Determination of manganese‐ and manganese‐containing fungicides with lucigenin–Tween‐20‐enhanced chemiluminescence detection

Abstract

A flow-injection (FI) method is reported for the determination of Mn(II), maneb and mancozeb fungicides based on the catalytic effect of Mn(II) on the oxidation of lucigenin and dissolved oxygen in a basic solution. The Tween-20 surfactant has been reported for first time to enhance lucigenin chemiluminescence (CL) intensity in the presence of Mn(II) (53%) and maneb and mancozeb (89%). The calibration graphs were linear in the concentration range of 0.001-1.5 mg L(-1) (R(2) = 0.9982 (n = 11) with a limit of detection (S/N = 3) of 0.1 µg L(-1) for Mn(II) and 0.01-3.0 mg L(-1) [R(2) = 0.9989 and R(2) = 0.9992 (n = 6)] with a limit of detection (S/N =3) of 1.0 µg L(-1) for maneb and mancozeb respectively. Injection throughputs of 90 and 120 h(-1) for Mn(II) and maneb and mancozeb respectively, and relative standard deviations of 1.0-3.4% were obtained in the concentration range studied. The experimental variables, e.g., reagents concentrations, flow rates, sample volume, and photomultiplier tube voltage, were optimized and potential interferences were investigated. The analysis of Mn(II) in river water reference materials (SLRS-4 and SLRS-5) showed good agreement with the certified values incorporating an on-line 8-hydroxyquinoline chelating column in the manifold for removing interfering metal ions. Recoveries for maneb and mancozeb were in the range of 92 ± 5 to 104 ± 3% and 91 ± 2 to 100 ± 4% (n = 3) respectively. The effect of 30 other pesticides (fungicides, herbicides and insecticides) was also examined in the lucigenin-Tween-20 CL system.

Flow‐injection determination of manganese (II) using surfactant enhanced diperiodatonickelate (IV)‐rhodamine 6G chemiluminescence

“…For Mn(II) determination in the drinking water samples, the analytical characteristics of the proposed method were compared with the methods reported previously as shown in Table . The LOD of the proposed method was lower compared with the methods reported in the published literature.…”

“…To evaluate the proposed method' accuracy, certified reference materials for river and seawater samples (National Research Council of Canada) were analyzed for Mn(II) determination. The pH of the river water samples reference material for trace metals (SLRS‐4 and SLRS‐5) and the nearshore seawater reference material for trace metals (CASS‐4) was adjusted to 3.7 with 0.1 M NaOH solution before injecting into the proposed FI CL manifold or analyzed by a reported method . Similarly, the pH of drinking water samples was also adjusted., Brij‐35 was added to all these stock solution samples to make 0.5% solutions.…”

“…Samples were analyzed by the proposed manifold incorporating a 8‐HQ column in a sample carrier stream of a 0.5% (w/v) Brij‐35 solution containing 3.0 × 10 −4 M aqueous HCl. Similarly, the same 10 ml spiked and non‐spiked drinking water sample solutions were also analyzed according to the protocol of the reported FI CL method for validation.…”

“…A series of analytical procedures has been employed for quantitative measurement of Mn in diverse samples, e.g. sequential injection analysis (SIA)‐spectrophotometry, flow‐injection (FI) spectrophotometry, FI chemiluminescence (FI CL) and CL, atomic absorption spectroscopy, inductively coupled plasma atomic emission spectrometry, potentiometry, thermometry, ion‐chromatography CL, and electron spin resonance . Some of these techniques are accurate, simple and sensitive, however, many require large amounts of reagents, lengthy procedures, low sample throughputs, lack of sensitivity and a degree of expertise.…”

A review of recent developments based on chemiluminescence detection systems for pesticides analysis

“…This CL emission was enhanced by the analyte. In parallel, a lucigenin CL system was proposed by the same group [ 55 ] to examine the presence of Mn(II) and Mn(II)‐containing pesticides based on their catalytic effect on oxidation of lucigenin to produce N ‐methylacridone in basic solution, which emitted light. Tween‐20 surfactant was used as the enhancer for this system.…”