KBH4 Concentration Research Articles

Dandelion-like ZIF-67 supported ternary transition metal borides as efficient hydrolysis catalysts for KBH4

The development of high-efficient and low-cost catalysts is crucial for promoting KBH4 hydrolysis to produce hydrogen. Herein, ZIF-67 supported cobalt-molybdenum-nickel based boride (Co–Mo–Ni–B/ZIF-67) nanocomposites with dandelion-like morphology were designed as catalysts of KBH4 hydrolysis reaction and were synthesized via the chemical reduction process. Moreover, the element ratio and the loading amount of Co–Mo–Ni–B were optimized, and effects of KBH4 concentration, KOH concentration, and reaction temperature on catalytic performances were studied. As expected, ZIF-67 substrate avoids the agglomeration of amorphous Co–Mo–Ni–B, and the synergy between ZIF-67 and uniformly dispersed Co–Mo–Ni–B active substances accelerates hydrogen generation rate. As a result, the maximum hydrogen generation rate of 17400 mL min−1 g−1 is achieved with the optimized KOH concentration of 10% and KBH4 concentration of 6% at the reaction temperature of 30 °C. In addition, Co–Mo–Ni–B/ZIF-67 exhibits moderate durability performance with a cyclic retention rate of 51.9 % after five cycles. This dandelion-like structure design provides an idea for the development of efficient catalyst for hydrolysis of borohydrides.

Rapid and effective nitrate reduction over wide pH range using CuxO-CNT with the presence of KBH4: The role of in situ produced hydrogen and zero-valent copper

CNTs-CuxO prepared by impregnation was used with KBH4 to reduce NO3–-N as the first step. CNTs-CuxO was characterized by SEM, EDS-mapping, TEM, XRD and XPS. The NO3–-N reduction batch experiment showed that 100% of NO3–-N removal efficiency was achieved in < 10 min with the initial pH of 3.0, 5.0 and 7.0, NO3–-N concentration of 30 mg(N)/L, CNTs- CuxO dosage of 3 g/L and KBH4 concentration of 3 mmol/L. At the initial pH of 9.0, NO3–-N was completely removed in 15 min. The main product of the first step reaction was NO2–-N, which was accumulated in the solution and rapidly reduced to N2 by NH2SO3H as the second step. The reusability of CNTs-CuxO was evaluated and the experiment result showed that 96% of NO3–-N removal efficiency was achieved in 10 min after CNTs-CuxO was reused for 5 cycles of reaction. Moreover, the Cu2+ dissolution was kept monitored for the reaction system, and the analysis result showed that there was no Cu2+ leaching for all cycles of reutilization.

Nanoscale zero‐valent Ni–Fe alloy catalyst featuring a dual galvanic effect to promote formate formation by CO2 hydrogenation

AbstractGlobal greenhouse effect is being exacerbated by continuously increasing CO2 emissions. Hence, we prepared a nanoscale zero‐valent Ni–Fe alloy featuring a dual galvanic effect to facilitate the formation of formate by CO2 hydrogenation in this work. The properties of the bimetallic nanocatalyst were characterized by various techniques, such as X‐ray photoelectron spectrometer, X‐ray powder diffraction, and high‐resolution transmission electron microscopy, indicating that the major phase composition was an alloy of Ni0 and Fe0. According to the catalyst characterizations before and after the reaction, experimental phenomena, and related literatures, we proposed that the dual galvanic effect between Ni0 and Fe0 was an especially important mechanism to promote the release of BH4‐n(OH)n– (n = 0–3) from KBH4, which acted as the hydrogen donor for CO2. Furthermore, the optimization of process parameters was carried out to determine the optimal experimental conditions: the catalyst dosage was 1 g·L–1, the KBH4 concentration was 0.2 mol·L–1, the reaction temperature was 65 °C, the solution pH was 9.5 and the flue gas velocity was 0.5 L·min–1. The average CO2 conversion efficiency and the formate selectivity reached 60.50 and 54.97%, respectively. Our research results can provide reference for the development of novel CO2 resource utilization technologies. © 2021 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Non-noble nanoalloy of Ni0, Cu0 and Fe0 used for hydride transfer reaction for CO2

Carbon dioxide (CO2) emissions from the combustion of fossil fuels cause the intensification of greenhouse effect. Consequently, a new non-noble nanoalloy of Ni0, Cu0 and Fe0 was prepared for the production of formate (HCO2−) from CO2 in flue gas by hydride transfer reaction under atmospheric pressure and mild temperature in this work. Under the optimal reaction conditions obtained by experimental optimization, which were that catalyst dosage was 1 g·L-1, KBH4 concentration was 0.15 mol·L-1, reaction temperature was 55 °C, solution pH was 9.5 and flow velocity of flue gas was 0.5 L min-1, the CO2 conversion efficiency (CCE) was achieved as 55.97 %. Due to the employment of nanoalloy of Ni0, Cu0 and Fe0, the CCE was improved by about 25 % compared with that in non-catalytic conditions, and meanwhile, the KBH4 dosage was reduced by around 45 %. Based on the catalyst properties before and after the reaction as well as the product detection, we put forward that the electrode potential differences among the ternary transition metals resulted in the improvement of catalyst surface activity to promote KBH4 activation and the hydride transfer reaction for CO2. The work presented herein is conducive to the development of novel transition metal-based nanomaterials for CO2 resource utilization in a low-energy way.

High volume hydrogen evolution from KBH4 hydrolysis with palladium complex catalyst

Abstract In this work, we aimed to present an efficient catalyst in potassium borohydride hydrolysis for hydrogen production. Therefore 5-Amino-2,4-dichlorophenol-3,5-ditertbutylsalisylaldimine-Pd complex was synthesized. FT-IR, SEM, TEM, BET, XRD, Elemental Analysis techniques was employed for characterization of Pd-complex catalyst. When the catalyst tested in KBH4 hydrolysis reaction, some affecting factors were studied such as temperatures (20°C-50 °C), catalyst amounts (5–50 mg), KOH concentrations (0–10%) and KBH4 concentration (2–10%) The results displayed that the synthesized Palladium Schiff Base complex catalyst facilitates potassium borohydride hydrolysis with 25.194 kJ/mol activation energy (Ea). Additionally, Pd Schiff Base complex demonstrated remarkable reusability performance and conserved 95% of its inherent catalytic activity even at sixth recycle.

Potasyum Borhidrit Hidroliz Reaksiyonu İçin Ni-B-P Katalizörünün Kinetik Özellikleri

For the production of hydrogen in the hydrolysis of potassium boron hydride of this product, a high performance Ni-B-P catalyst was synthesized. Catalysts in the unknown state of the chemical industry FTIR, EDS, XRD and SEM analyzes of the catalysts were used to determine the characteristics of the catalysts. Also for potassium boron hydrolysis of Ni2P catalyst; The best Ni / P ratio, optimum KOH concentration, KBH4 concentration, catalyst capacity and kinetic parameters were investigated at different temperatures. The hydrogen production rate of the catalyst was determined to be 665 mL / min * g and the best Ni / P ratio was 0.184. In addition, the reaction rate range n was determined to be 0.2 degrees, so the activation energy value in the arhenius equation was 58,528 kJ / mol.

Selective determination of Cr(Ⅵ) and non-chromatographic speciation analysis of inorganic chromium by chemical vapor generation-inductively coupled plasma mass spectrometry

A novel and sensitive method for the selective determination of Cr(VI) and non-chromatographic speciation of Cr(VI) and Cr(III) was developed based on chemical vapor generation (CVG) in KBH4-acid system for sample introduction into an inductively coupled plasma mass spectrometer (ICP-MS) for detection. The CVG of Cr(VI), rather than Cr(III), was found to be remarkably enhanced in the presence of sodium diethylaminodithioformate (DDTC). After the oxidation of Cr(III) to Cr(VI) by KMnO4, the quantitation of Cr(III) could be obtained based on the difference between the concentration of total chromium and that of Cr(VI). Parameters affecting the CVG reaction and determination of Cr(VI) were evaluated in detail, including the concentrations of DDTC, hydrochloric acid and KBH4, the sample flow rate, as well as the length of reaction and transferring tubing. Under optimal conditions, the CVG efficiency and the limit of detection (LOD) of Cr(VI) were found to be 28% and 0.2 ng mL−1, respectively. The relative standard deviations for seven replicate measurements of 20 ng mL−1 of Cr(Ⅵ) was 1.8%. Furthermore, with excess DDTC (100 μg mL−1) added to the test solutions, possible interferences from Cu2+ (up to 400 ng mL−1) could be eliminated. The proposed method was thus successfully applied to the determination of Cr(VI) in three real water samples and one certified reference water sample, as well as two simulated water samples of Cr(VI) and Cr(III), all with satisfactory results. The possible reasons were discussed for the varied degrees of enhancement between Cr(III) and Cr(VI).

Combining gold nanoparticle-based headspace single-drop microextraction and a paper-based colorimetric assay for selenium determination

A novel method combining headspace single-drop microextraction with a paper-based colorimetric assay was developed. Headspace single-drop microextraction using a microdrop containing unmodified gold nanoparticles (AuNPs) as both the extractant and the colorimetric probe was used for the sensitive and selective determination of Se(IV). The method relies on the color change of the microdrop solution caused by the adsorption of in situ-generated hydrogen selenide on the surface of AuNPs. Following extraction, the microdrop was spotted onto cellulose paper, and scanometric-assisted digital image analysis was used for selenium quantification. The analytical variables affecting the method sensitivity, including the drop volume, the concentrations of KBH4, HCl, and AuNP solutions, and the extraction time, were studied. Under the optimal conditions, a linear correlation between the colorimetric signal and Se(IV) concentration in the range from 15-100 μg L-1 with a limit of quantification of 12 μg L-1 was achieved. The repeatability of the method was studied by the calculation of intraday and interday precision for the standard solutions at concentrations of 20 and 70 μg L-1. The batch-to-batch reproducibility of the AuNPs synthesized under the same conditions was also assessed. The relative standard deviations were less than 7%. The method provided satisfactory results for the determination of selenium in real samples.

Simultaneous absorption and hydrogenation of CO2 from flue gas by KBH4 catalyzed by nickel nanoparticles supported on TiO2

Considering that the carbon dioxide (CO2) emissions resulting from the combustion of fossil fuels significantly aggravate the global greenhouse effect and frequently lead to extreme environmental problems, it was proposed in this work to carry out the simultaneous capture and resource utilization of CO2 from flue gas by using a low-energy method. Importantly, nickel nanoparticles supported on titanium dioxide (Ni NPs@TiO2) was prepared to catalyze potassium borohydride (KBH4) to be transformed into BH4-n(OH)n− (n = 0–3) species with strong hydride donation capacity, which hydrogenated CO2 to formate under atmospheric pressure and mild temperature. The optimum experimental conditions for the catalytic hydrogenation of CO2 were determined by investigating the effects of various factors on the CO2 conversion: the Ni NPs@TiO2 dosage was 1 g·L−1, KBH4 concentration was 0.2 mol·L−1, solution pH was 9.5, reaction temperature was 60 °C and flow velocity of flue gas was 0.5 L·min−1. The average CO2 conversion efficiency was achieved as 51.2% under the optimal conditions. Based on a series of catalyst characterizations, product analyses and related literatures, the catalytic hydrogenation reaction mechanism for the conversion of CO2 to formate was analyzed. This work can provide reference for developing the processes for CO2 emission reduction combined with resource utilization.

Fast and effective hydrogen production from ethanolysis and hydrolysis reactions of potassium borohydride using phosphoric acid

The hydrogen production from potassium borohydride (KBH4) with the ethanolysis and hydrolysis reactions using the phosphoric acid as a catalyst is performed for the first time. KBH4 concentration, phosphoric acid concentration and temperature effects were investigated for the optimum hydrogen production from ethanolysis and hydrolysis reactions of KBH4. The maximum hydrogen production rates in the ethanolysis and hydrolysis reactions with 1 M phosphoric acid are 6423 and 4296 ml min−1g−1, respectively. At the same time, the ethanolysis and hydrolysis reactions with the 1 M acid concentration were completed within 7 and 9 s, respectively. The total conversions obtained for the volume ratio of KBH4/acid of (1:1) were 100%. The power law kinetic model is performed for the kinetic studies. The activation energies for the ethanolysis and hydrolysis reactions of KBH4 using phosphoric acid are found as 2.98 and 2.60 kJ mol−1.

CO2 hydrogenation to formate over nano-scale zero-valent nickel catalyst under atmospheric pressure

To reduce the energy consumption in the current CO2 hydrogenation with gaseous H2, a novel method of CO2 hydrogenation with potassium borohydride (KBH4) at moderate temperature and ambient pressure under the catalysis of nano-scale zero-valent nickel (nZVN) was developed. Under the optimal experimental conditions where the nZVN dosage was 0.2 g, KBH4 concentration was 0.28 mol·L−1, solution pH was 9.5, reaction temperature was 65 °C and residence time was 24 s, the average highest CO2 absorption efficiency of 45.88% with formate selectivity of 40.81% was achieved based on the ion chromatograph (IC) analyses of the reaction products. Especially, the physicochemical properties of the fresh and spent catalysts, such as morphological structure, physical structure properties, phase and crystallization and chemical compositions, were characterized systematically by using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), N2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS). In combination with the relevant references, the heterogenetic catalytic transfer hydrogenation reaction mechanism of CO2 with KBH4 over nZVN was proposed.

Hydrogenation of carbon dioxide under atmospheric pressure and low temperature

In order to realize the effective reduction and utilization of carbon dioxide (CO2) in coal-fired flue gas, a process was developed under atmospheric pressure that uses KBH4 as an efficient hydrogen donor. By investigating the influencing factors of CO2 conversion, the optimal experimental conditions were determined and the average CO2 conversion efficiency of 50.36% was obtained when the KBH4 concentration was 0.2 mol/L, reaction temperature was 50 °C, solution pH was 8, and flow rate was 300 mL/min. The experimental results also verified that the coexisting gases such as sulfur dioxide (SO2), nitric oxide (NO) and oxygen (O2) in flue gas had no significant competition or inhibition effect on CO2 conversion. Meanwhile, the conversion products were analyzed by an Ion Chromatography (IC) and Fourier Transform Infrared Spectroscopy (FT-IR), and the results proved that the main reaction product was formate. Combined with the relevant literatures, the mechanism of CO2 reaction with KBH4 was proposed.

Effect of acid addition on hydrogen production from potassium borohydride hydrolysis

ABSTRACTThis is the first study to produce hydrogen from the potassium borohydride (KBH4) hydrolysis using boric acid (H3BO3). The effect of H3BO3 addition on the hydrogen production via KBH4 hydrolysis was investigated for different H3BO3 and KBH4 molar ratios. In addition, the temperature effect on the hydrolysis reaction was investigated at different temperatures. H3BO3 showed good catalytic activity to produce hydrogen from KBH4 hydrolysis. Activation energy to produce hydrogen from KBH4 hydrolysis was found to be 20.31 kJ/mol. This work also includes kinetic information for the hydrolysis of KBH4. According to the kinetic studies, the reaction between H3BO3 and KBH4 had a reaction order of 0.24 against the H3BO3 concentration, while it had a reaction order of 0.16 against the KBH4 concentration.

Chemical vapor generation coupled with atomic fluorescence spectrometry for the determination of manganese in food samples

A novel method based on chemical vapor generation (CVG) coupled with atomic fluorescence spectrometry (AFS) for the determination of manganese was developed. Room temperature ionic liquids (RTILs) combined with ammonium pyrroldinedithiocarbamate (APDC) were used to synergetically enhance the CVG of Mn. Volatile species of Mn were effectively generated through reduction of acidified analyte solutions in the presence of 0.1% (m/v) APDC and 0.1% (v/v) 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM]PF6) with 2.0% (m/v) KBH4 and 0.1% (m/v) phenanthroline mixed solution. The efficiency for the CVG of manganese was 44%. Some parameters that influenced CVG and subsequent determination were evaluated in detail, such as the concentrations of RTILs, APDC, phenanthroline, nitric acid (HNO3) and KBH4; lengths of reaction tube and transfer tube, as well as interferences. Under optimized experimental conditions, the detection limit (LOD) of Mn(II) was 1.5ngmL−1. Relative standard deviations for five replicate determinations of the standard solution containing 100ngmL−1 Mn(II) was 4.3%. The proposed method was successfully applied to the determination of Mn in water sample and certified environmental reference materials with satisfactory results.

Enhancement effect of room temperature ionic liquids on the chemical vapor generation of lead, cadmium and bismuth for thermospray flame furnace atomic absorption spectrometric determination

A novel method was developed for the chemical vapor generation (CVG) of lead, cadmium and bismuth based on the enhancement effect of room temperature ionic liquids followed by thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) determination. Room temperature ionic liquids (RTILs) and ammonium pyrroldinedithiocarbamate (APDC) were used as enhancement reagents and chelating reagents for the CVG of lead, cadmium and bismuth, respectively. TS-FF-AAS was used for the determination of lead, cadmium and bismuth. The addition of RTILs led to an improvement of 3.5, 3.0 and 4.0 times the CVG efficiencies of Pb, Cd and Bi, respectively. The efficiencies for the CVG of Pb, Cd and Bi in the presence of RTILs and APDC were 55%, 46% and 60%, respectively. Volatile species of Pb, Cd and Bi were effectively generated through reduction of acidified analyte solutions with KBH4 in the presence of 0.02% (m/v) APDC and 0.1% (v/v) 1-butyl-3-methylimidazolium tetrafluoroborate ([C4MIM]BF4). Some parameters that influenced CVG and the subsequent determinations were evaluated in detail, such as the concentrations of RTILs, APDC, HNO3 and KBH4; the flow rates of the carrier gas, lengths of the reaction tube and transfer tube, as well as interferences. Under optimized conditions, the detection limits for Pb, Cd and Bi were 8, 1 and 5 ng mL−1, respectively. Relative standard deviations for five replicate determinations of a standard solution containing 200 ng mL−1 Pb, Cd and Bi were 4.5%, 5.5% and 5.2%, respectively. The proposed method was successfully applied in the determination of Pb, Cd and Bi in certified environmental reference materials with satisfactory results.

Room temperature ionic liquids and ammonium pyrrolidine dithiocarbamate synergetically enhanced the determination of zinc by chemical vapor generation coupled with flame atomic absorption spectrometry

A new method for the determination of zinc based on the synergetic enhancement effect of room temperature ionic liquids (RTILs) and ammonium pyrrolidine dithiocarbamate (APDC) by chemical vapor generation (CVG) coupled with flame atomic absorption spectrometry (FAAS) was developed. RTILs and APDC were used as synergetic enhancement reagents. The addition of RTILs led to a 3.6 times improvement in the CVG efficiency of zinc. Zinc hydride was effectively generated with a 48% vapor generation efficiency (the CVG efficiency was calculated on the basis of the concentrations of zinc before and after CVG) by mixing the acidified analyte solutions with KBH4 in the presence of 0.02% (m/v) APDC and 0.1% (m/v) 1-butyl-3-methylimidazolium tetrafluoroborate ([C4MIM]BF4). Some parameters that influenced CVG and subsequent determination were evaluated in detail, such as the concentrations of RTILs, APDC, HNO3 and KBH4; flow rates of the carrier gas, lengths of the reaction tube and transfer tube, as well as interference from other elements. A detection of limit of 9 ng mL−1 and a relative standard deviation (RSD) of 5.7% at 400 ng mL−1 Zn(II) (n = 5) were obtained under optimal experimental conditions. The proposed method was successfully applied to the determination of zinc in real water samples and certified reference samples with satisfactory results.

Determination of Total Arsenic in Wastewater and Sewage Sludge Samples by Using Hydride-Generation Atomic Fluorescence Spectrometry Under the Optimized Analytical Conditions

In this work, an improved hydride-generation atomic fluorescence spectrometry (HG-AFS) method for the determination of total arsenic (As) in wastewater and sewage sludge samples was applied. The samples were digested completely with mixtures of HNO3 and HClO4. Analytical conditions were studied and optimized through uniform experimental design U*10(108) combined with a single factor test. A mathematical model was established, and a quadratic polynomial stepwise regression analysis by using the DPS software was employed to obtain the factors that impact the fluorescence intensity. This technique is then combined with a single factor test. The optimized experimental conditions were obtained as follows: PMT voltage was 305 V, lamp current was 70 mA, KBH4 concentration was 2.0% (m/v), carrier liquid (HCl) concentration was 5% (v/v), carrier gas (Ar) flow rate was 300 mL min−1, and reaction acidity was 10% (v/v) HCl. The pre-reduction of all forms of As to As(III) was performed by using a mixed solution of 1% thiourea and 1% ascorbic acid. The content of total As was determined under the optimized experimental conditions. The detection limits for total As in wastewater and sewage sludge were 0.09 µg L−1 and 0.01 mg kg−1, respectively. The linear ranges were 0.24–100 µg L−1, and the recovery was 91.0–102.0%. The relative standard deviation (RSD, n = 5) for eleven replicate measurements of the certified reference materials containing 60.6 ± 4.2 µg L−1 As (certified sample of water) and 10.7 ± 0.8 mg kg−1 As (certified sample of soil) were 3.1% and 1.6%, respectively. The proposed method was validated by the analysis of certified reference materials and was successfully applied to the determination of total As in real samples of wastewater and sewage sludge with satisfactory results.

Ultrasensitive determination of cobalt and nickel by atomic fluorescence spectrometry using APDC enhanced chemical vapor generation

Ammonium pyrrolidine dithiocarbamate (APDC) was used to enhance the chemical vapor generation (CVG) efficiency of nickel and cobalt. Volatile nickel and cobalt species were effectively generated through reduction of acidified analyte solution with 2% potassium tetrahydroborate (KBH4) solution in the presence of 0.02% (m/v) APDC. Thus, a new CVG-atomic fluorescence spectrometric (AFS) method was developed for determination of ultratrace nickel and cobalt. Influencing parameters were evaluated in detail, including the complexing reagents, the concentrations of APDC, nitric acid and KBH4, flow rates of carrier gas and shield gas, lengths of the reaction tube and the transfer tube, as well as interferences. Under the optimized conditions, the limits of detection (LOD) were 1ngmL−1 and 6ngmL−1 for nickel and cobalt, respectively. The calibration curves were linear in the range of 10 to 300ngmL−1 and 50 to 1200ngmL−1 for nickel and cobalt, respectively. The potential application of this method was validated by the accurate determination of nickel in three certified reference materials. It was also applied to determination of cobalt in water samples and Vitamin B12 with good recoveries of spiked samples.

Synergetic enhancement effect of room temperature ionic liquids and ammonium pyrrolidine dithiocarbamate on the chemical vapor generation of iron, cobalt and nickel in environmental and biological samples by atomic absorption spectrometric determination

A new method based on chemical vapor generation (CVG) coupled with flame atomic absorption spectrometry (FAAS) was developed for the determination of iron, cobalt and nickel in environmental and biological samples. Room temperature ionic liquids (RTIL) combined with ammonium pyrroldinedithiocarbamate (APDC) were used to synergetically enhance the CVG of iron, cobalt and nickel. The addition of RTIL leads to 2.5, 3.2, 3.0 times improvement in the CVG efficiencies of Fe, Co and Ni, respectively. The efficiencies for the CVG of Fe, Co and Ni in the presence of RTIL and APDC were 42%, 61% and 54%, respectively. Volatile species of iron, cobalt and nickel were effectively generated through reduction of acidified analyte solutions with KBH4 in the presence of 0.02% or 0.01% (m/v) APDC and 0.1% or 0.2% (m/v) 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM]PF6). Some parameters that influenced CVG and subsequent determination were evaluated in detail, such as the concentrations of RTIL, APDC, nitric acid (HNO3) and KBH4; flow rates of carrier gas, lengths of reaction tube and transfer tube, as well as interferences. Under optimized conditions, the detection limits (LODs) for Fe, Co and Ni were 18, 14 and 11 ng mL−1, respectively. Relative standard deviations for five replicate determinations of the standard solution containing 500 ng mL−1Fe, Co and Ni were 5.3%, 4.6% and 4.3%, respectively. The proposed method was successfully applied to the determination of iron, cobalt and nickel in certified environmental and biological reference materials with satisfactory results.

Determination of Sb(III) and Total Sb in Antileishmanial Drugs by Spectrophotometric Flow‐Injection Hydride Generation

A spectrophotometric procedure based on hydride generation and flow analysis is proposed for determination of antimony (III) [Sb(III)] and total antimony (Sb) in pharmaceutical samples. Firstly, Sb(III) reacts with hydrogen species generated in the system, forming antimony hydride. The reaction leads to a decrease in the permanganate concentration and, hence, in the intensity of the color of this specie, which is spectrophotometrically measured at 528 nm. Total Sb is determined as Sb(III) after Sb(V) reduction using 0.02% (m/v) KI. Some parameters, such as the number of channels of the gas phase separator, injection volume, coil length, and KBH4 concentration, are investigated. The system presents a frequency of ca. 100 h−1 and precision <3.0% [expressed as relative standard deviation (RSD) of 30 measurements using a 3.0 mg L−1 Sb(III) solution]. The analytical curve ranging from 0.5 mg L−1 to 5.0 mg L−1 (r>0.998; n=5) permits limit of detection (LOD) and limit of quantification (LOQ) of 83 and 250 µg L−1. For total Sb, the accuracy is checked by atomic absorption spectrometry applying the t test and the results are in accordance at the 95% confidence level. Recovery tests are used to check the accuracy for Sb(III) determination, and the recoveries are between 95% and 105%.