Multiple Pulse Amperometric Detection Research Articles

Multiple pulse amperometry in low pressure chromatography for parallel determination of oxidizable and reducible compounds. Analysis of a green coffee extract as a case study

In this paper, the determination of both oxidizable and reducible compounds within a single chromatographic run is exploited for the first time, using a low-pressure chromatographic system and multiple pulse amperometric detection. The case study selected focussed on the analysis of green coffee extracts. The separation of the compounds was carried out using a 1-cm length monolithic column and an eluent prepared by mixing an aqueous solution of an ion-pair reagent, perfluoroheptanoic acid (PFHpA), and acetonitrile. The parallel determination of oxidizable and reducible compounds was performed by application of two consecutive pulses, E1 = +1.6 V and E2 = −1.5 V. At anodic conditions, the chromatographic peaks for 5-caffeoylquinic acid (5-CQA), caffeine and 5-feruloylquinic acid (5-FQA) were detected, while at cathodic conditions, a chromatographic peak was ascribed for trigonelline. In the developed methodology, the use of multiple pulse amperometry provided better sensitivity if compared to previously described amperometric methodologies determining either oxidizable or reducible compounds. Detection limits for the referred compounds of ca. 1 × 10−5 mol L−1, an analysis rate of 12 h−1 and an acetonitrile consumption of 0.07 mL per analysis were achieved. The approach presented demonstrates the possibility of combining low pressure chromatographic systems and multiple pulse amperometry, in the development of new, low-cost and fast methodologies for multi-analyte determinations.

2D-ReS2 & diamond nanoparticles-based sensor for the simultaneous determination of sunset yellow and tartrazine in a multiple-pulse amperometry FIA system

We present a flow injection system with a multiple pulse amperometric detection (FIA-MPA)-based methodology for the simultaneous analysis of sunset yellow and tartrazine. As transducer, we have developed a novel electrochemical sensor based on the synergistic effect of ReS2 nanosheets and diamond nanoparticles (DNPs). Among several transition dichalcogenides for the sensor development, we have selected ReS2 nanosheets since it yields a better response towards both colourants. Scanning probe microscopy characterization shows that the surface sensor is composed by scattered and stacked ReS2 flakes and large aggregates of DNPs. With this system, the gap between the oxidation potential values of sunset yellow and tartrazine is wide enough to allow the simultaneous determination of both dyes. Under the optimum potential pulse conditions (0.8 and 1.2 V) during 250 ms, a flow rate of 3 mL/min and a volume injection of 250 μL, detection limits of 3.51 × 10−7 M and 2.39 × 10−7 M for sunset yellow and tartrazine, respectively, were obtained. This method exhibits good accuracy and precision with Er minor than 13% and RSD lower than 8% with a sampling frequency of 66 samples per hour. Pineapple jelly samples were analyzed by the standard addition method, obtaining 53.7 mg/kg and 29.0 mg/kg of sunset yellow and tartrazine, respectively. From the analysis of fortified samples, recoveries of 94% and 105% were obtained.

Determination of organophosphorus compounds in water and food samples using a non-enzymatic electrochemical sensor based on silver nanoparticles and carbon nanotubes nanocomposite coupled with batch injection analysis

This work presents, for the first time, a fast and highly sensitive electrochemical method for determination of three organophosphorus compounds (OPs), diazinon (DZN), malathion (MLT), and chlorpyrifos (CLPF), using a modified pyrolytic graphite electrode (PGE) coupled to batch injection analysis system with multiple pulse amperometric detection (BIA–MPA). The PGE was modified by a nanocomposite based on functionalized carbon nanotubes (CNTf) and silver nanoparticles (AgNPs). The OPs samples were directly analyzed on the modified working electrode surface by BIA-MPA system in Britton-Robinson (BR) buffer 0.15 mol L−1 at pH 6.0. The MPA detection of DZN, MLT and CLPF was performed using two potential pulses, which were sequentially applied on modified PGE at −1.3 V (100 ms) and +0.8 V (100 ms) for selective determination of these three OPs and working electrode cleaning, respectively. Under optimized conditions, the sensor presented a linear range of 0.1–20 μmol L−1 for DZN, 1.0–30 μmol L−1 for MLT and from 0.25 to 50 μmol L−1 for CLPF. The limits of detection (LOD) and quantification (LOQ) of 0.35 and 1.18 μmol L−1 for DZN, 0.89 and 2.98 μmol L−1 for MLT, and 0.53 and 1.78 μmol L−1 for CLPF were obtained. The proposed method exhibited high sensitivity of 0.068, 0.030 and 0.043 mA L μmol−1 for DZN, MLT and CLPF detection, respectively. Furthermore, the BIA-MPA system provided an analytical frequency of 71 determinations per hour for direct determination of these OPs in water and food samples. The modified PGE coupled to BIA-MPA system showed a high stability of electrochemical response for OPs detection with relative standard deviation (RSD) of 1.60% (n = 20). The addition-recovery studies of the proposed method were carried out in tap water, orange juice, and apple fruit real samples, which showed suitable recovery values between 77 and 124%. The analytical performance of the developed sensor provides an attractive alternative method for OPs determination with great potential for a fast and sensitive application in contaminated samples with these pesticides.

Novel dual-sensor for creatinine and 8-hydroxy-2'-deoxyguanosine using carbon-paste electrode modified with molecularly imprinted polymers and multiple-pulse amperometry

Abstract We present a novel amperometric dual-imprinted sensor for simultaneous determination of creatinine (Cre) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in human urine and serum. The sensor used multiple-pulse amperometric detection in flow injection analysis (MPA-FIA). Copper oxide nanoparticles were coated with the Cre molecularly-imprinted polymer (CuO@MIP), using methacrylic acid as the functional monomer and N, N′-(1,2-dihydroxyethylene) bis-acrylamide as cross-linker. For 8-OHdG sensing, we embedded platinum nanoparticles in reduced graphene oxide and then coated it with guanosine poly-dopamine MIP (PtNPs-rGO@MIP). A carbon-paste electrode (CPE) was then formed containing both nanocomposites to give the dual MIP sensor (CuO@MIP and PtNPs-rGO@MIP/CPE). We developed a dual-potential waveform as a function of time, with Edet.1 (+0.4 V/150 ms) to determine Cre selectively and Edet.2 (+0.6 V/250 ms) to analyze both compounds simultaneously (Cre and 8-OHdG). Subtracting the two signals at 0.6 V and 0.4 V (using a correction factor), respectively, from each other allowed for quantifying 8-OHdG without interference from Cre. The MIP sensor has a linear range of 0.5–150 μM for creatinine and 0.005–50 μM for 8-OHdG, with limits of detection in nano-molar level. The proposed method is successfully applied for the simultaneous determination of Cre and 8-OHdG in urine and serum samples.

Batch injection analysis with electrochemical detection for the simultaneous determination of the diuretics furosemide and hydrochlorothiazide in synthetic urine and pharmaceutical samples

This works shows the combination of batch-injection analysis with multiple-pulse amperometric detection (BIA-MPA) for the determination of the diuretics furosemide (FRD) and hydrochlorothiazide (HCT) in urine and pharmaceutical samples. Under optimized electrolyte conditions (0.04 mol L−1 Britton-Robinson buffer solution at pH 4.0) FRD was oxidized at + 1.10 V and both compounds were oxidized at + 1.30 V. The MPA detection involves the continuous application of two potential pulses as a function of time to determine FRD at the first potential and HCT at the second after subtracting the FRD current obtained at the second potential. A correction factor was needed because the current of FRD at both potentials was different. A boron-doped diamond working electrode was selected for the simultaneous determination as its surface is less susceptive to fouling. The compounds exhibited a linear response range of 2 to 100 μmol L−1 for HCT (r = 0.9990) and 2 to 300 μmol L−1 for FRD (r = 0.9993), satisfactory repeatability (RSD lower than 5% for n = 30), detection limits of 0.65 μmol L−1 for FRD and 0.63 μmol L−1 for HCT, and analytical frequency of 130 injections per hour. The proposed method was applied for the analysis of synthetic urine samples spiked with both compounds and proper recovery values were obtained (95–110%), confirming the potential application for anti-doping analyses. Moreover, the proposed method was compared to UV–Vis spectrophotometry for the analysis of pharmaceutical formulations and they were found to be statistically similar at the 95% confidence level.

Determination of tumour biomarkers homovanillic and vanillylmandelic acid using flow injection analysis with amperometric detection at a boron doped diamond electrode

A new method for the simultaneous determination of two tumour biomarkers, homovanillic (HVA) and vanillylmandelic acid (VMA), using flow injection analysis (FIA) with amperometric detection (AD) at a commercially available boron doped diamond electrode (BDDE) was developed. It was found that this method is suitable for the determination of HVA (in the presence of VMA) and VMA (in the presence of HVA) in optimum medium of Britton-Robinson buffer (0.04 mol L−1, pH 3.0). Calibration dependences consist of two linear parts for both biomarkers, the first one being in the concentration range from 1 to 10 μmol L−1 and the second one from 10 to 100 μmol L−1 (with obtained LODs 0.44 μmol L−1 for HVA and 0.34 μmol L−1 for VMA, respectively). To minimize any negative effects related to the passivation of the working electrode, suitable cleaning pulses (+2.4 V for 30 s) were imposed on the working electrode after each measurement. An attempt to use FIA with multiple pulse amperometric detection to determine both analytes in one run was not successful. Changing potentials in short intervals in multiple pulse detection probably results in mutual interaction of analytes and/or products of their electrochemical oxidation, thus preventing the application of this approach.

Simultaneous determination of sinapic acid and tyrosol by flow-injection analysis with multiple-pulse amperometric detection

This work describes a simple, fast (frequency of 170 injections h−1), and low-cost method for the simultaneous determination of two antioxidants, sinapic acid and tyrosol, using multiple-pulse amperometric detection at a glassy carbon electrode incorporated in a flow-injection analysis cell. A sequence of potential pulses was selected to detect sinapic acid and tyrosol separately in the course of a single injection step. During the characterization of electrochemical detection, conditions for the determination of the two antioxidants (such as the injected volume and the flow rate) were studied and the analytical figures of merit were calculated. The repeatability (expressed as %) RSD was < 4.0% (n = 10) and excellent linearity was obtained across two concentration ranges from 1.0 to 100 μM; the limits of detection of sinapic acid and tyrosol were around 1.0 μM.

Selective Determination of Verapamil in Pharmaceutics and Urine Using a Boron‐doped Diamond Electrode Coupled to Flow Injection Analysis with Multiple‐pulse Amperometric Detection

AbstractThis work presents a simple and low‐cost method for fast and selective determination of Verapamil (VP) in tablets and human urine samples using a boron‐doped diamond working electrode (BDD) coupled to a flow injection analysis system with multiple pulse amperometric detection (FIA‐MPA). The electrochemical behaviour of VP in 0.1 mol L−1 sulfuric acid showed three merged oxidation peaks at around +1.4 V and upon reverse scan, one reduction peak at 0.0 V (vs. Ag/AgCl). The MPA detection was performed applying a sequence of three potential pulses on BDD electrode: (1) at +1.6 V for VP oxidation, (2) at +0.2 V for reduction of the oxidized product and (3) at +0.1 V for cleaning of the working electrode surface. The FIA system was optimized with injection volume of 150 μL and flow rate of 3.5 mL min−1. The method showed a linear range from 0.8 to 40.0 μmol L−1 (R&gt;0.99) with a low limit of detection of 0.16 μmol L−1, good repeatability (RSD&lt;2.2 %; n=10) and sample throughput (45 h−1). Selective determination of VP in urine was performed at+0.2 V due to absence of interference from ascorbic and uric acids in this potential. The addition‐recovery tests in both samples were close to 100 % and the results were similar to an official method.

Simultaneous determination of dopamine and cysteamine by flow injection with multiple pulse amperometric detection using a boron-doped diamond electrode

A flow injection analysis (FIA) system with multiple pulse amperometric (MPA) detection was proposed for the simultaneous determination of dopamine (DOP) and cysteamine (CYS) using a cathodically pre-treated boron-doped diamond electrode (CPT-BDD). The electrochemical behaviors of DOP and CYS were evaluated by cyclic voltammetry in a potential range from 0 to 1.7 V at a scan rate of 0.05 V s−1 using 0.05 mol L−1 H2SO4 as supporting electrolyte. Two oxidation peaks were observed during anodic potential scanning, at potentials of 0.8 V (DOP) and 1.6 V (CYS). Under optimized experimental conditions, such as potentials E1 = +0.8 V 100 ms−1 (pulse potential at which DOP was oxidized) and E2 = + 1.6 V 200 ms−1 (pulse potential at which both analytes were oxidized), the analytical curves were linear in the concentration ranges from 5.0 × 10−7 to 1.3 × 10−4 mol L−1 for DOP and from 5.0 × 10−7 to 1.5 × 10−4 mol L−1 for CYS, with detection limits of 1.1 × 10−8 and 1.3 × 10−8 mol L−1, respectively.The BDD sensor showed good sensitivity, stability and repeatability (analytical frequency of 165 determinations per hour), and no interference in the electrochemical determination of these analytes in the presence of other compounds. The proposed method was successfully applied using the FIA-MPA method in river water and serum samples, with recoveries close to 100%.

Development of a Novel Versatile Method for Determination of two Antihistamines in Association with Naphazoline Using Cathodically Pretreated Boron‐doped Diamond Electrode

AbstractAntihistamines such as pheniramine (PHN) or chlorpheniramine (CPH) are commonly associated with naphazoline (NPZ) in eye drops and nasal decongestants. In this work, a batch‐injection analysis system with multiple pulse amperometric (BIA‐MPA) detection has been applied for the first time for fast simultaneous determination of naphazoline (NPZ) and pheniramine (PHN) or NPZ and chlorpheniramine (CPH). PHN or CPH was selectively detected at +1.1 V and both PHN and NPZ or CPH and NPZ were detected at +1.3 V using boron doped diamond (BDD) as working electrode and Britton‐Robinson (BR) buffer (pH=10.0) as supporting electrolyte. The current of NPZ can then be obtained by subtraction of the currents detected at both potential pulses and applying a correction factor (CF). The proposed method presented good intra‐day repeatability (RSD between 0.7 and 3.2 % for PHN; 0.7 and 2.1 % for CPH; 1.5 and 4.0 % for NPZ; n=20), high analytical frequency (&gt;80 injections h−1), and limits of detection of 0.64, 0.47 and 0.11 μmol L−1 for PHN, CPH and NPZ, respectively. The results obtained with the proposed method are in agreement with those obtained by HPLC (95 % confidence level).

Determination of Colchicine in Pharmaceutical Formulations and Urine by Multiple-Pulse Amperometric Detection in an FIA System Using Boron-Doped Diamond Electrode

This work presents a simple and fast method for colchicine (CO) determination in pharmaceutical formulations and urine by multiple pulse amperometry (MPA) with flow injection analysis (FIA) system using a boron-doped diamond electrode. In optimized conditions, it was possible to quantify CO in urine samples without interference of uric acid and ascorbic acid. The working linear range for CO quantification was achieved from 1.0 × 10-7 to 0.5 × 10-3mol L-1 with a low limit of detection of 2.14 × 10-8mol L-1. Furthermore, the proposed method showed high repeatability for 10 consecutive injections of 1.0 × 10-4mol L-1 CO (relative standard deviation = 1.28%) and good analytical frequency (30 determinations per hour). The addition and recovery studies in all pharmaceutical samples were approximately 100% and the results for CO determination were compared by high performance liquid chromatography (HPLC) with UV detection.

Fast and Selective Simultaneous Determination of Acetaminophen, Aspirin and Caffeine in Pharmaceutical Products by Batch Injection Analysis with Multiple Pulse Amperometric Detection

AbstractIn this work is presented a method for simultaneous determination of paracetamol (PA), acetylsalicylic acid (ASA) and caffeine (CA) in pharmaceutical tablets, using a bare boron‐doped diamond working electrode (BDDE) coupled to batch injection analysis system with multiple pulse amperometric detection (BIA‐MPA). The optimized sequence of fast potential pulses were applied on BDDE for acquisition of independent amperograms: +1.0 V for PA oxidation, +1.3 V for oxidation of PA and salicylic acid (SA) generated from a previous alkaline hydrolysis of ASA and +1.6 V in which the three analytes are oxidized (PA, SA and CA). Selective determination of PA is performed using the currents obtained at +1.0 V, while SA and CA signals are indirectly obtained using simple subtraction operations between peak currents from each amperogram and correction factors (CF's). The limitations of such approach on the precision and accuracy as function of BIA‐MPA conditions are discussed. Simultaneous determination of the target drugs in pharmaceutical tablets was performed by BIA‐MPA and the results compared to a HPLC‐DAD method. Under optimized conditions, the proposed method exhibits fast responses (180 injections per hour for the simultaneous determination of the three analytes) and suitable precision (RSDPA: 0.78 %; RSDSA: 1.09 %; RSDCA: 2.73 %). BIA‐MPA method is simple, portable and presents relative low‐cost.

Selective and simultaneous determination of indigo carmine and allura red in candy samples at the nano-concentration range by flow injection analysis with multiple pulse amperometric detection

A novel, unique electroanalytical method was developed for the simultaneous quantification of the dyes indigo carmine (IC) and allura red (AR) in candies by coupling flow injection analysis and multiple pulse amperometry with a cathodically pretreated boron-doped diamond electrode, using 0.30 mol L−1 H2SO4 as supporting electrolyte. A dual-potential waveform was employed, causing the electrooxidation of either IC solely or IC and AR simultaneously. Thence, subtraction of current signals was used to quantify IC and AR in the concentration ranges of 70.0–1000 nmol L−1 and 40.0–770 nmol L−1, with limits of detection of 40.0 nmol L−1 and 7.0 nmol L−1, respectively. The proposed method, which permits up to 153 determinations per hour with good precision, was successfully applied in the quantification of these dyes in samples of commercial candies; their obtained contents were similar (at a 95% confidence level) to those from a comparative HPLC method.

Batch Injection Analysis‐Multiple Pulse Amperometric Fingerprint: A Simple Approach for Fast On‐site Screening of Drugs

AbstractIn this work, the association of batch injection analysis with multiple pulse amperometric detection (BIA‐MPA) is presented as a new approach to obtain drugs fingerprints. To illustrate the potential of this screening method, tablets containing sildenafil as the active substance were used. Here, a sequence of three potential pulses as a function of time (+1.3, +1.6 and +2.1 V) were applied on a boron‐doped diamond electrode while reproducible injections were performed in a BIA cell (wall jet configuration). The chemical profile of the respective drug combined three ratios among the peak currents obtained in each amperogram: R1=ipa1.6V/ipa1.3V, R2=ipa2.1V/ipa1.6V, R3=ipa2.1V/ipa1.3V. This simple protocol allowed discrimination between Viagra® (reference)/generic and two smuggled tablets, as well as pure Viagra® from Viagra® adulterated with other electroactive compounds (caffeine, dipyrone, paracetamol and tadalafil). For comparison, screening of these samples was also performed using square wave voltammetry combined with a chemometric method (principal component analysis), in which was achieved similar discrimination by one or other strategy for the most of drugs. This new BIA‐MPA fingerprinting combines desirable features in forensic science such as low cost, simplicity, high sample throughput (two drugs discerned in less than 30 s) and portability (screening at the place of the seizure).

Simultaneous determination of tert-butylhydroquinone, propyl gallate, and butylated hydroxyanisole by flow-injection analysis with multiple-pulse amperometric detection

We report the first amperometric method for the simultaneous determination of tert-butylhydroquinone (tBHQ), propyl gallate (PG), and butylated hydroxyanisole (BHA) using flow injection analysis coupled to multiple-pulse amperometry. A sequence of potential pulses was selected in order to detect tBHQ, PG, and BHA separately in a single injection step at a glassy carbon electrode without the need of a preliminary separation. A mixture of methanol and 0.040M Britton-Robinson buffer was used both as a carrier solution and for dilution of analyzed solutions before injection. The method is precise (RSD < 5%, n = 10), fast (a frequency of 140 injections h−1), provides sufficiently low quantification limits (2.51, 1.45, and 0.85μmolL–1 for tBHQ, PG, and BHA, respectively) and can be easily applied without high demands on instrumentation. As a practical application, the determination of these antioxidants contained in commercial chewing gum samples was carried out by applying a simple extraction procedure.

Simple and Fast Determination of Warfarin in Pharmaceutical Samples Using Boron‐doped Diamond Electrode in BIA and FIA Systems with Multiple Pulse Amperometric Detection

AbstractThis paper proposes the use of the boron‐doped diamond electrode (BDDE) in flow and batch injection analysis (FIA and BIA) systems with multiple‐pulse amperometric (MPA) detection for the determination of warfarin (WA) in pharmaceutical formulations. The electrochemical behavior of WA obtained by cyclic voltammetry (CV) in 0.1 mol L−1 phosphate buffer shows an irreversible oxidation process at +1.0 V (vs Ag/AgCl). The MPA was based on the application of two sequential potential pulses as a function of time on BDDE: (1) for WA detection at +1.2 V/100 ms and; (2) for electrode surface cleaning at −0.2 V/200 ms. Both hydrodynamic systems (FIA‐MPA and BIA‐MPA) used for WA determination achieved high precision (with relative standard deviations around 2 %, n=10), wide linear range (2.0−400.0 μmol L−1), low limits of detection (0.5 μmol L−1) and good analytical frequency (94 h−1 for FIA and 130 h−1 for BIA). The WA determination made by the proposed methods was compared to the official spectrophotometric method. The FIA‐MPA and BIA‐MPA methods are simple and fast, being an attractive option for WA routine analysis in pharmaceutical industries.

Alternative method to obtain the Tafel plot for simple electrode reactions using batch injection analysis coupled with multiple-pulse amperometric detection

The application of the batch injection analysis coupled with multiple-pulse amperometric (BIA-MPA) detection is proposed as an alternative method to obtain the kinetic parameters for simple redox reactions (e.g., Fe(CN)63−/4−, Ru(NH3)3+/2+ and Fe(H2O)63+/2+) from analysis of the Tafel plot (TP). The kinetic studies were performed to permit the ‘in situ’ surface characterisation of thin, boron-doped diamond (BDD) films that exhibit a high conductivity. The evaluation of the apparent equilibrium electrode potential (Eeq) and the kinetic parameters comprising the exchange current (i0), the anodic and cathodic charge-transfer coefficients (αa and αc), as well as the apparent heterogeneous rate constant (ko), were evaluated through the analysis of the Tafel plots. According to the experimental values of ko, the degree of reversibility strongly depends on the particular redox reaction occurring on the surface of BDD. The ko values obtained for the different redox reactions from analysis of the Tafel plot were compared with those obtained using the electrochemical impedance spectroscopy (EIS) technique. A good agreement for the kinetic parameters determined for the different redox reactions using different experimental approaches (TP and EIS) was obtained through the statistical analysis based on the standard deviation obtained for the different ko values, after five different measurements for each redox reaction. The use of the proposed alternative method for the study of simple electrode reactions can be very helpful because these reactions are often used as a ‘probe’ for the ‘in situ’ surface characterisation of new electrode materials developed for different purposes.

A portable electrochemical method for cocaine quantification and rapid screening of common adulterants in seized samples

A simple and robust batch-injection analysis system with square-wave voltammetric (BIA-SWV) detection is proposed for the determination of cocaine and screening of the most common adulterants (benzocaine, caffeine, lidocaine, phenacetin, paracetamol, and procaine) in seized cocaine samples. The sample only requires a dissolution step in electrolyte (0.1molL−1H2SO4) prior injection into the BIA cell. SWV scanning is performed after injection of the sample plug and cocaine and adulterants are electrochemically oxidized on a boron-doped diamond electrode (BDDE), resulting in a unique voltammetric profile. The use of BDDE was essential to achieve, for the first time, the electrochemical oxidation of cocaine in an acid medium. Using the optimized experimental conditions, a linear response was found for cocaine concentrations ranging from 6 to 30mgL−1, with a detection limit of 0.27mgL−1 (0.89μmolL−1). The accuracy of the proposed method was estimated by comparing the results obtained for seized cocaine samples by GC-FID and with the addition and recovery protocol. Furthermore, BIA with multiple pulse amperometric (MPA) detection is also proposed as a promising protocol for faster screening of seized cocaine samples.

A simple and fast batch injection analysis method for simultaneous determination of phenazopyridine, sulfamethoxazole, and trimethoprim on boron-doped diamond electrode

A new analytical procedure for fast and simultaneous determination of sulfamethoxazole (SMX), trimethoprim (TMP) and phenazopyridine (FZP) has been developed. The method is based on batch injection analysis with multiple pulse amperometric detection (BIA-MPA) which offers several desirable features, such as simplicity, reduced costs, robustness, good precision (RSD <3.5%, n=15), high analytical frequency (up to 70injectionsh−1) and generation of small volume of waste by analysis. The BIA-MPA procedure provides linear range from 4 to 320, from 2 to 40 and from 1 to 40mgL−1 and limits of detection of 0.20, 0.15 and 0.05mgL−1 for SMX, TMP and FZP, respectively. The results obtained with the proposed method were compared to those obtained by HPLC and similar results were obtained (95% confidence level).

A high-throughput BIA-MPA method for the simultaneous determination of amiloride and furosemide

In this work, a simple and fast batch injection analysis system with multiple pulse amperometric detection (BIA-MPA) was developed for the simultaneous determination of amiloride (AMD) and furosemide (FMD).