Spectrophotometric Determination of 1-Naphthylamine in Aqueous Solution by Coupling with Diazotized 4-Aminobenzophenone

Abstract

The coupling reaction of 1-naphthylamine with diazotized 4-aminobenzophenone in acidic media has been studied by a spectrophotometric method in order to determine trace amounts of 1-naphthylamine. the reaction involves coupling with the diazotized reagent to form an intense pink, water-soluble azo dye which shows maximum absorption at 530 nm. A graph of absorbance versus 1-naphthylamine concentration is linear, indicating that Beer's law is obeyed over the range of 5?00 μg of 1-naphthylamine in a final volume of 25 ml, i.e. 0–4 p.p.m., with a molar absorptivity of 5.15 × 10⁴ 1 m1^?1 cm^?1, a relative error of ?2.3 to +0.63% and a relative standard deviation of 0.84–3.0%, depending on the concentration level. the method represents a sensitive, rapid and simple determination of trace amount of 1-naphthylamine in aqueous solution. Interferences due to foreign organic compounds have been investigated.     

一种测定六价铬的新方法

基于六价铬在稀盐酸介质中氧化盐酸羟胺产生亚硝酸根 ,而亚硝酸根可使对硝基苯胺重氮化并与α -萘胺偶联产生红色偶氮染料 ,提出了分光光度法测定六价铬的新方法。在最佳实验条件下 ,六价铬的浓度在0～ 5 0 μg/2 5mL内服从比耳定律 ,其线性相关系数γ为 0 .9990 ,表观摩尔吸光度ε51 0 为 2 .48× 1 0 4 L·mol- 1 ·cm- 1 。所拟方法用于水样中微量铬的测定 ,结果满意     

Determination of tocopherols,tocopherolquinones and tocopherolhydroquinones by gas chromatography-mass spectrometry and preseparation with lipophilic gel chromatography

A method has been developed for the simultaneous determination of a range of aromatic amines using cation-exchange chromatography performed on a standard ion chromatography column using d.c. amperometric detection. The analytes separated were 2,4- and 2,6-toluenediamine (2,4- and 2,6-TDA), aniline, o-toluidine, benzidine, p-chloroaniline, 4,4'-diaminodiphenyl (4,4'-DDP), m-nitroaniline and 1-naphthylamine. A Dionex CS12 column was used with gradient elution from an initial eluent of 5% CH3CN+35 mM H2SO4 to 27% CH3CN+35 mM H2SO4 (at 35 min). Detection limits in the range 2.6-22.6 microg/l were observed for all analytes except m-nitroaniline, for which the detection limit was 201 microg/l. Linear calibrations and good precision were observed and the method was applied to the determination of benzidine, p-chloroaniline and 1-naphthylamine in wastewater samples. Further, the separation was also used (after some modification of the eluent conditions) for the determination of 2,4- and 2,6-toluene diisocyanate (2,4- and 2,6-TDI) and 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) after their hydrolysis to 2,4-TDA, 2,6-TDA and 4,4'-DDP. Detection limits for 2,6- and 2,4-TDI and 4,4'-MDI were 3.8, 8.2, and 11.2 microg/l, respectively. The method was applied to the determination of diisocyanates in air.     

固相萃取-气相色谱／质谱同时测定卷烟滤嘴中的四种芳香胺

采用固相萃取-气相色谱/质谱(SPE-GC/MS)法同时测定了卷烟抽吸后滤嘴中截留的1-氨基萘、2-氨基萘、3-氨基联苯和4-氨基联苯四种芳香胺.该法采用5%的盐酸超声振荡提取滤嘴中的芳香胺,提取液经液液萃取后进行衍生化和固相萃取,浓缩后进行GC/MS分析.1-氨基萘、2-氨基萘、3-氨基联苯和4-氨基联苯的检出限分别为0.51、0.42、0.18、0.18 ng/mL,相对标准偏差在0.94%～3.02%之间,回收率在92.67%～97.20%之间.该方法用于卷烟滤嘴中四种芳香胺的测定,结果发现不同材料的滤嘴对四种芳香胺有不同的截留作用.     

硅藻土吸附在线柱富集-火焰原子吸收光谱法测定环境水样中痕量铜

提出了硅藻土吸附在线柱富集-火焰原子吸收光谱法测定环境水样中痕量铜的方法。利用硅藻土对环境水样中痕量铜在线预富集,浓集因子达到27.6,使火焰原子吸收光谱法的检测能力达到测定环境水样中痕量铜的要求。方法检出限为0.32μg.L-1,RSD(20μg.L-1)为3.52%,加标回收率为97.0%~105.0%。     

A fluorescence quenching method for the determination of nitrite with Rhodamine 110

A simple and sensitive fluorescence quenching method for the determination of trace nitrite has been developed. The method is based on the reaction of Rhodamine 110 with nitrite in acidic medium to form a new compound, which has much lower fluorescence. The optimum experimental conditions were studied. The linear range was obtained at a nitrite concentration of 1.0 x 10(-8)-3.0 x 10(-7)mol l(-1) with a detection limit of 7.0 x 10(-10) mol l(-1) (S/N=3). The proposed method has been successfully applied to the determination of nitrite in tap water and lake water without extraction.     

毛细管电泳-场强放大样品堆积法检测染发剂中的7种苯胺类物质

建立了毛细管电泳-场强放大样品堆积测定染发剂中4,4′-二氨基二苯甲烷、苯胺、邻甲氧基苯胺、对氨基苯甲醚、3,4-二甲基苯胺、间氨基苯酚、1-萘胺7种苯胺类物质的分析方法。在优化的缓冲溶液体系(0.15 mol/L NaH2PO4,0.015 mol/L 三乙醇胺, pH 2.3)下7种分析物在6.5 min内实现基线分离。考察了样品中添加的磷酸浓度和乙腈浓度、水柱长度、电动进样时间与电压对场强放大富集效率及重现性的影响。最佳的富集条件为: 水柱注入3.45 kPa(0.5 psi)×6 s,样品中添加40%(v/v)乙腈和0.6×10~3mol/L磷酸,进样电压与进样时间为10 kV×10 s。线性范围为3～1000 μg/L(R2＞0.996),检出限为0.26～2.75 μg/L,将已有方法的检测灵敏度提高了1～3个数量级。在2种市售黑色染发剂中均检测到间氨基苯酚,含量分别为7.32 mg/g和1.34 mg/g。平均加标回收率为74%～108%。该方法灵敏度高、快速、重现性好、成本低,可供多种样品基质中痕量苯胺类污染物及其他阳离子物质的测定借鉴使用。     

Trace-level determination of triazines and several degradation products in environmental waters by disk solid-phase extraction and micellar electrokinetic chromatography

An analytical method combining disk solid-phase extraction with micellar electrokinetic chromatography has been developed for the determination of atrazine, simazine, hydroxyatrazine, deisopropylatrazine, deethylatrazine, propazine and prometryn in water samples. The influence of the buffer and sodium dodecyl sulfate (SDS) concentration, pH and organic modifier on the separation has been studied. Baseline separation of the seven triazines was achieved under the following conditions: 10 mM borate buffer, 60 mM SDS, 20% methanol and pH 9.2. C18-bonded silica and poly(styrene-divinylbenzene) (PS-DVB) disks were evaluated for solid-phase extraction of the selected pesticides (11 of water sample). Using two PS-DVB disks, quantitative recoveries were obtained for all pesticides tested. The method was successfully applied for the determination of the seven triazines in drinking and well water at the 0.1 microg l(-1) and 0.5 microg l(-1) concentration levels, respectively. The detection limits for these analytes using the proposed analytical method were within the 0.02-0.06 microg l(-1) range in drinking water and the 0.06-0.30 microg l(-1) range in well water.     

1-萘胺氧化合成1,4-萘醌

研究了在乙酸中,用H2O2氧化1-萘胺合成1,4-萘醌的新方法。 考察了反应温度、反应时间、1-萘胺与H2O2摩尔比、硫酸和H2O2质量分数等因素对产品收率的影响。 得到较优的反应条件为：1-萘胺与H2O2摩尔比为1∶10、H2O2质量分数为5%、硫酸质量分数为45%、反应温度为80 ℃、反应时间为3 h。 在此条件下,1,4-萘醌的收率为52.2%。 该方法具有操作简单、反应时间短和产物易分离等优点。     

Determination of trace formaldehyde by solid substrate-room temperature phosphorescence quenching method based on the rose bengal-potassium bromate-Tween-80 system

A new method for the determination of trace formaldehyde by solid substrate-room temperature phosphorescence quenching method has been proposed. It is based on the facts that rose bengal (R) can emit intense and stable room temperature phosphorescence on the solid substrate of filter paper (SS-RTP). Potassium bromate (KBrO(3)) can oxidize R, which causes the quenching of RTP. In the presence of HCHO, it can react with KBrO(3) to form Br(2) and Br(2) can oxidize R, which causes smart quenching of RTP. The phosphorescence intensity (DeltaI(p)) is directly proportional to the concentration of HCHO. In the presence of Tween-80, the DeltaI(p) will be increased to 9.1 times higher than that without it. The linear range of this method is 0.016-1.6fgspot(-1) (corresponding concentration: 0.040-4.0 pgml(-1), 0.40 microlspot(-1)) with the detection limit of 4.5agspot(-1) (corresponding concentration: 1.1 x 10(-14) gml(-1)). The regression equation for working curve is DeltaI(p)=136.6+28.28m(HCHO)fgspot(-1) (r=0.9935, n=6). This method is sensitive, simple, rapid and has been applied to the determination of trace formaldehyde in real samples with satisfactory results. The mechanism of determination of trace formaldehyde by SS-RTP quenching method based on the rose bengal-KBrO(3)-Tween-80 system is also discussed.     

A novel nitrite sensor based on poly-1-naphthylamine doped by a ferrocenesulfonic-acid-modified electrode

A novel sensor for detecting nitrite based on poly-1-naphthylamine doped by a ferrocenesulfonic acid (PNAFc) modified electrode has been proposed. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) have confirmed that ferrocene-sulfonic acid (Fc) can be doped in poly-1-naphthylamine (PNA) and enhances its electrochemical activity. In a nitrite solution, the PNAFc electrode shows an excellent electrocatalytic activity for the oxidation of nitrite. Based on differential pulse voltammetry (DPV), the response was evaluated with respect to pH, scan rate, temperature, and other variables. The optimum analytical conditions for the determination of nitrite were established. Under optimum conditions, the linear range for nitrite determination was from 0.5 to 100 μM with a detection limit of 0.5 μM. The stability and anti-interference ability of the PNAFc electrode were also evaluated. The results indicate that this sensor is feasible for the determination of nitrite in real water samples. The text was submitted by the authors in English.     

Determination of chromium(III) and total chromium in water by derivative atomic absorption spectrometry using flow injection on-line preconcentration with a double microcolumn.

A rapid and sensitive method has been proposed for the sequential determination of chromium(III) and total chromium in water samples by flame atomic absorption spectrometry combined with a flow injection on-line preconcentration on a double-microcolumn. The chromium(III) and total chromium in samples were retained on a double-microcolumn with a cation exchange resin, respectively, and eluted directly into a nebulizer by 3 mol L(-1) HNO3. The characteristic concentration (gives a derivative absorbance of 0.0044) and the detection limit (3sigma) for chromium were 0.512 microg L(-1) and 0.647 microg L(-1) for a preconcentration time of 1 min, respectively. This is an improvement of 20 and 14-times than those of conventional FI-FAAS. The proposed method allows the determination of chromium in the range of 0-90 microg L(-1) with a relative standard deviation of 3.63% at the 10 microg L(-1) level. The method has been applied for the analysis of chromium in reference water of National Research Center for Certified Reference Materials (GBW08607) and other water samples with satisfactory results.     

Multisyringe Flow Injection Analysis for Determination of 1-Naphthylamine in Water Samples

1-Naphthylamine (NPA) is one of the main degradation products of pesticides derived from naphthalene, and a well-known bladder carcinogen in men. The Griess assay is used for NPA determination because of its high sensitivity and selectivity. The azo dye 4-(sulphophenylazo)-1-naphthylamine is formed, which shows a peak maximum at 540 nm. After optimizing multisyringe flow injection analysis (MSFIA) parameters, the analytical characteristics of the method were obtained, with a working linear range of 0.5 to 14 mg L⁻¹, according to the equation A = 0.0738±0.0019 [NPA] + 0.0028 ± 0.0042, r = 0.9997. Values for RSD (%) and E_rel (%) were calculated for the concentration levels of 0.5, 6 and 12 mg L⁻¹; values obtained were 1.1, 0.4 and 0.3% for RSD and 0.8, 0.3 and 0.2% for E_rel, respectively. LD was 0.01 mg L⁻¹ and LQ was 0.04 mg L⁻¹ NPA. The MSFIA procedure for the determination of NPA was applied to different water samples (well water, tap water, seawater, and wastewater from the EDAR-1, Palma de Mallorca water treatment plant), with satisfactory results and a throughput of 90 samples per hour.     

Preconcentration of chromium(III) and speciation of chromium by electrothermal atomic absorption spectrometry using cellulose adsorbent

A simple and sensitive method has been developed for species selective determination of chromium(III) and chromium(VI) in water by electrothermal atomic absorption spectrometry. The procedure is based on selective absorption of Cr(III) on a cellulose micro column (pH 11, 0.5 mol L(-1) NaCl). Total chromium was subsequently determined after appropriate reduction of Cr(VI) to Cr(III). Recoveries of more than 97% were found. A concentration factor of 100 was achieved. The relative standard deviations (n=10) at the 40 ng L(-1) level for chromium(III) and chromium(VI) were 2.3% and 1.8% and corresponding limits of detection (based on 36) were 1.8 ng L(-1) and 5.1 ng L(-1), respectively. No interference effects have been observed from other investigated species and the method has been successfully applied to natural water samples.     

Flow injection electrogenerated chemiluminescence determination of vanadium and its application to environmental water sample

A selective flow injection electrogenerated chemiluminescence(CL) method for the determination of vanadium is described in this paper. It was based on the chemiluminescence reaction of luminol with vanadium(II), which was on-line electrogenerated from vanadate using a flow-through carbon electrolytic cell. Under the optimal conditions, the CL intensity was linear to the concentration of vanadium in the range of 5.0x10(-10)-1.0x10(-7) gml(-1) with a detection limit of 2x10(-10) gml(-1) vanadium. The relative standard deviation was 4% for 5.0x10(-8) gml(-1) vanadium in 11 repeated measurements. The method has been successfully applied to the determination of vanadium in environmental water samples.     

On-line column preconcentration for the determination of cobalt in sea water by flow-injection chemiluminescence detection

A flow-injection method for the determination of dissolved cobalt(II) in sea water has been studied based on a combination of column preconcentration using 8-quinolinol immobilized on silica gel, fluoride containing metal alkoxide glass (8HQ-MAF) and chemiluminescence detection with a gallic acid-hydrogen peroxide system. Co(II) is selectively recovered from an acidified sample with 8-quinolinol immobilized on silica gel. After elution with dilute hydrochloric acid the resultant eluent is mixed with the reagent solutions, heated to 60 ( degrees )C and then introduced into the CL cell. The analysis time including the 2-min sample load was 8 min per sea water sample with a corresponding detection limit of 0.62 ng l(-1) (3sigma). The average standard deviation calculated for 10 replicate measurements of artificial sea water samples with a concentration of 10 ng l(-1) cobalt was +/-2.1%. The method has been tested with the standard reference sea waters NASS and CASS.     

Sensitive flow injection colorimetry of nitrite by catalytic coupling of N-phenyl-p-phenylenediamine with N,N-dimethylaniline

A rapid, sensitive and selective flow-injection colorimetry method is proposed for the determination of trace amounts of nitrite. It is based on the nitrite's catalytic effect on the oxidative coupling of N-phenyl-p-phenylenediamine with N,N-dimethylaniline to produce a green dye (lambda(max)=735 nm) in the presence of bromate. The change in absorbances of the dye were monitored in continuos flow mode. Linear calibration curves were obtained for the nitrite concentration range 2.0-100 ng ml(-1). The proposed method had a low detection limit (0.6 ng ml(-1)) and high sample throughput (approximately 30 samples h(-1)). The RSD for 10 and 50 ng ml(-1) nitrite were 2.4 and 1.3% (n=10), respectively. The method has been successfully applied to the determination of nitrite in river water samples.     

Selective preconcentration and determination of tributyltin in fresh water by electrothermal atomic absorption spectrometry

A rapid and simple method for separation and determination of tributyltin (TBT) in mineral and tap water is described. The procedure is based on the selective retention of TBT by a chelating resin, Amberlite XAD-2 impregnated with tropolone. The addition of 0.8% sulfuric acid to the water sample leads to the retention of TBT by the resin while monobutyltin (MBT), dibutyltin (DBT) and inorganic tin remain in solution. TBT is eluted with methyl isobutyl ketone (MIBK) obtaining a preconcentration factor of 80. Tin concentration is determined by ETAAS using zirconium coated tubes. Multi-injection and hot injection techniques are used in order to enhance the sensitivity of the method. A detection limit of 14.4 ng L(-1) is achieved with recoveries near to 100%. The procedure has been successfully applied to TBT determination in various fresh water samples.     

Iodine monochloride-amine complexes: an experimental and computational approach to new chiral electrophiles

Lactonizations are important steps in many synthetic sequences. Substrate-controlled reactions that use chiral auxiliaries or chiral alkenes have already been studied in depth. This study focuses on stereoselective reagent-controlled iodolactonizations, by application of a new method that uses complexes of iodine monochloride and various donor molecules. (R)-1,2,3,4-Tetrahydro-1-naphthylamine and other amines with similar structures were found to be efficient in the iodocyclization of 4-aryl-4-pentenoic acids. Calculations were performed on complexes of (R)-1,2,3,4-tetrahydro-1-naphthylamine with XCl (X = I, H) to identify possible reactive species in these iodocyclizations. Calculations were carried out at various levels of theory, including B3 LYP/6-31+G (d,p) by using a modified SDD basis set for iodine.     

Spectrophotometric determination of mercury in environmental sample and fungicides based on its complex with o-carboxy phenyl diazoamino p-azobenzene

In the present method a new reagent o-carboxyphenyl diazoamino p-azobenzene has been synthesised for the determination of mercury spectrophotometrically. The method is based on the reaction of mercury with the reagent in alkaline medium where the reagent is in the aci-form. The purple violet coloured dye-mercury complex showed an absorption maxima at 540 nm. Beer's law is valid over the concentration range of mercury from 0.08 to 0.8 mug ml(-1) (0.08-0.8 ppm). The molar absorptivity and Sandell's sensitivity were found to be 2.22x10(5) mol(-1) cm(-1) and 0.0009 mug cm(-2), respectively. The method has been successfully applied to the determination of mercury in air, water, soil and fungicide samples.