悬浮(乳化)液进样-火焰原子吸收光谱法测定聚合松香中锌

以表面活性剂OP溶液为样品润湿剂,以琼脂溶液为悬浮剂,用悬浮液技术将聚合松香样品制成悬浮液;或以乙醇为溶剂,用乳化剂OP溶液乳化成乳浊液。用乙二醇配制样品空白溶液,建立了悬浮液技术及乳化技术处理样品,快速测定聚合松香中锌的火焰原子吸收光谱(FAAS)法。试验表明,在悬浮液中加入适量盐酸可显著提高锌的吸光度,试液的物理性质与其空白溶液的一致,无背景吸收干扰。对悬浮液的稳定时间、乳化剂的选择、吸光度重复性及检出限进行了考察。测定结果的相对标准偏差小于或等于2.5%,加标回收率为97.1%~103.4%;测定结     

非完全消化-火焰原子发射光谱法测定润滑脂中钙、锂

低温下用硝酸消解样品 ,用乳化剂TritonX 10 0溶解消解产物 ,配制成样品溶液。建立了非完全消化 -火焰原子发射光谱法快速测定润滑脂中钙、锂的分析方法。以La3+ 作为钙的释放剂 ,以硝酸钾作为锂的消电离剂。试液的粘度与对应空白溶液的粘度一致 ,无背景吸收干扰。对样品处理条件、化学干扰、介质的影响及检出限进行了考察。测定结果的相对标准偏差RSD≤ 3 .0 % ,测定结果与灰化法一致。线性范围 :钙 0～ 7.0 μg/mL、锂 0～ 8.0 μg/mL。方法简便、准确     

乳浊液进样—火邹原子吸收光谱法测定润滑脂中锌和铅

将乳浊液进样技术应用于火焰原子吸收光谱法，成功地测定了润滑脂中锌和铅。样品用苯、用基异丁基酮、冰乙酸混合溶剂及硝酸溶解，以吐温－20、邻苯二甲酸二丁酯混合乳化剂乳化成乳浊液，取适量样品乳浊液，加入适量琼脂溶液配制成试液，喷入火焰，以氘灯进行背景吸收扣除，用工作曲线法测定。通过在工作曲线标准系列溶液中加入适量氯化石蜡浊液，以及同样量的氯化石蜡乳浊液，配制成空白溶液作为参比，解决了试液与工作曲线标准溶液粘度不同的问题。提出了配制与试液粘度相同的空白溶液的原理及方法。方法简便、快速、准确。     

非完全消化-火焰原子吸收光谱法测定明胶中钙镁

用非完全消化技术处理明胶样品。低温下用高氯酸-硝酸混合酸(1+3)消解样品,配制成均匀、透明的样品溶液,建立了非完全消化-火焰原子吸收光谱法快速测定明胶中钙、镁的分析方法。以Sr2+作释放剂,用工作曲线法测定。对消解溶剂的选择、化学干扰、混合酸影响、试液与空白溶液粘度一致性、背景吸收干扰及检出限进行了考察,测定结果与灰化法一致,相对误差小于±1.7%,相对标准偏差小于2.2%,方法简便。     

乳化技术-火焰原子吸收光谱法测定油漆中锰和钴

将油漆样品与硝酸 ( 1 +1 )溶液一起煮沸 ,使不溶的无机物以沉淀形式析出 ,用苯 -丙酮 ( 1 +1 )混合溶剂溶解在煮沸过程中所形成的油漆结块 ,过滤 ,以吐温 80为乳化剂将滤液 (由酸溶液及苯 丙酮溶液两部分组成 )乳化成乳浊液。取适量样品乳浊液配制成试液 ,喷入火焰 ,用标准加入法测定。对样品处理方法、乳化剂的选择及干扰进行了考察 ,建立了测定油漆中锰、钴的快速FAAS分析方法。本方法的测定结果与灰化法一致 ,相对误差小于± 0.7%。方法简便、快速、准确。     

乳化技术在火焰原子光谱法中的应用——测定豆油中镁和钾

以OP为乳化剂将豆油的苯溶液乳化成乳浊液。用发射法测定钾 ,以吸收法测定镁。为消除干扰 ,取适量样品乳浊液 ,加入消电离剂NaCl溶液 (测定钾 )或释放剂La 溶液 (测定镁 )配制成试液 ,以蓖麻油乳浊液作为参比溶液 ,用工作曲线法测定。对溶剂及乳化剂的选择、干扰、蓖麻油乳浊液的用量进行了考察。测定结果与灰化法一致 ,相对误差小于 2.9%。方法简便快速。     

乳化技术在火焰原子光谱中的应用——测定豆油中镁和钾

以OP为乳化剂将豆油的苯溶乳液乳化成乳浊液。用发射法测定钾，以吸收法测定镁。为消除干扰，取适量样品乳浊液，加入消电离剂NaCl溶液（测定钾）或释放剂La（Ⅲ）溶液（测定镁）配制成试液，以蓖麻油乳浊液作为参比溶液，用工作曲线法测定。对溶剂及乳化剂的选择、干扰、蓖麻油乳浊液的用量进行了考察。测定结果与灰比法一致，相对误差小于2.9%。方法简便快速。     

乳化进样-火焰原子吸收光谱法测定清漆中钴和锌

将乳化进样应用于火焰原子吸收光谱法 ,成功地测定了清漆中钴和锌。将清漆样品配制成苯溶液 ,再用乳化剂Tri tonX 10 0乳化成乳浊液。在等体积的样品乳浊液及空白溶液中分别加入等量的琼脂溶液可配制成粘度一致的试液及参比溶液。对乳化剂的选择、线性范围及检出限进行了考察。用工作曲线法测定 ,测定结果的相对标准偏差小于 3 .7% ,钴、锌加标回收率分别为 97. 2 %～ 10 4. 7% ,10 1. 9%～ 10 5 . 6 %。方法简便、准确。     

悬浮液进样-火焰原子吸收光谱法测定聚氯乙烯中微量镁

把悬浮液技术应用于火焰原子吸收光谱法,成功地测定了聚氯乙烯中的镁。将过筛聚氯乙烯样品悬浮在琼脂-乙二醇溶液中制成悬浮液,于适量样品悬浮液中,加入释放剂Sr2+配制成试液,喷入空气 乙炔火焰进行镁的测定。对悬浮剂的选择、干扰的消除、检出限及线性范围进行了考察。测定结果的相对标准偏差小于4.2%,加标回收率为96.2%～105.7%。方法简便、准确。     

消解氨溶-火焰原子吸收光谱法测定胶乳中钠

用消解氨溶法处理胶乳样品 ,即先用浓硝酸消解样品 ,再用氨水溶解消解产物 ,建立了在氨性溶液中快速测定胶乳中钠的FAAS法。以硝酸钾溶液作为消电离剂 ,用工作曲线法测定。对样品处理方法、消解产物的溶解性质、线性范围、干扰及检出限进行了考察。测定结果的相对标准偏差 1.7% ,加标回收率 97.3 %～ 10 2.3 %。方法简便、快速、准确。     

The utilization of sodium in sodium zeolite A by broilers

Two identical experiments were conducted with 1-d-old broiler chicks to determine whether the Na in sodium zeolite A (SZA) was utilizable. Three male and three female chicks were randomly assigned to each of eight replicate pens per treatment. A corn-soybean meal basal diet was formulated to contain supplemental levels of 0, .02, .04, .06, .08, and .16% Na from either SZA or NaCl. The diets were isocaloric and isonitrogenous. The Cl level within each dietary Na level was kept constant. Feed and deionized water were offered for ad libitum consumption throughout each 21-d experiments. In both experiments, broiler body weight was increased with each addition of Na from either NaCl or SZA. In Experiment 1, the addition of Na, whether from NaCl or SZA, resulted in an improvement in feed consumption and feed conversion compared with birds fed the control diet. In Experiment 2, body weights of birds fed .04 to .08% Na from SZA were heavier than those fed the same levels from NaCl. Overall the addition of Na from SZA or NaCl resulted in an improvement in body weight, increased feed consumption, and improved feed conversion. Data from these experiments indicated that the Na in SZA was able to be utilized by broilers as efficiently as the Na from NaCl.     

UV-spectrophotometric determination of ampicillin sodium and sulbactam sodium in two-component mixtures

A simple spectrophotometric method is used for the resolution of the binary mixtures of ampicillin sodium and sulbactam sodium. In aqueous solution, zero-order spectra are subject to interference, so first-derivative spectrophotometry was used to enhance the spectral details allowing the determination of ampicillin sodium from the signal at the zero-crossing point for sulbactam sodium at 268 nm. In 0.1 N sodium hydroxide, sulbactam sodium was determined from the absorbance at 260 nm with negligible contribution from ampicillin sodium. Also, sulbactam sodium was determined without interference using first- and second-derivative spectra in 0.1 N sodium hydroxide at 276 nm (peak-height) and 262-284 nm (peak-to-peak), respectively. The method is rapid, simple, does not require a separation step and allows the determination of each drug without interference from the other. The proposed method has been applied successfully to the assay of these drugs in mixtures and in commercial injections.     

Density model for sodium hydroxide–sodium aluminate solutions

The purpose of this paper is to develop a model of the densities of multi-component aqueous electrolyte solutions containing NaOH and NaAl(OH)₄. Coefficients for the Laliberte–Cooper model of multi-component electrolyte solutions were developed from published density data for the NaOH–NaAl(OH)₄–H₂O system. The density data were split into two groups, data for parameterization and data for validation. The model was able to predict the validation data well, with an R² greater than 0.99 for five of seven datasets and greater than 0.95 for all datasets. The model was shown to extrapolate to temperature and composition ranges outside those used for model parameterization. Similarly, using coefficients derived here for NaAl(OH)₄ and published coefficients for NaOH and NaNO₂, the model was shown to accurately predict the density of solutions that contain NaNO₂ in addition to NaOH–NaAl(OH)₄ (R² = 0.993). This indicates that the model coefficients developed here can be incorporated into models of diverse multi-component electrolyte solutions.     

Ototoxicity of sodium nitroprusside

Nitric oxide (NO) not only has normal physiological roles like vasodilation and neurotransmission in the living organism, it could also have possible neurodestructive effects under certain pathological conditions. The present study aimed to determine whether direct exposure of guinea pig cochlea to a NO donor like sodium nitroprusside (SNP), or a nitric oxide synthase (NOS) inhibitor like N(G)-nitro-L-arginine methyl ester (L-NAME), would cause damage to the auditory hair cells. A piece of gelfoam was placed on the round window of the right ear of adult albino guinea pigs. It was then soaked with 0.1 ml of SNP (3.4 microM), 0.1 ml of L-NAME (9.3 microM or 18.5 microM) or 0.1 ml of injection water, the vehicle used to dissolve the above chemicals. Twelve animals receiving SNP were perfused 1 day, 2, 3 and 7 days later, with three animals being used for each survival period. Six animals receiving L-NAME were allowed to survive up to 7 days before perfusion. Eight animals receiving injection water or 0.45% saline were used as controls. With the scanning electron microscope, the inner and outer hair cells were counted over a 1 mm length of the basilar membrane in each turn of every cochlea. The results showed that, in animals treated with L-NAME at both concentrations stated, no significant loss of either inner or outer hair cells was noted in any part of the cochlea studied. However, as early as 1 day after SNP treatment, a striking loss of inner and outer hair cells was observed in the three lower turns of the cochlea. Damage to the outer hair cells was extended to the apical turn with increasing survival period, but no significant loss of inner hair cells was evident in the apical turn at any of the survival periods studied. To rule out the possibility that the effects were due to the presence of cyanide, a metabolite of SNP, hydroxycobalamin was introduced into the scala tympani of three animals through a cannula-osmotic pump device during SNP treatment. There was no significant difference in the results between the groups with and without hydroxycobalamin infusion 7 days after SNP treatment. The present study suggests that an excessive production of NO in the inner ear could lead to extensive loss of hair cells.     

铝酸钠溶液种分过程中草酸钠结晶析出的行为

拜耳法氧化铝生产过程中,草酸钠在铝酸钠溶液晶种分解工序造成诸多负面影响.本文对种分过程草酸钠结晶析出的行为进行研究.用含草酸钠的合成和工业铝酸钠溶液分别进行分解实验,考察草酸钠对分解产物粒度和形貌的影响,并对草酸钠的结晶习性、草酸钠与氢氧化铝之间的相互作用规律进行探究.结果表明,草酸钠在氢氧化铝表面或颗粒间隙结晶析出,使氢氧化铝二次成核增加,并严重阻碍氢氧化铝的附聚,这是其造成产品氢氧化铝粒度细化的主要原因.      

The taste of sodium

Sodium is crucial to physiological function. The responsibility for detecting it is assumed by the taste system, which devotes perhaps one quarter of its resources to the task. Sodium is transduced by passage into a subset of receptor cells, whose activity is relayed to the brain through a discrete gustatory channel. Responses in hindbrain, thalamus, and gustatory cortex identify the quality and concentration of sodium on the tongue. Coding of reinforcement may begin with the pons and ventral forebrain, particularly the lateral and medial hypothalamic nuclei. When body stores are sufficient, behavioral preference for sodium is mild, encompassing low concentrations and marked by weak avidity. This languid response disappears during sodium shortages. Avidity increases, and hypertonic concentrations are most preferred. This behavioral change may result from altered responsiveness in sodium-specific neurons that offer the sodium signal access to mechanisms of reinforcement. Thus, the taste system detects and recognizes sodium, and accords it a reward value commensurate with the needs of the animal.     

磷酸钠-氢氧化钠浸出氟化钙动力学研究

针对现行主流氢氧化钠和碳酸钠浸出低品位白钨矿存在浸出剂用量大,浸出率低的弊端,提出磷酸钠-氢氧化钠-氟化钙协同高效浸出低品位白钨矿的新工艺.氟化钙作为固体氟源,在浸出过程中首先发生溶解并释放出游离的氟离子,再参与白钨矿的浸出反应生成氟磷酸钙沉淀.因此,氟化钙的溶解速率对白钨矿浸出速率有较大影响.文章使用等浸出率法,对磷...