficient sorbent for the extraction of herbicides from real matrix samples.

Synthesis, characterization of low density polyhydroxy polyurethane foam and its application for separation and determination of gold in water and ores samples.

In this work, a new type of sorbent (low density polyhydroxy polyurethane Foam, LPPF) was synthesis by using water hydrolysis of polyurethanediazonium chloride salt. LPPF was characterized using different tools e.g. elemental analysis, UV-vis and IR spectra, TGA, SEM, density and pHZPC. It was tested for separation, preconcentration and determination of gold in environmental samples using batch and dynamic techniques. The sorption experimental data was fitted by the pseudo-first kinetic mathematical equation (R(2)=0.991). The sorption rate of the Au (III) ions is very fast, the half-life (t1/2)≈34 s. The equilibrium process is well described by the Freundlich isotherm model, the R(2) value is 0.967, which attributed to the heterogeneous surface structure of the LPPF. The breakthrough capacity of LPPF and the recovery of gold ions were 0.36 mmol g(-1) (70.5 mg g(-1)) and 99-100%, respectively. The lower detection limit of gold by using spectrophotometric method is 3.3 ng L(-1) with preconcentration factors≈450 (RSD∼1.66%, n=4). The values of ΔG and ΔH for the sorption of gold onto LPPF were -12.5 and -103.5 kJ mol(-1), respectively, which indicate that the sorption of Au (III) onto LPPF is spontaneous and exothermic reaction. The obtained results indicate that the ion chelation and ion association might be the most probable mechanism of gold sorption onto LPPF. The study shows LPPF has the potential of application as an efficient sorbent for the extraction and determination of gold in water, gold alloys pharmaceutical and granite samples.

Determination of total iron in food samples after flow injection preconcentration on polyurethane foam functionalized with N,N-bis(salicylidene)-1,3-propanediamine.

A highly selective flow injection sorption system was developed for the fast determination of total iron in food samples. Iron (III) was reduced to iron (II) by ascorbic acid and preconcentrated on a mini-column packed with polyurethane foam (PUF) functionalized with N,N-bis(salicylidene)-1,3-propanediamine (SPDA). The retained Fe (II) was eluted with hydrochloric acid and subsequently reacted to 2,4,6-tri(2'-pyridyl)-1,3,5-triazine (TPTZ) then measured at 593 nm. The procedure has resulted preconcentration factor 36, sample frequency 20 h(-1) and detection limit 18 µg L(-1). The precision (RSD) was found to be 5.7% and 3.1% at concentration levels 0.1 and 5.0 µg mL(-1) iron (II), respectively. Finally, the method was successfully applied to determination of total iron in reference material and food samples.

Cationic polyelectrolyte copolymer modified polyurethane foam for flow injection preconcentration and separation of trace amounts of ß-lactam antibiotics.

A more sensitive flow injection preconcentration method has been developed for the determination of four ß-lactam antibiotics (BLAs) namely cefaclor, cefotaxime, amoxicillin and ampicillin in urine, pharmaceuticals and milk. A mini-column packed with PUF functionalized with the cationic polyelectrolyte, poly(N-chloranil N,N,N',N'-tetramethylethylene diammonium dichloride) PCTDD, was utilized for selective preconcentration. The detection limits with this method were 3.3, 3.8, 5.1 and 7.0 ng mL(-1) and enrichment factors were 38, 21, 39, and 36 for cefaclor, cefotaxime, amoxicillin and ampicillin, respectively with a sample throughput of 12 h(-1) for all BLAs. Moreover, the BLAs were successfully separated by isocratic elution using a micellar mobile phase. Application of the method developed has resulted in recovery values in the range 95%-109% (RSD≤8.7), 83%-99% (RSD≤9.7) and 91%-103% (RSD≤4.0) for urine, pharmaceuticals and milk samples, respectively.

Chemical studies on polyaniline titanotungstate and its uses to reduction cesium from solutions and polluted milk.

Polyaniline titanotungstate (PATiW) was synthesized by the sol-gel method. Adsorption isotherm studies of Cs(+) from aqueous solution are described. Elemental Composition, chemical solubility, ion-exchange capacity (IEC) and pH-titration curve are studied. Distribution coefficients (K(d)) for 10 metal ions were determined. It was found that the polyaniline titanotungstate is highly selective to Cs(+) and the selectivity order is Cs(+)>>>Zr(4+)>Mo(6+)>V(5+)>As(5+)>Cr(3+)>Co(2+)>Cu(2+)>Zn(2+)>Cd(2+). The adsorbent capacity was determined using the Freundlich and Langmuir adsorption isotherm models. The Cs(+) adsorption isotherm data fit best to the Freundlich isotherm model. The maximum Cs(+) uptake of polyaniline titanotungstate was found to be 217 mg g(-1). Column tests were performed to determine the breakthrough curves with varying bed depths and flow rates in different solutions. The results showed that the half breakthrough time increases proportionally with increasing bed depths. Kinetic studies for removal of cesium from milk were also investigated using a scintillation detector head (NaI).

Novel screen-printed electrode for the determination of dodecyltrimethylammonium bromide in water samples.

The construction and electrochemical response characteristics of a screen-printed electrode (SPE) for the determination of dodecyltrimethylammonium bromide (DTAB) are described. The sensor was based on the use of DTA-tetraphenylborate ion association complex as an electroactive material in screen-printed electrode with dioctylsebacate (DOS) as a solvent mediator. In aqueous solution of pH 3, the sensor displayed a stable response for six months with reproducible potential and linear response for surfactant over the concentration range 1.20 × 10(-2) -5.6 × 10(-7) mol L(-1) at 25 °C with Nernstian slope of 55.95 ± 0.58 mV decade(-1) for detection limit of 6.8 x 10(-6) mol L(-1) . The response time was 6-10 s. The selectivity coefficients indicate excellent selectivity for DTAB over many common cations (e.g. Mg(2+), Na(+), K+, Co(2+), Ni(2+), Ca(2+), Cl(-), I(-), SO(4)(-2) and cetylpyridinium chloride (CPC). The sensor was used successfully for the determining of DTAB in pure form and water samples with average recoveries of 99.98, 98.78, and 99.99%.